;;; bignum-ashift-right bignum-ashift-left bignum-gcd
;;; bignum-to-float bignum-integer-length
;;; bignum-logical-and bignum-logical-ior bignum-logical-xor
-;;; bignum-logical-not bignum-load-byte bignum-deposit-byte
+;;; bignum-logical-not bignum-load-byte
;;; bignum-truncate bignum-plus-p bignum-compare make-small-bignum
;;; bignum-logbitp bignum-logcount
;;; These symbols define the interface to the compiler:
;;; %bignum-length %bignum-set-length %bignum-ref %bignum-set
;;; %digit-0-or-plusp %add-with-carry %subtract-with-borrow
;;; %multiply-and-add %multiply %lognot %logand %logior %logxor
-;;; %fixnum-to-digit %floor %fixnum-digit-with-correct-sign %ashl
+;;; %fixnum-to-digit %bigfloor %fixnum-digit-with-correct-sign %ashl
;;; %ashr %digit-logical-shift-right))
;;; The following interfaces will either be assembler routines or code
;;; %BIGNUM-SET-LENGTH
;;; %FIXNUM-DIGIT-WITH-CORRECT-SIGN
;;; %SIGN-DIGIT
-;;; %ASHR
+;;; %ASHR
;;; %ASHL
;;; %BIGNUM-0-OR-PLUSP
;;; %DIGIT-LOGICAL-SHIFT-RIGHT
;;; LDB
;;; %FIXNUM-TO-DIGIT
;;; TRUNCATE
-;;; %FLOOR
+;;; %BIGFLOOR
;;;
;;; Note: The floating routines know about the float representation.
;;;
;;; fixnums
;;; logior, logxor, logand
;;; depending on relationals, < (twice) and <= (twice)
-;;; or write compare thing (twice).
+;;; or write compare thing (twice).
;;; LDB on fixnum with bignum result.
;;; DPB on fixnum with bignum result.
;;; TRUNCATE returns zero or one as one value and fixnum or minus fixnum
-;;; for the other value when given (truncate fixnum bignum).
-;;; Returns (truncate bignum fixnum) otherwise.
+;;; for the other value when given (truncate fixnum bignum).
+;;; Returns (truncate bignum fixnum) otherwise.
;;; addition
;;; subtraction (twice)
;;; multiply
;;; Write MASK-FIELD and DEPOSIT-FIELD in terms of logical operations.
;;; DIVIDE
;;; IF (/ x y) with bignums:
-;;; do the truncate, and if rem is 0, return quotient.
-;;; if rem is non-0
-;;; gcd of x and y.
-;;; "truncate" each by gcd, ignoring remainder 0.
-;;; form ratio of each result, bottom is positive.
+;;; do the truncate, and if rem is 0, return quotient.
+;;; if rem is non-0
+;;; gcd of x and y.
+;;; "truncate" each by gcd, ignoring remainder 0.
+;;; form ratio of each result, bottom is positive.
\f
;;;; What's a bignum?
;;; to be able to return the digit somewhere no one looks for real objects.
(defun %bignum-ref (bignum i)
(declare (type bignum-type bignum)
- (type bignum-index i))
+ (type bignum-index i))
(%bignum-ref bignum i))
(defun %bignum-set (bignum i value)
(declare (type bignum-type bignum)
- (type bignum-index i)
- (type bignum-element-type value))
+ (type bignum-index i)
+ (type bignum-element-type value))
(%bignum-set bignum i value))
;;; Return T if digit is positive, or NIL if negative.
#!-sb-fluid (declaim (inline %bignum-0-or-plusp))
(defun %bignum-0-or-plusp (bignum len)
(declare (type bignum-type bignum)
- (type bignum-index len))
+ (type bignum-index len))
(%digit-0-or-plusp (%bignum-ref bignum (1- len))))
;;; This should be in assembler, and should not cons intermediate
;;; together a, b, and an incoming carry.
(defun %add-with-carry (a b carry)
(declare (type bignum-element-type a b)
- (type (mod 2) carry))
+ (type (mod 2) carry))
(%add-with-carry a b carry))
;;; This should be in assembler, and should not cons intermediate
;;; We really do: a - b - 1 + borrow, where borrow is either 0 or 1.
(defun %subtract-with-borrow (a b borrow)
(declare (type bignum-element-type a b)
- (type (mod 2) borrow))
+ (type (mod 2) borrow))
(%subtract-with-borrow a b borrow))
;;; Multiply two digit-size numbers, returning a 2*digit-size result
;;; accumulating partial results which is where the res-digit comes
;;; from.
(defun %multiply-and-add (x-digit y-digit carry-in-digit
- &optional (res-digit 0))
+ &optional (res-digit 0))
(declare (type bignum-element-type x-digit y-digit res-digit carry-in-digit))
(%multiply-and-add x-digit y-digit carry-in-digit res-digit))
(%lognot digit))
;;; Each of these does the digit-size unsigned op.
-#!-sb-fluid (declaim (inline %logand %logior %logxor))
+(declaim (inline %logand %logior %logxor))
(defun %logand (a b)
(declare (type bignum-element-type a b))
(logand a b))
;;; dividing the first two as a 2*digit-size integer by the third.
;;;
;;; Do weird LET and SETQ stuff to bamboozle the compiler into allowing
-;;; the %FLOOR transform to expand into pseudo-assembler for which the
+;;; the %BIGFLOOR transform to expand into pseudo-assembler for which the
;;; compiler can later correctly allocate registers.
-(defun %floor (a b c)
+(defun %bigfloor (a b c)
(let ((a a) (b b) (c c))
(declare (type bignum-element-type a b c))
(setq a a b b c c)
- (%floor a b c)))
+ (%bigfloor a b c)))
;;; Convert the digit to a regular integer assuming that the digit is signed.
(defun %fixnum-digit-with-correct-sign (digit)
;;; unsigned.
(defun %ashr (data count)
(declare (type bignum-element-type data)
- (type (mod #.sb!vm:n-word-bits) count))
+ (type (mod #.sb!vm:n-word-bits) count))
(%ashr data count))
;;; This takes a digit-size quantity and shifts it to the left,
;;; returning a digit-size quantity.
(defun %ashl (data count)
(declare (type bignum-element-type data)
- (type (mod #.sb!vm:n-word-bits) count))
+ (type (mod #.sb!vm:n-word-bits) count))
(%ashl data count))
;;; Do an unsigned (logical) right shift of a digit by Count.
(defun %digit-logical-shift-right (data count)
(declare (type bignum-element-type data)
- (type (mod #.sb!vm:n-word-bits) count))
+ (type (mod #.sb!vm:n-word-bits) count))
(%digit-logical-shift-right data count))
;;; Change the length of bignum to be newlen. Newlen must be the same or
;;; smaller than the old length, and any elements beyond newlen must be zeroed.
(defun %bignum-set-length (bignum newlen)
(declare (type bignum-type bignum)
- (type bignum-index newlen))
+ (type bignum-index newlen))
(%bignum-set-length bignum newlen))
;;; This returns 0 or "-1" depending on whether the bignum is positive. This
#!-sb-fluid (declaim (inline %sign-digit))
(defun %sign-digit (bignum len)
(declare (type bignum-type bignum)
- (type bignum-index len))
+ (type bignum-index len))
(%ashr (%bignum-ref bignum (1- len)) (1- digit-size)))
;;; These take two digit-size quantities and compare or contrast them
;;; without wasting time with incorrect type checking.
-#!-sb-fluid (declaim (inline %digit-compare %digit-greater))
+(declaim (inline %digit-compare %digit-greater))
(defun %digit-compare (x y)
(= x y))
(defun %digit-greater (x y)
(defun add-bignums (a b)
(declare (type bignum-type a b))
(let ((len-a (%bignum-length a))
- (len-b (%bignum-length b)))
+ (len-b (%bignum-length b)))
(declare (type bignum-index len-a len-b))
(multiple-value-bind (a len-a b len-b)
- (if (> len-a len-b)
- (values a len-a b len-b)
- (values b len-b a len-a))
+ (if (> len-a len-b)
+ (values a len-a b len-b)
+ (values b len-b a len-a))
(declare (type bignum-type a b)
- (type bignum-index len-a len-b))
+ (type bignum-index len-a len-b))
(let* ((len-res (1+ len-a))
- (res (%allocate-bignum len-res))
- (carry 0))
- (declare (type bignum-index len-res)
- (type bignum-type res)
- (type (mod 2) carry))
- (dotimes (i len-b)
- (declare (type bignum-index i))
- (multiple-value-bind (v k)
- (%add-with-carry (%bignum-ref a i) (%bignum-ref b i) carry)
- (declare (type bignum-element-type v)
- (type (mod 2) k))
- (setf (%bignum-ref res i) v)
- (setf carry k)))
- (if (/= len-a len-b)
- (finish-add a res carry (%sign-digit b len-b) len-b len-a)
- (setf (%bignum-ref res len-a)
- (%add-with-carry (%sign-digit a len-a)
- (%sign-digit b len-b)
- carry)))
- (%normalize-bignum res len-res)))))
+ (res (%allocate-bignum len-res))
+ (carry 0))
+ (declare (type bignum-index len-res)
+ (type bignum-type res)
+ (type (mod 2) carry))
+ (dotimes (i len-b)
+ (declare (type bignum-index i))
+ (multiple-value-bind (v k)
+ (%add-with-carry (%bignum-ref a i) (%bignum-ref b i) carry)
+ (declare (type bignum-element-type v)
+ (type (mod 2) k))
+ (setf (%bignum-ref res i) v)
+ (setf carry k)))
+ (if (/= len-a len-b)
+ (finish-add a res carry (%sign-digit b len-b) len-b len-a)
+ (setf (%bignum-ref res len-a)
+ (%add-with-carry (%sign-digit a len-a)
+ (%sign-digit b len-b)
+ carry)))
+ (%normalize-bignum res len-res)))))
;;; This takes the longer of two bignums and propagates the carry through its
;;; remaining high order digits.
(defun finish-add (a res carry sign-digit-b start end)
(declare (type bignum-type a res)
- (type (mod 2) carry)
- (type bignum-element-type sign-digit-b)
- (type bignum-index start end))
+ (type (mod 2) carry)
+ (type bignum-element-type sign-digit-b)
+ (type bignum-index start end))
(do ((i start (1+ i)))
((= i end)
(setf (%bignum-ref res end)
- (%add-with-carry (%sign-digit a end) sign-digit-b carry)))
+ (%add-with-carry (%sign-digit a end) sign-digit-b carry)))
(declare (type bignum-index i))
(multiple-value-bind (v k)
- (%add-with-carry (%bignum-ref a i) sign-digit-b carry)
+ (%add-with-carry (%bignum-ref a i) sign-digit-b carry)
(setf (%bignum-ref res i) v)
(setf carry k)))
(values))
;;; function to call that fixes up the result returning any useful values, such
;;; as the result. This macro may evaluate its arguments more than once.
(sb!xc:defmacro subtract-bignum-loop (a len-a b len-b res len-res return-fun)
- (let ((borrow (gensym))
- (a-digit (gensym))
- (a-sign (gensym))
- (b-digit (gensym))
- (b-sign (gensym))
- (i (gensym))
- (v (gensym))
- (k (gensym)))
+ (with-unique-names (borrow a-digit a-sign b-digit b-sign i v k)
`(let* ((,borrow 1)
- (,a-sign (%sign-digit ,a ,len-a))
- (,b-sign (%sign-digit ,b ,len-b)))
+ (,a-sign (%sign-digit ,a ,len-a))
+ (,b-sign (%sign-digit ,b ,len-b)))
(declare (type bignum-element-type ,a-sign ,b-sign))
(dotimes (,i ,len-res)
- (declare (type bignum-index ,i))
- (let ((,a-digit (if (< ,i ,len-a) (%bignum-ref ,a ,i) ,a-sign))
- (,b-digit (if (< ,i ,len-b) (%bignum-ref ,b ,i) ,b-sign)))
- (declare (type bignum-element-type ,a-digit ,b-digit))
- (multiple-value-bind (,v ,k)
- (%subtract-with-borrow ,a-digit ,b-digit ,borrow)
- (setf (%bignum-ref ,res ,i) ,v)
- (setf ,borrow ,k))))
+ (declare (type bignum-index ,i))
+ (let ((,a-digit (if (< ,i ,len-a) (%bignum-ref ,a ,i) ,a-sign))
+ (,b-digit (if (< ,i ,len-b) (%bignum-ref ,b ,i) ,b-sign)))
+ (declare (type bignum-element-type ,a-digit ,b-digit))
+ (multiple-value-bind (,v ,k)
+ (%subtract-with-borrow ,a-digit ,b-digit ,borrow)
+ (setf (%bignum-ref ,res ,i) ,v)
+ (setf ,borrow ,k))))
(,return-fun ,res ,len-res))))
) ;EVAL-WHEN
(defun subtract-bignum (a b)
(declare (type bignum-type a b))
(let* ((len-a (%bignum-length a))
- (len-b (%bignum-length b))
- (len-res (1+ (max len-a len-b)))
- (res (%allocate-bignum len-res)))
+ (len-b (%bignum-length b))
+ (len-res (1+ (max len-a len-b)))
+ (res (%allocate-bignum len-res)))
(declare (type bignum-index len-a len-b len-res)) ;Test len-res for bounds?
(subtract-bignum-loop a len-a b len-b res len-res %normalize-bignum)))
;;; results, such as GCD, use this. It assumes Result is big enough for the
;;; result.
(defun subtract-bignum-buffers-with-len (a len-a b len-b result len-res)
- (declare (type bignum-type a b)
- (type bignum-index len-a len-b))
+ (declare (type bignum-type a b result)
+ (type bignum-index len-a len-b len-res))
(subtract-bignum-loop a len-a b len-b result len-res
- %normalize-bignum-buffer))
+ %normalize-bignum-buffer))
(defun subtract-bignum-buffers (a len-a b len-b result)
- (declare (type bignum-type a b)
- (type bignum-index len-a len-b))
+ (declare (type bignum-type a b result)
+ (type bignum-index len-a len-b))
(subtract-bignum-loop a len-a b len-b result (max len-a len-b)
- %normalize-bignum-buffer))
+ %normalize-bignum-buffer))
\f
;;;; multiplication
(defun multiply-bignums (a b)
(declare (type bignum-type a b))
(let* ((a-plusp (%bignum-0-or-plusp a (%bignum-length a)))
- (b-plusp (%bignum-0-or-plusp b (%bignum-length b)))
- (a (if a-plusp a (negate-bignum a)))
- (b (if b-plusp b (negate-bignum b)))
- (len-a (%bignum-length a))
- (len-b (%bignum-length b))
- (len-res (+ len-a len-b))
- (res (%allocate-bignum len-res))
- (negate-res (not (eq a-plusp b-plusp))))
+ (b-plusp (%bignum-0-or-plusp b (%bignum-length b)))
+ (a (if a-plusp a (negate-bignum a)))
+ (b (if b-plusp b (negate-bignum b)))
+ (len-a (%bignum-length a))
+ (len-b (%bignum-length b))
+ (len-res (+ len-a len-b))
+ (res (%allocate-bignum len-res))
+ (negate-res (not (eq a-plusp b-plusp))))
(declare (type bignum-index len-a len-b len-res))
(dotimes (i len-a)
(declare (type bignum-index i))
(let ((carry-digit 0)
- (x (%bignum-ref a i))
- (k i))
- (declare (type bignum-index k)
- (type bignum-element-type carry-digit x))
- (dotimes (j len-b)
- (multiple-value-bind (big-carry res-digit)
- (%multiply-and-add x
- (%bignum-ref b j)
- (%bignum-ref res k)
- carry-digit)
- (declare (type bignum-element-type big-carry res-digit))
- (setf (%bignum-ref res k) res-digit)
- (setf carry-digit big-carry)
- (incf k)))
- (setf (%bignum-ref res k) carry-digit)))
+ (x (%bignum-ref a i))
+ (k i))
+ (declare (type bignum-index k)
+ (type bignum-element-type carry-digit x))
+ (dotimes (j len-b)
+ (multiple-value-bind (big-carry res-digit)
+ (%multiply-and-add x
+ (%bignum-ref b j)
+ (%bignum-ref res k)
+ carry-digit)
+ (declare (type bignum-element-type big-carry res-digit))
+ (setf (%bignum-ref res k) res-digit)
+ (setf carry-digit big-carry)
+ (incf k)))
+ (setf (%bignum-ref res k) carry-digit)))
(when negate-res (negate-bignum-in-place res))
(%normalize-bignum res len-res)))
(defun multiply-bignum-and-fixnum (bignum fixnum)
(declare (type bignum-type bignum) (type fixnum fixnum))
(let* ((bignum-plus-p (%bignum-0-or-plusp bignum (%bignum-length bignum)))
- (fixnum-plus-p (not (minusp fixnum)))
- (bignum (if bignum-plus-p bignum (negate-bignum bignum)))
- (bignum-len (%bignum-length bignum))
- (fixnum (if fixnum-plus-p fixnum (- fixnum)))
- (result (%allocate-bignum (1+ bignum-len)))
- (carry-digit 0))
+ (fixnum-plus-p (not (minusp fixnum)))
+ (bignum (if bignum-plus-p bignum (negate-bignum bignum)))
+ (bignum-len (%bignum-length bignum))
+ (fixnum (if fixnum-plus-p fixnum (- fixnum)))
+ (result (%allocate-bignum (1+ bignum-len)))
+ (carry-digit 0))
(declare (type bignum-type bignum result)
- (type bignum-index bignum-len)
- (type bignum-element-type fixnum carry-digit))
+ (type bignum-index bignum-len)
+ (type bignum-element-type fixnum carry-digit))
(dotimes (index bignum-len)
(declare (type bignum-index index))
(multiple-value-bind (next-digit low)
- (%multiply-and-add (%bignum-ref bignum index) fixnum carry-digit)
- (declare (type bignum-element-type next-digit low))
- (setf carry-digit next-digit)
- (setf (%bignum-ref result index) low)))
+ (%multiply-and-add (%bignum-ref bignum index) fixnum carry-digit)
+ (declare (type bignum-element-type next-digit low))
+ (setf carry-digit next-digit)
+ (setf (%bignum-ref result index) low)))
(setf (%bignum-ref result bignum-len) carry-digit)
(unless (eq bignum-plus-p fixnum-plus-p)
(negate-bignum-in-place result))
(defun multiply-fixnums (a b)
(declare (fixnum a b))
(let* ((a-minusp (minusp a))
- (b-minusp (minusp b)))
+ (b-minusp (minusp b)))
(multiple-value-bind (high low)
- (%multiply (if a-minusp (- a) a)
- (if b-minusp (- b) b))
+ (%multiply (if a-minusp (- a) a)
+ (if b-minusp (- b) b))
(declare (type bignum-element-type high low))
(if (and (zerop high)
- (%digit-0-or-plusp low))
- (let ((low (sb!ext:truly-the (unsigned-byte #.(1- sb!vm:n-word-bits))
- (%fixnum-digit-with-correct-sign low))))
- (if (eq a-minusp b-minusp)
- low
- (- low)))
- (let ((res (%allocate-bignum 2)))
- (%bignum-set res 0 low)
- (%bignum-set res 1 high)
- (unless (eq a-minusp b-minusp) (negate-bignum-in-place res))
- (%normalize-bignum res 2))))))
+ (%digit-0-or-plusp low))
+ (let ((low (sb!ext:truly-the (unsigned-byte #.(1- sb!vm:n-word-bits))
+ (%fixnum-digit-with-correct-sign low))))
+ (if (eq a-minusp b-minusp)
+ low
+ (- low)))
+ (let ((res (%allocate-bignum 2)))
+ (%bignum-set res 0 low)
+ (%bignum-set res 1 high)
+ (unless (eq a-minusp b-minusp) (negate-bignum-in-place res))
+ (%normalize-bignum res 2))))))
\f
;;;; BIGNUM-REPLACE and WITH-BIGNUM-BUFFERS
(eval-when (:compile-toplevel :execute)
(sb!xc:defmacro bignum-replace (dest
- src
- &key
- (start1 '0)
- end1
- (start2 '0)
- end2
- from-end)
+ src
+ &key
+ (start1 '0)
+ end1
+ (start2 '0)
+ end2
+ from-end)
(sb!int:once-only ((n-dest dest)
- (n-src src))
- (let ((n-start1 (gensym))
- (n-end1 (gensym))
- (n-start2 (gensym))
- (n-end2 (gensym))
- (i1 (gensym))
- (i2 (gensym))
- (end1 (or end1 `(%bignum-length ,n-dest)))
- (end2 (or end2 `(%bignum-length ,n-src))))
- (if from-end
- `(let ((,n-start1 ,start1)
- (,n-start2 ,start2))
- (do ((,i1 (1- ,end1) (1- ,i1))
- (,i2 (1- ,end2) (1- ,i2)))
- ((or (< ,i1 ,n-start1) (< ,i2 ,n-start2)))
- (declare (fixnum ,i1 ,i2))
- (%bignum-set ,n-dest ,i1
- (%bignum-ref ,n-src ,i2))))
- `(let ((,n-end1 ,end1)
- (,n-end2 ,end2))
- (do ((,i1 ,start1 (1+ ,i1))
- (,i2 ,start2 (1+ ,i2)))
- ((or (>= ,i1 ,n-end1) (>= ,i2 ,n-end2)))
- (declare (type bignum-index ,i1 ,i2))
- (%bignum-set ,n-dest ,i1
- (%bignum-ref ,n-src ,i2))))))))
+ (n-src src))
+ (with-unique-names (n-start1 n-end1 n-start2 n-end2 i1 i2)
+ (let ((end1 (or end1 `(%bignum-length ,n-dest)))
+ (end2 (or end2 `(%bignum-length ,n-src))))
+ (if from-end
+ `(let ((,n-start1 ,start1)
+ (,n-start2 ,start2))
+ (do ((,i1 (1- ,end1) (1- ,i1))
+ (,i2 (1- ,end2) (1- ,i2)))
+ ((or (< ,i1 ,n-start1) (< ,i2 ,n-start2)))
+ (declare (fixnum ,i1 ,i2))
+ (%bignum-set ,n-dest ,i1 (%bignum-ref ,n-src ,i2))))
+ (if (eql start1 start2)
+ `(let ((,n-end1 (min ,end1 ,end2)))
+ (do ((,i1 ,start1 (1+ ,i1)))
+ ((>= ,i1 ,n-end1))
+ (declare (type bignum-index ,i1))
+ (%bignum-set ,n-dest ,i1 (%bignum-ref ,n-src ,i1))))
+ `(let ((,n-end1 ,end1)
+ (,n-end2 ,end2))
+ (do ((,i1 ,start1 (1+ ,i1))
+ (,i2 ,start2 (1+ ,i2)))
+ ((or (>= ,i1 ,n-end1) (>= ,i2 ,n-end2)))
+ (declare (type bignum-index ,i1 ,i2))
+ (%bignum-set ,n-dest ,i1 (%bignum-ref ,n-src ,i2))))))))))
(sb!xc:defmacro with-bignum-buffers (specs &body body)
#!+sb-doc
"WITH-BIGNUM-BUFFERS ({(var size [init])}*) Form*"
(sb!int:collect ((binds)
- (inits))
+ (inits))
(dolist (spec specs)
(let ((name (first spec))
- (size (second spec)))
- (binds `(,name (%allocate-bignum ,size)))
- (let ((init (third spec)))
- (when init
- (inits `(bignum-replace ,name ,init))))))
+ (size (second spec)))
+ (binds `(,name (%allocate-bignum ,size)))
+ (let ((init (third spec)))
+ (when init
+ (inits `(bignum-replace ,name ,init))))))
`(let* ,(binds)
,@(inits)
,@body)))
;; check in normal use, and are disabled here.
(sb!xc:defmacro gcd-assert (&rest args)
(if nil
- `(assert ,@args)))
+ `(assert ,@args)))
;; We'll be doing a lot of modular arithmetic.
- (sb!xc:defmacro M (form)
+ (sb!xc:defmacro modularly (form)
`(logand all-ones-digit ,form)))
;;; I'm not sure why I need this FTYPE declaration. Compiled by the
;;; it, we pay a heavy price in BIGNUM-GCD when compiled by the
;;; cross-compiler. -- CSR, 2004-07-19
(declaim (ftype (sfunction (bignum-type bignum-index bignum-type bignum-index)
- sb!vm::positive-fixnum)
- bignum-factors-of-two))
+ (and unsigned-byte fixnum))
+ bignum-factors-of-two))
(defun bignum-factors-of-two (a len-a b len-b)
(declare (type bignum-index len-a len-b) (type bignum-type a b))
(do ((i 0 (1+ i))
(declare (type bignum-index i end))
(let ((or-digits (%logior (%bignum-ref a i) (%bignum-ref b i))))
(unless (zerop or-digits)
- (return (do ((j 0 (1+ j))
- (or-digits or-digits (%ashr or-digits 1)))
- ((oddp or-digits) (+ (* i digit-size) j))
- (declare (type (mod #.sb!vm:n-word-bits) j))))))))
+ (return (do ((j 0 (1+ j))
+ (or-digits or-digits (%ashr or-digits 1)))
+ ((oddp or-digits) (+ (* i digit-size) j))
+ (declare (type (mod #.sb!vm:n-word-bits) j))))))))
;;; Multiply a bignum buffer with a fixnum or a digit, storing the
;;; result in another bignum buffer, and without using any
;;; MULTIPLY-BIGNUM-AND-FIXNUM.
(declaim (inline multiply-bignum-buffer-and-smallnum-to-buffer))
(defun multiply-bignum-buffer-and-smallnum-to-buffer (bignum bignum-len
- smallnum res)
+ smallnum res)
(declare (type bignum-type bignum))
(let* ((bignum-plus-p (%bignum-0-or-plusp bignum bignum-len))
- (smallnum-plus-p (not (minusp smallnum)))
- (smallnum (if smallnum-plus-p smallnum (- smallnum)))
- (carry-digit 0))
+ (smallnum-plus-p (not (minusp smallnum)))
+ (smallnum (if smallnum-plus-p smallnum (- smallnum)))
+ (carry-digit 0))
(declare (type bignum-type bignum res)
- (type bignum-index bignum-len)
- (type bignum-element-type smallnum carry-digit))
+ (type bignum-index bignum-len)
+ (type bignum-element-type smallnum carry-digit))
(unless bignum-plus-p
(negate-bignum-buffer-in-place bignum bignum-len))
(dotimes (index bignum-len)
(declare (type bignum-index index))
(multiple-value-bind (next-digit low)
- (%multiply-and-add (%bignum-ref bignum index)
- smallnum
- carry-digit)
- (declare (type bignum-element-type next-digit low))
- (setf carry-digit next-digit)
- (setf (%bignum-ref res index) low)))
+ (%multiply-and-add (%bignum-ref bignum index)
+ smallnum
+ carry-digit)
+ (declare (type bignum-element-type next-digit low))
+ (setf carry-digit next-digit)
+ (setf (%bignum-ref res index) low)))
(setf (%bignum-ref res bignum-len) carry-digit)
(unless bignum-plus-p
(negate-bignum-buffer-in-place bignum bignum-len))
(let ((res-len (%normalize-bignum-buffer res (1+ bignum-len))))
(unless (eq bignum-plus-p smallnum-plus-p)
- (negate-bignum-buffer-in-place res res-len))
+ (negate-bignum-buffer-in-place res res-len))
res-len)))
;;; Given U and V, return U / V mod 2^32. Implements the algorithm in the
(declaim (inline bmod))
(defun bmod (u v)
(let ((ud (%bignum-ref u 0))
- (vd (%bignum-ref v 0))
- (umask 0)
- (imask 1)
- (m 0))
+ (vd (%bignum-ref v 0))
+ (umask 0)
+ (imask 1)
+ (m 0))
(declare (type (unsigned-byte #.sb!vm:n-word-bits) ud vd umask imask m))
(dotimes (i digit-size)
(setf umask (logior umask imask))
- (unless (zerop (logand ud umask))
- (setf ud (M (- ud vd)))
- (setf m (M (logior m imask))))
- (setf imask (M (ash imask 1)))
- (setf vd (M (ash vd 1))))
+ (when (logtest ud umask)
+ (setf ud (modularly (- ud vd)))
+ (setf m (modularly (logior m imask))))
+ (setf imask (modularly (ash imask 1)))
+ (setf vd (modularly (ash vd 1))))
m))
(defun dmod (u u-len v v-len tmp1)
(loop while (> (bignum-buffer-integer-length u u-len)
- (+ (bignum-buffer-integer-length v v-len)
- digit-size))
+ (+ (bignum-buffer-integer-length v v-len)
+ digit-size))
do
(unless (zerop (%bignum-ref u 0))
(let* ((bmod (bmod u v))
- (tmp1-len (multiply-bignum-buffer-and-smallnum-to-buffer v v-len
- bmod
- tmp1)))
- (setf u-len (subtract-bignum-buffers u u-len
- tmp1 tmp1-len
- u))
- (bignum-abs-buffer u u-len)))
+ (tmp1-len (multiply-bignum-buffer-and-smallnum-to-buffer v v-len
+ bmod
+ tmp1)))
+ (setf u-len (subtract-bignum-buffers u u-len
+ tmp1 tmp1-len
+ u))
+ (bignum-abs-buffer u u-len)))
(gcd-assert (zerop (%bignum-ref u 0)))
(setf u-len (bignum-buffer-ashift-right u u-len digit-size)))
(let* ((d (+ 1 (- (bignum-buffer-integer-length u u-len)
- (bignum-buffer-integer-length v v-len))))
- (n (1- (ash 1 d))))
+ (bignum-buffer-integer-length v v-len))))
+ (n (1- (ash 1 d))))
(declare (type (unsigned-byte #.(integer-length #.sb!vm:n-word-bits)) d)
- (type (unsigned-byte #.sb!vm:n-word-bits) n))
+ (type (unsigned-byte #.sb!vm:n-word-bits) n))
(gcd-assert (>= d 0))
- (unless (zerop (logand (%bignum-ref u 0) n))
+ (when (logtest (%bignum-ref u 0) n)
(let ((tmp1-len
- (multiply-bignum-buffer-and-smallnum-to-buffer v v-len
- (logand n (bmod u
- v))
- tmp1)))
- (setf u-len (subtract-bignum-buffers u u-len
- tmp1 tmp1-len
- u))
- (bignum-abs-buffer u u-len)))
+ (multiply-bignum-buffer-and-smallnum-to-buffer v v-len
+ (logand n (bmod u
+ v))
+ tmp1)))
+ (setf u-len (subtract-bignum-buffers u u-len
+ tmp1 tmp1-len
+ u))
+ (bignum-abs-buffer u u-len)))
u-len))
(defconstant lower-ones-digit (1- (ash 1 (truncate sb!vm:n-word-bits 2))))
-
+
;;; Find D and N such that (LOGAND ALL-ONES-DIGIT (- (* D X) (* N Y))) is 0,
;;; (< 0 N LOWER-ONES-DIGIT) and (< 0 (ABS D) LOWER-ONES-DIGIT).
(defun reduced-ratio-mod (x y)
(let* ((c (bmod x y))
- (n1 c)
- (d1 1)
- (n2 (M (1+ (M (lognot n1)))))
- (d2 (M -1)))
+ (n1 c)
+ (d1 1)
+ (n2 (modularly (1+ (modularly (lognot n1)))))
+ (d2 (modularly -1)))
(declare (type (unsigned-byte #.sb!vm:n-word-bits) n1 d1 n2 d2))
(loop while (> n2 (expt 2 (truncate digit-size 2))) do
- (loop for i of-type (mod #.sb!vm:n-word-bits)
- downfrom (- (integer-length n1) (integer-length n2))
- while (>= n1 n2) do
- (when (>= n1 (M (ash n2 i)))
- (psetf n1 (M (- n1 (M (ash n2 i))))
- d1 (M (- d1 (M (ash d2 i)))))))
- (psetf n1 n2
- d1 d2
- n2 n1
- d2 d1))
+ (loop for i of-type (mod #.sb!vm:n-word-bits)
+ downfrom (- (integer-length n1) (integer-length n2))
+ while (>= n1 n2) do
+ (when (>= n1 (modularly (ash n2 i)))
+ (psetf n1 (modularly (- n1 (modularly (ash n2 i))))
+ d1 (modularly (- d1 (modularly (ash d2 i)))))))
+ (psetf n1 n2
+ d1 d2
+ n2 n1
+ d2 d1))
(values n2 (if (>= d2 (expt 2 (1- digit-size)))
- (lognot (logand most-positive-fixnum (lognot d2)))
- (logand lower-ones-digit d2)))))
+ (lognot (logand most-positive-fixnum (lognot d2)))
+ (logand lower-ones-digit d2)))))
(defun copy-bignum (a &optional (len (%bignum-length a)))
(bignum-replace b a)
(%bignum-set-length b len)
b))
-
+
;;; Allocate a single word bignum that holds fixnum. This is useful when
;;; we are trying to mix fixnum and bignum operands.
#!-sb-fluid (declaim (inline make-small-bignum))
res))
;; When the larger number is less than this many bignum digits long, revert
-;; to old algorithm.
+;; to old algorithm.
(defparameter *accelerated-gcd-cutoff* 3)
;;; Alternate between k-ary reduction with the help of
(defun bignum-gcd (u0 v0)
(declare (type bignum-type u0 v0))
(let* ((u1 (if (%bignum-0-or-plusp u0 (%bignum-length u0))
- u0
- (negate-bignum u0 nil)))
- (v1 (if (%bignum-0-or-plusp v0 (%bignum-length v0))
- v0
- (negate-bignum v0 nil))))
+ u0
+ (negate-bignum u0 nil)))
+ (v1 (if (%bignum-0-or-plusp v0 (%bignum-length v0))
+ v0
+ (negate-bignum v0 nil))))
(if (zerop v1)
- (return-from bignum-gcd u1))
+ (return-from bignum-gcd u1))
(when (> u1 v1)
(rotatef u1 v1))
(let ((n (mod v1 u1)))
(setf v1 (if (fixnump n)
- (make-small-bignum n)
- n)))
+ (make-small-bignum n)
+ n)))
(if (and (= 1 (%bignum-length v1))
- (zerop (%bignum-ref v1 0)))
- (return-from bignum-gcd (%normalize-bignum u1
- (%bignum-length u1))))
+ (zerop (%bignum-ref v1 0)))
+ (return-from bignum-gcd (%normalize-bignum u1
+ (%bignum-length u1))))
(let* ((buffer-len (+ 2 (%bignum-length u1)))
- (u (%allocate-bignum buffer-len))
- (u-len (%bignum-length u1))
- (v (%allocate-bignum buffer-len))
- (v-len (%bignum-length v1))
- (tmp1 (%allocate-bignum buffer-len))
- (tmp1-len 0)
- (tmp2 (%allocate-bignum buffer-len))
- (tmp2-len 0)
- (factors-of-two
- (bignum-factors-of-two u1 (%bignum-length u1)
- v1 (%bignum-length v1))))
+ (u (%allocate-bignum buffer-len))
+ (u-len (%bignum-length u1))
+ (v (%allocate-bignum buffer-len))
+ (v-len (%bignum-length v1))
+ (tmp1 (%allocate-bignum buffer-len))
+ (tmp1-len 0)
+ (tmp2 (%allocate-bignum buffer-len))
+ (tmp2-len 0)
+ (factors-of-two
+ (bignum-factors-of-two u1 (%bignum-length u1)
+ v1 (%bignum-length v1))))
(declare (type (or null bignum-index)
- buffer-len u-len v-len tmp1-len tmp2-len))
+ buffer-len u-len v-len tmp1-len tmp2-len))
(bignum-replace u u1)
(bignum-replace v v1)
(setf u-len
- (make-gcd-bignum-odd u
- (bignum-buffer-ashift-right u u-len
- factors-of-two)))
+ (make-gcd-bignum-odd u
+ (bignum-buffer-ashift-right u u-len
+ factors-of-two)))
(setf v-len
- (make-gcd-bignum-odd v
- (bignum-buffer-ashift-right v v-len
- factors-of-two)))
+ (make-gcd-bignum-odd v
+ (bignum-buffer-ashift-right v v-len
+ factors-of-two)))
(loop until (or (< u-len *accelerated-gcd-cutoff*)
- (not v-len)
- (zerop v-len)
- (and (= 1 v-len)
- (zerop (%bignum-ref v 0))))
- do
- (gcd-assert (= buffer-len (%bignum-length u)
- (%bignum-length v)
- (%bignum-length tmp1)
- (%bignum-length tmp2)))
- (if (> (bignum-buffer-integer-length u u-len)
- (+ #.(truncate sb!vm:n-word-bits 4)
- (bignum-buffer-integer-length v v-len)))
- (setf u-len (dmod u u-len
- v v-len
- tmp1))
- (multiple-value-bind (n d) (reduced-ratio-mod u v)
- (setf tmp1-len
- (multiply-bignum-buffer-and-smallnum-to-buffer v v-len
- n tmp1))
- (setf tmp2-len
- (multiply-bignum-buffer-and-smallnum-to-buffer u u-len
- d tmp2))
- (gcd-assert (= (copy-bignum tmp2 tmp2-len)
- (* (copy-bignum u u-len) d)))
- (gcd-assert (= (copy-bignum tmp1 tmp1-len)
- (* (copy-bignum v v-len) n)))
- (setf u-len
- (subtract-bignum-buffers-with-len tmp1 tmp1-len
- tmp2 tmp2-len
- u
- (1+ (max tmp1-len
- tmp2-len))))
- (gcd-assert (or (zerop (- (copy-bignum tmp1 tmp1-len)
- (copy-bignum tmp2 tmp2-len)))
- (= (copy-bignum u u-len)
- (- (copy-bignum tmp1 tmp1-len)
- (copy-bignum tmp2 tmp2-len)))))
- (bignum-abs-buffer u u-len)
- (gcd-assert (zerop (M u)))))
- (setf u-len (make-gcd-bignum-odd u u-len))
- (rotatef u v)
- (rotatef u-len v-len))
+ (not v-len)
+ (zerop v-len)
+ (and (= 1 v-len)
+ (zerop (%bignum-ref v 0))))
+ do
+ (gcd-assert (= buffer-len (%bignum-length u)
+ (%bignum-length v)
+ (%bignum-length tmp1)
+ (%bignum-length tmp2)))
+ (if (> (bignum-buffer-integer-length u u-len)
+ (+ #.(truncate sb!vm:n-word-bits 4)
+ (bignum-buffer-integer-length v v-len)))
+ (setf u-len (dmod u u-len
+ v v-len
+ tmp1))
+ (multiple-value-bind (n d) (reduced-ratio-mod u v)
+ (setf tmp1-len
+ (multiply-bignum-buffer-and-smallnum-to-buffer v v-len
+ n tmp1))
+ (setf tmp2-len
+ (multiply-bignum-buffer-and-smallnum-to-buffer u u-len
+ d tmp2))
+ (gcd-assert (= (copy-bignum tmp2 tmp2-len)
+ (* (copy-bignum u u-len) d)))
+ (gcd-assert (= (copy-bignum tmp1 tmp1-len)
+ (* (copy-bignum v v-len) n)))
+ (setf u-len
+ (subtract-bignum-buffers-with-len tmp1 tmp1-len
+ tmp2 tmp2-len
+ u
+ (1+ (max tmp1-len
+ tmp2-len))))
+ (gcd-assert (or (zerop (- (copy-bignum tmp1 tmp1-len)
+ (copy-bignum tmp2 tmp2-len)))
+ (= (copy-bignum u u-len)
+ (- (copy-bignum tmp1 tmp1-len)
+ (copy-bignum tmp2 tmp2-len)))))
+ (bignum-abs-buffer u u-len)
+ (gcd-assert (zerop (modularly u)))))
+ (setf u-len (make-gcd-bignum-odd u u-len))
+ (rotatef u v)
+ (rotatef u-len v-len))
+ (bignum-abs-buffer u u-len)
(setf u (copy-bignum u u-len))
- (let ((n (bignum-mod-gcd v1 u)))
- (ash (bignum-mod-gcd u1 (if (fixnump n)
- (make-small-bignum n)
- n))
- factors-of-two)))))
+ (let ((n (bignum-mod-gcd v1 u)))
+ (ash (bignum-mod-gcd u1 (if (fixnump n)
+ (make-small-bignum n)
+ n))
+ factors-of-two)))))
(defun bignum-mod-gcd (a b)
(declare (type bignum-type a b))
;; A and B pretty quickly). After that, use the binary GCD
;; algorithm to handle the rest.
(loop until (and (= (%bignum-length b) 1) (zerop (%bignum-ref b 0))) do
- (when (<= (%bignum-length a) (1+ (%bignum-length b)))
- (return-from bignum-mod-gcd (bignum-binary-gcd a b)))
- (let ((rem (mod a b)))
- (if (fixnump rem)
- (setf a (make-small-bignum rem))
- (setf a rem))
- (rotatef a b)))
+ (when (<= (%bignum-length a) (1+ (%bignum-length b)))
+ (return-from bignum-mod-gcd (bignum-binary-gcd a b)))
+ (let ((rem (mod a b)))
+ (if (fixnump rem)
+ (setf a (make-small-bignum rem))
+ (setf a rem))
+ (rotatef a b)))
(if (= (%bignum-length a) 1)
(%normalize-bignum a 1)
a))
(defun bignum-binary-gcd (a b)
(declare (type bignum-type a b))
(let* ((len-a (%bignum-length a))
- (len-b (%bignum-length b)))
+ (len-b (%bignum-length b)))
(declare (type bignum-index len-a len-b))
(with-bignum-buffers ((a-buffer len-a a)
- (b-buffer len-b b)
- (res-buffer (max len-a len-b)))
+ (b-buffer len-b b)
+ (res-buffer (max len-a len-b)))
(let* ((factors-of-two
- (bignum-factors-of-two a-buffer len-a
- b-buffer len-b))
- (len-a (make-gcd-bignum-odd
- a-buffer
- (bignum-buffer-ashift-right a-buffer len-a
- factors-of-two)))
- (len-b (make-gcd-bignum-odd
- b-buffer
- (bignum-buffer-ashift-right b-buffer len-b
- factors-of-two))))
- (declare (type bignum-index len-a len-b))
- (let ((x a-buffer)
- (len-x len-a)
- (y b-buffer)
- (len-y len-b)
- (z res-buffer))
- (loop
- (multiple-value-bind (u v len-v r len-r)
- (bignum-gcd-order-and-subtract x len-x y len-y z)
- (declare (type bignum-index len-v len-r))
- (when (and (= len-r 1) (zerop (%bignum-ref r 0)))
- (if (zerop factors-of-two)
- (let ((ret (%allocate-bignum len-v)))
- (dotimes (i len-v)
- (setf (%bignum-ref ret i) (%bignum-ref v i)))
- (return (%normalize-bignum ret len-v)))
- (return (bignum-ashift-left v factors-of-two len-v))))
- (setf x v len-x len-v)
- (setf y r len-y (make-gcd-bignum-odd r len-r))
- (setf z u))))))))
+ (bignum-factors-of-two a-buffer len-a
+ b-buffer len-b))
+ (len-a (make-gcd-bignum-odd
+ a-buffer
+ (bignum-buffer-ashift-right a-buffer len-a
+ factors-of-two)))
+ (len-b (make-gcd-bignum-odd
+ b-buffer
+ (bignum-buffer-ashift-right b-buffer len-b
+ factors-of-two))))
+ (declare (type bignum-index len-a len-b))
+ (let ((x a-buffer)
+ (len-x len-a)
+ (y b-buffer)
+ (len-y len-b)
+ (z res-buffer))
+ (loop
+ (multiple-value-bind (u v len-v r len-r)
+ (bignum-gcd-order-and-subtract x len-x y len-y z)
+ (declare (type bignum-index len-v len-r))
+ (when (and (= len-r 1) (zerop (%bignum-ref r 0)))
+ (if (zerop factors-of-two)
+ (let ((ret (%allocate-bignum len-v)))
+ (dotimes (i len-v)
+ (setf (%bignum-ref ret i) (%bignum-ref v i)))
+ (return (%normalize-bignum ret len-v)))
+ (return (bignum-ashift-left v factors-of-two len-v))))
+ (setf x v len-x len-v)
+ (setf y r len-y (make-gcd-bignum-odd r len-r))
+ (setf z u))))))))
(defun bignum-gcd-order-and-subtract (a len-a b len-b res)
(declare (type bignum-index len-a len-b) (type bignum-type a b))
(cond ((= len-a len-b)
- (do ((i (1- len-a) (1- i)))
- ((= i -1)
- (setf (%bignum-ref res 0) 0)
- (values a b len-b res 1))
- (let ((a-digit (%bignum-ref a i))
- (b-digit (%bignum-ref b i)))
- (cond ((%digit-compare a-digit b-digit))
- ((%digit-greater a-digit b-digit)
- (return
- (values a b len-b res
- (subtract-bignum-buffers a len-a b len-b
- res))))
- (t
- (return
- (values b a len-a res
- (subtract-bignum-buffers b len-b
- a len-a
- res))))))))
- ((> len-a len-b)
- (values a b len-b res
- (subtract-bignum-buffers a len-a b len-b res)))
- (t
- (values b a len-a res
- (subtract-bignum-buffers b len-b a len-a res)))))
+ (do ((i (1- len-a) (1- i)))
+ ((= i -1)
+ (setf (%bignum-ref res 0) 0)
+ (values a b len-b res 1))
+ (let ((a-digit (%bignum-ref a i))
+ (b-digit (%bignum-ref b i)))
+ (cond ((%digit-compare a-digit b-digit))
+ ((%digit-greater a-digit b-digit)
+ (return
+ (values a b len-b res
+ (subtract-bignum-buffers a len-a b len-b
+ res))))
+ (t
+ (return
+ (values b a len-a res
+ (subtract-bignum-buffers b len-b
+ a len-a
+ res))))))))
+ ((> len-a len-b)
+ (values a b len-b res
+ (subtract-bignum-buffers a len-a b len-b res)))
+ (t
+ (values b a len-a res
+ (subtract-bignum-buffers b len-b a len-a res)))))
(defun make-gcd-bignum-odd (a len-a)
(declare (type bignum-type a) (type bignum-index len-a))
(dotimes (index len-a)
(declare (type bignum-index index))
(do ((digit (%bignum-ref a index) (%ashr digit 1))
- (increment 0 (1+ increment)))
- ((zerop digit))
+ (increment 0 (1+ increment)))
+ ((zerop digit))
(declare (type (mod #.sb!vm:n-word-bits) increment))
(when (oddp digit)
- (return-from make-gcd-bignum-odd
- (bignum-buffer-ashift-right a len-a
- (+ (* index digit-size)
- increment)))))))
+ (return-from make-gcd-bignum-odd
+ (bignum-buffer-ashift-right a len-a
+ (+ (* index digit-size)
+ increment)))))))
\f
;;;; negation
;;; This negates bignum-len digits of bignum, storing the resulting digits into
;;; result (possibly EQ to bignum) and returning whatever end-carry there is.
-(sb!xc:defmacro bignum-negate-loop (bignum
- bignum-len
- &optional (result nil resultp))
- (let ((carry (gensym))
- (end (gensym))
- (value (gensym))
- (last (gensym)))
+(sb!xc:defmacro bignum-negate-loop
+ (bignum bignum-len &optional (result nil resultp))
+ (with-unique-names (carry end value last)
`(let* (,@(if (not resultp) `(,last))
- (,carry
- (multiple-value-bind (,value ,carry)
- (%add-with-carry (%lognot (%bignum-ref ,bignum 0)) 1 0)
- ,(if resultp
- `(setf (%bignum-ref ,result 0) ,value)
- `(setf ,last ,value))
- ,carry))
- (i 1)
- (,end ,bignum-len))
+ (,carry
+ (multiple-value-bind (,value ,carry)
+ (%add-with-carry (%lognot (%bignum-ref ,bignum 0)) 1 0)
+ ,(if resultp
+ `(setf (%bignum-ref ,result 0) ,value)
+ `(setf ,last ,value))
+ ,carry))
+ (i 1)
+ (,end ,bignum-len))
(declare (type bit ,carry)
- (type bignum-index i ,end))
+ (type bignum-index i ,end))
(loop
- (when (= i ,end) (return))
- (multiple-value-bind (,value temp)
- (%add-with-carry (%lognot (%bignum-ref ,bignum i)) 0 ,carry)
- ,(if resultp
- `(setf (%bignum-ref ,result i) ,value)
- `(setf ,last ,value))
- (setf ,carry temp))
- (incf i))
+ (when (= i ,end) (return))
+ (multiple-value-bind (,value temp)
+ (%add-with-carry (%lognot (%bignum-ref ,bignum i)) 0 ,carry)
+ ,(if resultp
+ `(setf (%bignum-ref ,result i) ,value)
+ `(setf ,last ,value))
+ (setf ,carry temp))
+ (incf i))
,(if resultp carry `(values ,carry ,last)))))
) ; EVAL-WHEN
(defun negate-bignum (x &optional (fully-normalize t))
(declare (type bignum-type x))
(let* ((len-x (%bignum-length x))
- (len-res (1+ len-x))
- (res (%allocate-bignum len-res)))
+ (len-res (1+ len-x))
+ (res (%allocate-bignum len-res)))
(declare (type bignum-index len-x len-res)) ;Test len-res for range?
(let ((carry (bignum-negate-loop x len-x res)))
(setf (%bignum-ref res len-x)
- (%add-with-carry (%lognot (%sign-digit x len-x)) 0 carry)))
+ (%add-with-carry (%lognot (%sign-digit x len-x)) 0 carry)))
(if fully-normalize
- (%normalize-bignum res len-res)
- (%mostly-normalize-bignum res len-res))))
+ (%normalize-bignum res len-res)
+ (%mostly-normalize-bignum res len-res))))
;;; This assumes bignum is positive; that is, the result of negating it will
;;; stay in the provided allocated bignum.
(defun bignum-abs-buffer (bignum len)
(unless (%bignum-0-or-plusp bignum len)
- (negate-bignum-in-place bignum len)))
+ (negate-bignum-buffer-in-place bignum len)))
\f
;;;; shifting
;;; digit from high bits of the i'th source digit and the start-pos number of
;;; bits from the i+1'th source digit.
(sb!xc:defmacro shift-right-unaligned (source
- start-digit
- start-pos
- res-len-form
- termination
- &optional result)
+ start-digit
+ start-pos
+ res-len-form
+ termination
+ &optional result)
`(let* ((high-bits-in-first-digit (- digit-size ,start-pos))
- (res-len ,res-len-form)
- (res-len-1 (1- res-len))
- ,@(if result `((,result (%allocate-bignum res-len)))))
+ (res-len ,res-len-form)
+ (res-len-1 (1- res-len))
+ ,@(if result `((,result (%allocate-bignum res-len)))))
(declare (type bignum-index res-len res-len-1))
- (do ((i ,start-digit i+1)
- (i+1 (1+ ,start-digit) (1+ i+1))
- (j 0 (1+ j)))
- ,termination
- (declare (type bignum-index i i+1 j))
+ (do ((i ,start-digit (1+ i))
+ (j 0 (1+ j)))
+ ,termination
+ (declare (type bignum-index i j))
(setf (%bignum-ref ,(if result result source) j)
- (%logior (%digit-logical-shift-right (%bignum-ref ,source i)
- ,start-pos)
- (%ashl (%bignum-ref ,source i+1)
- high-bits-in-first-digit))))))
+ (%logior (%digit-logical-shift-right (%bignum-ref ,source i)
+ ,start-pos)
+ (%ashl (%bignum-ref ,source (1+ i))
+ high-bits-in-first-digit))))))
) ; EVAL-WHEN
;;; locals established by the macro.
(defun bignum-ashift-right (bignum count)
(declare (type bignum-type bignum)
- (type unsigned-byte count))
+ (type unsigned-byte count))
(let ((bignum-len (%bignum-length bignum)))
(declare (type bignum-index bignum-len))
(cond ((fixnump count)
- (multiple-value-bind (digits n-bits) (truncate count digit-size)
- (declare (type bignum-index digits))
- (cond
- ((>= digits bignum-len)
- (if (%bignum-0-or-plusp bignum bignum-len) 0 -1))
- ((zerop n-bits)
- (bignum-ashift-right-digits bignum digits))
- (t
- (shift-right-unaligned bignum digits n-bits (- bignum-len digits)
- ((= j res-len-1)
- (setf (%bignum-ref res j)
- (%ashr (%bignum-ref bignum i) n-bits))
- (%normalize-bignum res res-len))
- res)))))
- ((> count bignum-len)
- (if (%bignum-0-or-plusp bignum bignum-len) 0 -1))
- ;; Since a FIXNUM should be big enough to address anything in
- ;; memory, including arrays of bits, and since arrays of bits
- ;; take up about the same space as corresponding fixnums, there
- ;; should be no way that we fall through to this case: any shift
- ;; right by a bignum should give zero. But let's check anyway:
- (t (error "bignum overflow: can't shift right by ~S" count)))))
+ (multiple-value-bind (digits n-bits) (truncate count digit-size)
+ (declare (type bignum-index digits))
+ (cond
+ ((>= digits bignum-len)
+ (if (%bignum-0-or-plusp bignum bignum-len) 0 -1))
+ ((zerop n-bits)
+ (bignum-ashift-right-digits bignum digits))
+ (t
+ (shift-right-unaligned bignum digits n-bits (- bignum-len digits)
+ ((= j res-len-1)
+ (setf (%bignum-ref res j)
+ (%ashr (%bignum-ref bignum i) n-bits))
+ (%normalize-bignum res res-len))
+ res)))))
+ ((> count bignum-len)
+ (if (%bignum-0-or-plusp bignum bignum-len) 0 -1))
+ ;; Since a FIXNUM should be big enough to address anything in
+ ;; memory, including arrays of bits, and since arrays of bits
+ ;; take up about the same space as corresponding fixnums, there
+ ;; should be no way that we fall through to this case: any shift
+ ;; right by a bignum should give zero. But let's check anyway:
+ (t (error "bignum overflow: can't shift right by ~S" count)))))
(defun bignum-ashift-right-digits (bignum digits)
(declare (type bignum-type bignum)
- (type bignum-index digits))
+ (type bignum-index digits))
(let* ((res-len (- (%bignum-length bignum) digits))
- (res (%allocate-bignum res-len)))
+ (res (%allocate-bignum res-len)))
(declare (type bignum-index res-len)
- (type bignum-type res))
+ (type bignum-type res))
(bignum-replace res bignum :start2 digits)
(%normalize-bignum res res-len)))
(cond
((zerop n-bits)
(let ((new-end (- bignum-len digits)))
- (bignum-replace bignum bignum :end1 new-end :start2 digits
- :end2 bignum-len)
- (%normalize-bignum-buffer bignum new-end)))
+ (bignum-replace bignum bignum :end1 new-end :start2 digits
+ :end2 bignum-len)
+ (%normalize-bignum-buffer bignum new-end)))
(t
(shift-right-unaligned bignum digits n-bits (- bignum-len digits)
- ((= j res-len-1)
- (setf (%bignum-ref bignum j)
- (%ashr (%bignum-ref bignum i) n-bits))
- (%normalize-bignum-buffer bignum res-len)))))))
+ ((= j res-len-1)
+ (setf (%bignum-ref bignum j)
+ (%ashr (%bignum-ref bignum i) n-bits))
+ (%normalize-bignum-buffer bignum res-len)))))))
;;; This handles shifting a bignum buffer to provide fresh bignum data for some
;;; internal routines. We know bignum is safe when called with bignum-len.
;;; branch handles the general case.
(defun bignum-ashift-left (bignum x &optional bignum-len)
(declare (type bignum-type bignum)
- (type unsigned-byte x)
- (type (or null bignum-index) bignum-len))
+ (type unsigned-byte x)
+ (type (or null bignum-index) bignum-len))
(if (fixnump x)
(multiple-value-bind (digits n-bits) (truncate x digit-size)
(let* ((bignum-len (or bignum-len (%bignum-length bignum)))
- (res-len (+ digits bignum-len 1)))
- (when (> res-len maximum-bignum-length)
- (error "can't represent result of left shift"))
- (if (zerop n-bits)
- (bignum-ashift-left-digits bignum bignum-len digits)
- (bignum-ashift-left-unaligned bignum digits n-bits res-len))))
+ (res-len (+ digits bignum-len 1)))
+ (when (> res-len maximum-bignum-length)
+ (error "can't represent result of left shift"))
+ (if (zerop n-bits)
+ (bignum-ashift-left-digits bignum bignum-len digits)
+ (bignum-ashift-left-unaligned bignum digits n-bits res-len))))
;; Left shift by a number too big to be represented as a fixnum
;; would exceed our memory capacity, since a fixnum is big enough
;; to index any array, including a bit array.
(defun bignum-ashift-left-digits (bignum bignum-len digits)
(declare (type bignum-index bignum-len digits))
(let* ((res-len (+ bignum-len digits))
- (res (%allocate-bignum res-len)))
+ (res (%allocate-bignum res-len)))
(declare (type bignum-index res-len))
(bignum-replace res bignum :start1 digits :end1 res-len :end2 bignum-len
- :from-end t)
+ :from-end t)
res))
;;; BIGNUM-TRUNCATE uses this to store into a bignum buffer by supplying res.
;;; first non-zero result digit, digits. We also grab some left over high
;;; bits from the last digit of bignum.
(defun bignum-ashift-left-unaligned (bignum digits n-bits res-len
- &optional (res nil resp))
+ &optional (res nil resp))
(declare (type bignum-index digits res-len)
- (type (mod #.digit-size) n-bits))
+ (type (mod #.digit-size) n-bits))
(let* ((remaining-bits (- digit-size n-bits))
- (res-len-1 (1- res-len))
- (res (or res (%allocate-bignum res-len))))
+ (res-len-1 (1- res-len))
+ (res (or res (%allocate-bignum res-len))))
(declare (type bignum-index res-len res-len-1))
- (do ((i 0 i+1)
- (i+1 1 (1+ i+1))
- (j (1+ digits) (1+ j)))
- ((= j res-len-1)
- (setf (%bignum-ref res digits)
- (%ashl (%bignum-ref bignum 0) n-bits))
- (setf (%bignum-ref res j)
- (%ashr (%bignum-ref bignum i) remaining-bits))
- (if resp
- (%normalize-bignum-buffer res res-len)
- (%normalize-bignum res res-len)))
- (declare (type bignum-index i i+1 j))
+ (do ((i 0 (1+ i))
+ (j (1+ digits) (1+ j)))
+ ((= j res-len-1)
+ (setf (%bignum-ref res digits)
+ (%ashl (%bignum-ref bignum 0) n-bits))
+ (setf (%bignum-ref res j)
+ (%ashr (%bignum-ref bignum i) remaining-bits))
+ (if resp
+ (%normalize-bignum-buffer res res-len)
+ (%normalize-bignum res res-len)))
+ (declare (type bignum-index i j))
(setf (%bignum-ref res j)
- (%logior (%digit-logical-shift-right (%bignum-ref bignum i)
- remaining-bits)
- (%ashl (%bignum-ref bignum i+1) n-bits))))))
+ (%logior (%digit-logical-shift-right (%bignum-ref bignum i)
+ remaining-bits)
+ (%ashl (%bignum-ref bignum (1+ i)) n-bits))))))
\f
;;;; relational operators
(defun bignum-compare (a b)
(declare (type bignum-type a b))
(let* ((len-a (%bignum-length a))
- (len-b (%bignum-length b))
- (a-plusp (%bignum-0-or-plusp a len-a))
- (b-plusp (%bignum-0-or-plusp b len-b)))
+ (len-b (%bignum-length b))
+ (a-plusp (%bignum-0-or-plusp a len-a))
+ (b-plusp (%bignum-0-or-plusp b len-b)))
(declare (type bignum-index len-a len-b))
(cond ((not (eq a-plusp b-plusp))
- (if a-plusp 1 -1))
- ((= len-a len-b)
- (do ((i (1- len-a) (1- i)))
- (())
- (declare (type bignum-index i))
- (let ((a-digit (%bignum-ref a i))
- (b-digit (%bignum-ref b i)))
- (declare (type bignum-element-type a-digit b-digit))
- (when (%digit-greater a-digit b-digit)
- (return 1))
- (when (%digit-greater b-digit a-digit)
- (return -1)))
- (when (zerop i) (return 0))))
- ((> len-a len-b)
- (if a-plusp 1 -1))
- (t (if a-plusp -1 1)))))
+ (if a-plusp 1 -1))
+ ((= len-a len-b)
+ (do ((i (1- len-a) (1- i)))
+ (())
+ (declare (type bignum-index i))
+ (let ((a-digit (%bignum-ref a i))
+ (b-digit (%bignum-ref b i)))
+ (declare (type bignum-element-type a-digit b-digit))
+ (when (%digit-greater a-digit b-digit)
+ (return 1))
+ (when (%digit-greater b-digit a-digit)
+ (return -1)))
+ (when (zerop i) (return 0))))
+ ((> len-a len-b)
+ (if a-plusp 1 -1))
+ (t (if a-plusp -1 1)))))
\f
;;;; float conversion
(declare (fixnum exp))
(declare (optimize #-sb-xc-host (sb!ext:inhibit-warnings 3)))
(let ((res (dpb exp
- sb!vm:single-float-exponent-byte
- (logandc2 (logand #xffffffff
- (%bignum-ref bits 1))
- sb!vm:single-float-hidden-bit))))
+ sb!vm:single-float-exponent-byte
+ (logandc2 (logand #xffffffff
+ (%bignum-ref bits 1))
+ sb!vm:single-float-hidden-bit))))
(make-single-float
(if plusp
- res
- (logior res (ash -1 sb!vm:float-sign-shift))))))
+ res
+ (logior res (ash -1 sb!vm:float-sign-shift))))))
(defun double-float-from-bits (bits exp plusp)
(declare (fixnum exp))
(declare (optimize #-sb-xc-host (sb!ext:inhibit-warnings 3)))
(let ((hi (dpb exp
- sb!vm:double-float-exponent-byte
- (logandc2 (ecase sb!vm::n-word-bits
- (32 (%bignum-ref bits 2))
- (64 (ash (%bignum-ref bits 1) -32)))
- sb!vm:double-float-hidden-bit)))
- (lo (logand #xffffffff (%bignum-ref bits 1))))
+ sb!vm:double-float-exponent-byte
+ (logandc2 (ecase sb!vm::n-word-bits
+ (32 (%bignum-ref bits 2))
+ (64 (ash (%bignum-ref bits 1) -32)))
+ sb!vm:double-float-hidden-bit)))
+ (lo (logand #xffffffff (%bignum-ref bits 1))))
(make-double-float (if plusp
- hi
- (logior hi (ash -1 sb!vm:float-sign-shift)))
- lo)))
+ hi
+ (logior hi (ash -1 sb!vm:float-sign-shift)))
+ lo)))
#!+(and long-float x86)
(defun long-float-from-bits (bits exp plusp)
(declare (fixnum exp))
;;; approximation.
(defun bignum-to-float (bignum format)
(let* ((plusp (bignum-plus-p bignum))
- (x (if plusp bignum (negate-bignum bignum)))
- (len (bignum-integer-length x))
- (digits (float-format-digits format))
- (keep (+ digits digit-size))
- (shift (- keep len))
- (shifted (if (minusp shift)
- (bignum-ashift-right x (- shift))
- (bignum-ashift-left x shift)))
- (low (%bignum-ref shifted 0))
- (round-bit (ash 1 (1- digit-size))))
+ (x (if plusp bignum (negate-bignum bignum)))
+ (len (bignum-integer-length x))
+ (digits (float-format-digits format))
+ (keep (+ digits digit-size))
+ (shift (- keep len))
+ (shifted (if (minusp shift)
+ (bignum-ashift-right x (- shift))
+ (bignum-ashift-left x shift)))
+ (low (%bignum-ref shifted 0))
+ (round-bit (ash 1 (1- digit-size))))
(declare (type bignum-index len digits keep) (fixnum shift))
(labels ((round-up ()
- (let ((rounded (add-bignums shifted round-bit)))
- (if (> (integer-length rounded) keep)
- (float-from-bits (bignum-ashift-right rounded 1)
- (1+ len))
- (float-from-bits rounded len))))
- (float-from-bits (bits len)
- (declare (type bignum-index len))
- (ecase format
- (single-float
- (single-float-from-bits
- bits
- (check-exponent len sb!vm:single-float-bias
- sb!vm:single-float-normal-exponent-max)
- plusp))
- (double-float
- (double-float-from-bits
- bits
- (check-exponent len sb!vm:double-float-bias
- sb!vm:double-float-normal-exponent-max)
- plusp))
- #!+long-float
- (long-float
- (long-float-from-bits
- bits
- (check-exponent len sb!vm:long-float-bias
- sb!vm:long-float-normal-exponent-max)
- plusp))))
- (check-exponent (exp bias max)
- (declare (type bignum-index len))
- (let ((exp (+ exp bias)))
- (when (> exp max)
- ;; Why a SIMPLE-TYPE-ERROR? Well, this is mainly
- ;; called by COERCE, which requires an error of
- ;; TYPE-ERROR if the conversion can't happen
- ;; (except in certain circumstances when we are
- ;; coercing to a FUNCTION) -- CSR, 2002-09-18
- (error 'simple-type-error
- :format-control "Too large to be represented as a ~S:~% ~S"
- :format-arguments (list format x)
- :expected-type format
- :datum x))
- exp)))
+ (let ((rounded (add-bignums shifted round-bit)))
+ (if (> (integer-length rounded) keep)
+ (float-from-bits (bignum-ashift-right rounded 1)
+ (1+ len))
+ (float-from-bits rounded len))))
+ (float-from-bits (bits len)
+ (declare (type bignum-index len))
+ (ecase format
+ (single-float
+ (single-float-from-bits
+ bits
+ (check-exponent len sb!vm:single-float-bias
+ sb!vm:single-float-normal-exponent-max)
+ plusp))
+ (double-float
+ (double-float-from-bits
+ bits
+ (check-exponent len sb!vm:double-float-bias
+ sb!vm:double-float-normal-exponent-max)
+ plusp))
+ #!+long-float
+ (long-float
+ (long-float-from-bits
+ bits
+ (check-exponent len sb!vm:long-float-bias
+ sb!vm:long-float-normal-exponent-max)
+ plusp))))
+ (check-exponent (exp bias max)
+ (declare (type bignum-index len))
+ (let ((exp (+ exp bias)))
+ (when (> exp max)
+ ;; Why a SIMPLE-TYPE-ERROR? Well, this is mainly
+ ;; called by COERCE, which requires an error of
+ ;; TYPE-ERROR if the conversion can't happen
+ ;; (except in certain circumstances when we are
+ ;; coercing to a FUNCTION) -- CSR, 2002-09-18
+ (error 'simple-type-error
+ :format-control "Too large to be represented as a ~S:~% ~S"
+ :format-arguments (list format x)
+ :expected-type format
+ :datum x))
+ exp)))
(cond
;; Round down if round bit is 0.
- ((zerop (logand round-bit low))
+ ((not (logtest round-bit low))
(float-from-bits shifted len))
;; If only round bit is set, then round to even.
((and (= low round-bit)
- (dotimes (i (- (%bignum-length x) (ceiling keep digit-size))
- t)
- (unless (zerop (%bignum-ref x i)) (return nil))))
+ (dotimes (i (- (%bignum-length x) (ceiling keep digit-size))
+ t)
+ (unless (zerop (%bignum-ref x i)) (return nil))))
(let ((next (%bignum-ref shifted 1)))
- (if (oddp next)
- (round-up)
- (float-from-bits shifted len))))
+ (if (oddp next)
+ (round-up)
+ (float-from-bits shifted len))))
;; Otherwise, round up.
(t
(round-up))))))
(defun bignum-buffer-integer-length (bignum len)
(declare (type bignum-type bignum))
(let* ((len-1 (1- len))
- (digit (%bignum-ref bignum len-1)))
+ (digit (%bignum-ref bignum len-1)))
(declare (type bignum-index len len-1)
- (type bignum-element-type digit))
+ (type bignum-element-type digit))
(+ (integer-length (%fixnum-digit-with-correct-sign digit))
(* len-1 digit-size))))
(let ((len (%bignum-length bignum)))
(declare (type bignum-index len))
(multiple-value-bind (word-index bit-index)
- (floor index digit-size)
+ (floor index digit-size)
(if (>= word-index len)
- (not (bignum-plus-p bignum))
- (not (zerop (logand (%bignum-ref bignum word-index)
- (ash 1 bit-index))))))))
+ (not (bignum-plus-p bignum))
+ (logbitp bit-index (%bignum-ref bignum word-index))))))
(defun bignum-logcount (bignum)
(declare (type bignum-type bignum))
- (let* ((length (%bignum-length bignum))
- (plusp (%bignum-0-or-plusp bignum length))
- (result 0))
+ (let ((length (%bignum-length bignum))
+ (result 0))
(declare (type bignum-index length)
- (fixnum result))
+ (fixnum result))
(do ((index 0 (1+ index)))
- ((= index length) result)
+ ((= index length)
+ (if (%bignum-0-or-plusp bignum length)
+ result
+ (- (* length digit-size) result)))
(let ((digit (%bignum-ref bignum index)))
- (declare (type bignum-element-type digit))
- (incf result (logcount (if plusp digit (%lognot digit))))))))
+ (declare (type bignum-element-type digit))
+ (incf result (logcount digit))))))
\f
;;;; logical operations
(defun bignum-logical-not (a)
(declare (type bignum-type a))
(let* ((len (%bignum-length a))
- (res (%allocate-bignum len)))
+ (res (%allocate-bignum len)))
(declare (type bignum-index len))
(dotimes (i len res)
(declare (type bignum-index i))
(defun bignum-logical-and (a b)
(declare (type bignum-type a b))
(let* ((len-a (%bignum-length a))
- (len-b (%bignum-length b))
- (a-plusp (%bignum-0-or-plusp a len-a))
- (b-plusp (%bignum-0-or-plusp b len-b)))
+ (len-b (%bignum-length b))
+ (a-plusp (%bignum-0-or-plusp a len-a))
+ (b-plusp (%bignum-0-or-plusp b len-b)))
(declare (type bignum-index len-a len-b))
(cond
((< len-a len-b)
(if a-plusp
- (logand-shorter-positive a len-a b (%allocate-bignum len-a))
- (logand-shorter-negative a len-a b len-b (%allocate-bignum len-b))))
+ (logand-shorter-positive a len-a b (%allocate-bignum len-a))
+ (logand-shorter-negative a len-a b len-b (%allocate-bignum len-b))))
((< len-b len-a)
(if b-plusp
- (logand-shorter-positive b len-b a (%allocate-bignum len-b))
- (logand-shorter-negative b len-b a len-a (%allocate-bignum len-a))))
+ (logand-shorter-positive b len-b a (%allocate-bignum len-b))
+ (logand-shorter-negative b len-b a len-a (%allocate-bignum len-a))))
(t (logand-shorter-positive a len-a b (%allocate-bignum len-a))))))
;;; This takes a shorter bignum, a and len-a, that is positive. Because this
;;; sign bits will mask the other bits out of b. The result is len-a big.
(defun logand-shorter-positive (a len-a b res)
(declare (type bignum-type a b res)
- (type bignum-index len-a))
+ (type bignum-index len-a))
(dotimes (i len-a)
(declare (type bignum-index i))
(setf (%bignum-ref res i)
- (%logand (%bignum-ref a i) (%bignum-ref b i))))
+ (%logand (%bignum-ref a i) (%bignum-ref b i))))
(%normalize-bignum res len-a))
;;; This takes a shorter bignum, a and len-a, that is negative. Because this
;;; bits will include any bits from b. The result is len-b big.
(defun logand-shorter-negative (a len-a b len-b res)
(declare (type bignum-type a b res)
- (type bignum-index len-a len-b))
+ (type bignum-index len-a len-b))
(dotimes (i len-a)
(declare (type bignum-index i))
(setf (%bignum-ref res i)
- (%logand (%bignum-ref a i) (%bignum-ref b i))))
+ (%logand (%bignum-ref a i) (%bignum-ref b i))))
(do ((i len-a (1+ i)))
((= i len-b))
(declare (type bignum-index i))
(defun bignum-logical-ior (a b)
(declare (type bignum-type a b))
(let* ((len-a (%bignum-length a))
- (len-b (%bignum-length b))
- (a-plusp (%bignum-0-or-plusp a len-a))
- (b-plusp (%bignum-0-or-plusp b len-b)))
+ (len-b (%bignum-length b))
+ (a-plusp (%bignum-0-or-plusp a len-a))
+ (b-plusp (%bignum-0-or-plusp b len-b)))
(declare (type bignum-index len-a len-b))
(cond
((< len-a len-b)
(if a-plusp
- (logior-shorter-positive a len-a b len-b (%allocate-bignum len-b))
- (logior-shorter-negative a len-a b len-b (%allocate-bignum len-b))))
+ (logior-shorter-positive a len-a b len-b (%allocate-bignum len-b))
+ (logior-shorter-negative a len-a b len-b (%allocate-bignum len-b))))
((< len-b len-a)
(if b-plusp
- (logior-shorter-positive b len-b a len-a (%allocate-bignum len-a))
- (logior-shorter-negative b len-b a len-a (%allocate-bignum len-a))))
+ (logior-shorter-positive b len-b a len-a (%allocate-bignum len-a))
+ (logior-shorter-negative b len-b a len-a (%allocate-bignum len-a))))
(t (logior-shorter-positive a len-a b len-b (%allocate-bignum len-a))))))
;;; This takes a shorter bignum, a and len-a, that is positive. Because this
;;; is len-b long.
(defun logior-shorter-positive (a len-a b len-b res)
(declare (type bignum-type a b res)
- (type bignum-index len-a len-b))
+ (type bignum-index len-a len-b))
(dotimes (i len-a)
(declare (type bignum-index i))
(setf (%bignum-ref res i)
- (%logior (%bignum-ref a i) (%bignum-ref b i))))
+ (%logior (%bignum-ref a i) (%bignum-ref b i))))
(do ((i len-a (1+ i)))
((= i len-b))
(declare (type bignum-index i))
;;; bits will include any bits from b. The result is len-b long.
(defun logior-shorter-negative (a len-a b len-b res)
(declare (type bignum-type a b res)
- (type bignum-index len-a len-b))
+ (type bignum-index len-a len-b))
(dotimes (i len-a)
(declare (type bignum-index i))
(setf (%bignum-ref res i)
- (%logior (%bignum-ref a i) (%bignum-ref b i))))
+ (%logior (%bignum-ref a i) (%bignum-ref b i))))
(do ((i len-a (1+ i))
(sign (%sign-digit a len-a)))
((= i len-b))
(defun bignum-logical-xor (a b)
(declare (type bignum-type a b))
(let ((len-a (%bignum-length a))
- (len-b (%bignum-length b)))
+ (len-b (%bignum-length b)))
(declare (type bignum-index len-a len-b))
(if (< len-a len-b)
- (bignum-logical-xor-aux a len-a b len-b (%allocate-bignum len-b))
- (bignum-logical-xor-aux b len-b a len-a (%allocate-bignum len-a)))))
+ (bignum-logical-xor-aux a len-a b len-b (%allocate-bignum len-b))
+ (bignum-logical-xor-aux b len-b a len-a (%allocate-bignum len-a)))))
;;; This takes the shorter of two bignums in a and len-a. Res is len-b
;;; long. Do the XOR.
(defun bignum-logical-xor-aux (a len-a b len-b res)
(declare (type bignum-type a b res)
- (type bignum-index len-a len-b))
+ (type bignum-index len-a len-b))
(dotimes (i len-a)
(declare (type bignum-index i))
(setf (%bignum-ref res i)
- (%logxor (%bignum-ref a i) (%bignum-ref b i))))
+ (%logxor (%bignum-ref a i) (%bignum-ref b i))))
(do ((i len-a (1+ i))
(sign (%sign-digit a len-a)))
((= i len-b))
(setf (%bignum-ref res i) (%logxor sign (%bignum-ref b i))))
(%normalize-bignum res len-b))
\f
-;;;; LDB (load byte)
-
-#|
-FOR NOW WE DON'T USE LDB OR DPB. WE USE SHIFTS AND MASKS IN NUMBERS.LISP WHICH
-IS LESS EFFICIENT BUT EASIER TO MAINTAIN. BILL SAYS THIS CODE CERTAINLY WORKS!
-
-(defconstant maximum-fixnum-bits (- sb!vm:n-word-bits sb!vm:n-lowtag-bits))
-
-(defun bignum-load-byte (byte bignum)
- (declare (type bignum-type bignum))
- (let ((byte-len (byte-size byte))
- (byte-pos (byte-position byte)))
- (if (< byte-len maximum-fixnum-bits)
- (bignum-ldb-fixnum-res bignum byte-len byte-pos)
- (bignum-ldb-bignum-res bignum byte-len byte-pos))))
-
-;;; This returns a fixnum result of loading a byte from a bignum. In order, we
-;;; check for the following conditions:
-;;; Insufficient bignum digits to start loading a byte --
-;;; Return 0 or byte-len 1's depending on sign of bignum.
-;;; One bignum digit containing the whole byte spec --
-;;; Grab 'em, shift 'em, and mask out what we don't want.
-;;; Insufficient bignum digits to cover crossing a digit boundary --
-;;; Grab the available bits in the last digit, and or in whatever
-;;; virtual sign bits we need to return a full byte spec.
-;;; Else (we cross a digit boundary with all bits available) --
-;;; Make a couple masks, grab what we want, shift it around, and
-;;; LOGIOR it all together.
-;;; Because (< maximum-fixnum-bits digit-size) and
-;;; (< byte-len maximum-fixnum-bits),
-;;; we only cross one digit boundary if any.
-(defun bignum-ldb-fixnum-res (bignum byte-len byte-pos)
- (multiple-value-bind (skipped-digits pos) (truncate byte-pos digit-size)
- (let ((bignum-len (%bignum-length bignum))
- (s-digits+1 (1+ skipped-digits)))
- (declare (type bignum-index bignum-len s-digits+1))
- (if (>= skipped-digits bignum-len)
- (if (%bignum-0-or-plusp bignum bignum-len)
- 0
- (%make-ones byte-len))
- (let ((end (+ pos byte-len)))
- (cond ((<= end digit-size)
- (logand (ash (%bignum-ref bignum skipped-digits) (- pos))
- ;; Must LOGAND after shift here.
- (%make-ones byte-len)))
- ((>= s-digits+1 bignum-len)
- (let* ((available-bits (- digit-size pos))
- (res (logand (ash (%bignum-ref bignum skipped-digits)
- (- pos))
- ;; LOGAND should be unnecessary here
- ;; with a logical right shift or a
- ;; correct digit-sized one.
- (%make-ones available-bits))))
- (if (%bignum-0-or-plusp bignum bignum-len)
- res
- (logior (%ashl (%make-ones (- end digit-size))
- available-bits)
- res))))
- (t
- (let* ((high-bits-in-first-digit (- digit-size pos))
- (high-mask (%make-ones high-bits-in-first-digit))
- (low-bits-in-next-digit (- end digit-size))
- (low-mask (%make-ones low-bits-in-next-digit)))
- (declare (type bignum-element-type high-mask low-mask))
- (logior (%ashl (logand (%bignum-ref bignum s-digits+1)
- low-mask)
- high-bits-in-first-digit)
- (logand (ash (%bignum-ref bignum skipped-digits)
- (- pos))
- ;; LOGAND should be unnecessary here with
- ;; a logical right shift or a correct
- ;; digit-sized one.
- high-mask))))))))))
-
-;;; This returns a bignum result of loading a byte from a bignum. In order, we
-;;; check for the following conditions:
-;;; Insufficient bignum digits to start loading a byte --
-;;; Byte-pos starting on a digit boundary --
-;;; Byte spec contained in one bignum digit --
-;;; Grab the bits we want and stick them in a single digit result.
-;;; Since we know byte-pos is non-zero here, we know our single digit
-;;; will have a zero high sign bit.
-;;; Else (unaligned multiple digits) --
-;;; This is like doing a shift right combined with either masking
-;;; out unwanted high bits from bignum or filling in virtual sign
-;;; bits if bignum had insufficient bits. We use SHIFT-RIGHT-ALIGNED
-;;; and reference lots of local variables this macro establishes.
-(defun bignum-ldb-bignum-res (bignum byte-len byte-pos)
- (multiple-value-bind (skipped-digits pos) (truncate byte-pos digit-size)
- (let ((bignum-len (%bignum-length bignum)))
- (declare (type bignum-index bignum-len))
- (cond
- ((>= skipped-digits bignum-len)
- (make-bignum-virtual-ldb-bits bignum bignum-len byte-len))
- ((zerop pos)
- (make-aligned-ldb-bignum bignum bignum-len byte-len skipped-digits))
- ((< (+ pos byte-len) digit-size)
- (let ((res (%allocate-bignum 1)))
- (setf (%bignum-ref res 0)
- (logand (%ashr (%bignum-ref bignum skipped-digits) pos)
- (%make-ones byte-len)))
- res))
- (t
- (make-unaligned-ldb-bignum bignum bignum-len
- byte-len skipped-digits pos))))))
-
-;;; This returns bits from bignum that don't physically exist. These are
-;;; all zero or one depending on the sign of the bignum.
-(defun make-bignum-virtual-ldb-bits (bignum bignum-len byte-len)
- (if (%bignum-0-or-plusp bignum bignum-len)
- 0
- (multiple-value-bind (res-len-1 extra) (truncate byte-len digit-size)
- (declare (type bignum-index res-len-1))
- (let* ((res-len (1+ res-len-1))
- (res (%allocate-bignum res-len)))
- (declare (type bignum-index res-len))
- (do ((j 0 (1+ j)))
- ((= j res-len-1)
- (setf (%bignum-ref res j) (%make-ones extra))
- (%normalize-bignum res res-len))
- (declare (type bignum-index j))
- (setf (%bignum-ref res j) all-ones-digit))))))
-
-;;; Since we are picking up aligned digits, we just copy the whole digits
-;;; we want and fill in extra bits. We might have a byte-len that extends
-;;; off the end of the bignum, so we may have to fill in extra 1's if the
-;;; bignum is negative.
-(defun make-aligned-ldb-bignum (bignum bignum-len byte-len skipped-digits)
- (multiple-value-bind (res-len-1 extra) (truncate byte-len digit-size)
- (declare (type bignum-index res-len-1))
- (let* ((res-len (1+ res-len-1))
- (res (%allocate-bignum res-len)))
- (declare (type bignum-index res-len))
- (do ((i skipped-digits (1+ i))
- (j 0 (1+ j)))
- ((or (= j res-len-1) (= i bignum-len))
- (cond ((< i bignum-len)
- (setf (%bignum-ref res j)
- (logand (%bignum-ref bignum i)
- (the bignum-element-type (%make-ones extra)))))
- ((%bignum-0-or-plusp bignum bignum-len))
- (t
- (do ((j j (1+ j)))
- ((= j res-len-1)
- (setf (%bignum-ref res j) (%make-ones extra)))
- (setf (%bignum-ref res j) all-ones-digit))))
- (%normalize-bignum res res-len))
- (declare (type bignum-index i j))
- (setf (%bignum-ref res j) (%bignum-ref bignum i))))))
-
-;;; This grabs unaligned bignum bits from bignum assuming byte-len causes at
-;;; least one digit boundary crossing. We use SHIFT-RIGHT-UNALIGNED referencing
-;;; lots of local variables established by it.
-(defun make-unaligned-ldb-bignum (bignum
- bignum-len
- byte-len
- skipped-digits
- pos)
- (multiple-value-bind (res-len-1 extra) (truncate byte-len digit-size)
- (shift-right-unaligned
- bignum skipped-digits pos (1+ res-len-1)
- ((or (= j res-len-1) (= i+1 bignum-len))
- (cond ((= j res-len-1)
- (cond
- ((< extra high-bits-in-first-digit)
- (setf (%bignum-ref res j)
- (logand (ash (%bignum-ref bignum i) minus-start-pos)
- ;; Must LOGAND after shift here.
- (%make-ones extra))))
- (t
- (setf (%bignum-ref res j)
- (logand (ash (%bignum-ref bignum i) minus-start-pos)
- ;; LOGAND should be unnecessary here with a logical
- ;; right shift or a correct digit-sized one.
- high-mask))
- (when (%bignum-0-or-plusp bignum bignum-len)
- (setf (%bignum-ref res j)
- (logior (%bignum-ref res j)
- (%ashl (%make-ones
- (- extra high-bits-in-first-digit))
- high-bits-in-first-digit)))))))
- (t
- (setf (%bignum-ref res j)
- (logand (ash (%bignum-ref bignum i) minus-start-pos)
- ;; LOGAND should be unnecessary here with a logical
- ;; right shift or a correct digit-sized one.
- high-mask))
- (unless (%bignum-0-or-plusp bignum bignum-len)
- ;; Fill in upper half of this result digit with 1's.
- (setf (%bignum-ref res j)
- (logior (%bignum-ref res j)
- (%ashl low-mask high-bits-in-first-digit)))
- ;; Fill in any extra 1's we need to be byte-len long.
- (do ((j (1+ j) (1+ j)))
- ((>= j res-len-1)
- (setf (%bignum-ref res j) (%make-ones extra)))
- (setf (%bignum-ref res j) all-ones-digit)))))
- (%normalize-bignum res res-len))
- res)))
-\f
-;;;; DPB (deposit byte)
-
-(defun bignum-deposit-byte (new-byte byte-spec bignum)
- (declare (type bignum-type bignum))
- (let* ((byte-len (byte-size byte-spec))
- (byte-pos (byte-position byte-spec))
- (bignum-len (%bignum-length bignum))
- (bignum-plusp (%bignum-0-or-plusp bignum bignum-len))
- (byte-end (+ byte-pos byte-len))
- (res-len (1+ (max (ceiling byte-end digit-size) bignum-len)))
- (res (%allocate-bignum res-len)))
- (declare (type bignum-index bignum-len res-len))
- ;; Fill in an extra sign digit in case we set what would otherwise be the
- ;; last digit's last bit. Normalize at the end in case this was
- ;; unnecessary.
- (unless bignum-plusp
- (setf (%bignum-ref res (1- res-len)) all-ones-digit))
- (multiple-value-bind (end-digit end-bits) (truncate byte-end digit-size)
- (declare (type bignum-index end-digit))
- ;; Fill in bits from bignum up to byte-pos.
- (multiple-value-bind (pos-digit pos-bits) (truncate byte-pos digit-size)
- (declare (type bignum-index pos-digit))
- (do ((i 0 (1+ i))
- (end (min pos-digit bignum-len)))
- ((= i end)
- (cond ((< i bignum-len)
- (unless (zerop pos-bits)
- (setf (%bignum-ref res i)
- (logand (%bignum-ref bignum i)
- (%make-ones pos-bits)))))
- (bignum-plusp)
- (t
- (do ((i i (1+ i)))
- ((= i pos-digit)
- (unless (zerop pos-bits)
- (setf (%bignum-ref res i) (%make-ones pos-bits))))
- (setf (%bignum-ref res i) all-ones-digit)))))
- (setf (%bignum-ref res i) (%bignum-ref bignum i)))
- ;; Fill in bits from new-byte.
- (if (typep new-byte 'fixnum)
- (deposit-fixnum-bits new-byte byte-len pos-digit pos-bits
- end-digit end-bits res)
- (deposit-bignum-bits new-byte byte-len pos-digit pos-bits
- end-digit end-bits res)))
- ;; Fill in remaining bits from bignum after byte-spec.
- (when (< end-digit bignum-len)
- (setf (%bignum-ref res end-digit)
- (logior (logand (%bignum-ref bignum end-digit)
- (%ashl (%make-ones (- digit-size end-bits))
- end-bits))
- ;; DEPOSIT-FIXNUM-BITS and DEPOSIT-BIGNUM-BITS only store
- ;; bits from new-byte into res's end-digit element, so
- ;; we don't need to mask out unwanted high bits.
- (%bignum-ref res end-digit)))
- (do ((i (1+ end-digit) (1+ i)))
- ((= i bignum-len))
- (setf (%bignum-ref res i) (%bignum-ref bignum i)))))
- (%normalize-bignum res res-len)))
-
-;;; This starts at result's pos-digit skipping pos-bits, and it stores bits
-;;; from new-byte, a fixnum, into result. It effectively stores byte-len
-;;; number of bits, but never stores past end-digit and end-bits in result.
-;;; The first branch fires when all the bits we want from new-byte are present;
-;;; if byte-len crosses from the current result digit into the next, the last
-;;; argument to DEPOSIT-FIXNUM-DIGIT is a mask for those bits. The second
-;;; branch handles the need to grab more bits than the fixnum new-byte has, but
-;;; new-byte is positive; therefore, any virtual bits are zero. The mask for
-;;; bits that don't fit in the current result digit is simply the remaining
-;;; bits in the bignum digit containing new-byte; we don't care if we store
-;;; some extra in the next result digit since they will be zeros. The last
-;;; branch handles the need to grab more bits than the fixnum new-byte has, but
-;;; new-byte is negative; therefore, any virtual bits must be explicitly filled
-;;; in as ones. We call DEPOSIT-FIXNUM-DIGIT to grab what bits actually exist
-;;; and to fill in the current result digit.
-(defun deposit-fixnum-bits (new-byte byte-len pos-digit pos-bits
- end-digit end-bits result)
- (declare (type bignum-index pos-digit end-digit))
- (let ((other-bits (- digit-size pos-bits))
- (new-byte-digit (%fixnum-to-digit new-byte)))
- (declare (type bignum-element-type new-byte-digit))
- (cond ((< byte-len maximum-fixnum-bits)
- (deposit-fixnum-digit new-byte-digit byte-len pos-digit pos-bits
- other-bits result
- (- byte-len other-bits)))
- ((or (plusp new-byte) (zerop new-byte))
- (deposit-fixnum-digit new-byte-digit byte-len pos-digit pos-bits
- other-bits result pos-bits))
- (t
- (multiple-value-bind (digit bits)
- (deposit-fixnum-digit new-byte-digit byte-len pos-digit pos-bits
- other-bits result
- (if (< (- byte-len other-bits) digit-size)
- (- byte-len other-bits)
- digit-size))
- (declare (type bignum-index digit))
- (cond ((< digit end-digit)
- (setf (%bignum-ref result digit)
- (logior (%bignum-ref result digit)
- (%ashl (%make-ones (- digit-size bits)) bits)))
- (do ((i (1+ digit) (1+ i)))
- ((= i end-digit)
- (setf (%bignum-ref result i) (%make-ones end-bits)))
- (setf (%bignum-ref result i) all-ones-digit)))
- ((> digit end-digit))
- ((< bits end-bits)
- (setf (%bignum-ref result digit)
- (logior (%bignum-ref result digit)
- (%ashl (%make-ones (- end-bits bits))
- bits))))))))))
-
-;;; This fills in the current result digit from new-byte-digit. The first case
-;;; handles everything we want fitting in the current digit, and other-bits is
-;;; the number of bits remaining to be filled in result's current digit. This
-;;; number is digit-size minus pos-bits. The second branch handles filling in
-;;; result's current digit, and it shoves the unused bits of new-byte-digit
-;;; into the next result digit. This is correct regardless of new-byte-digit's
-;;; sign. It returns the new current result digit and how many bits already
-;;; filled in the result digit.
-(defun deposit-fixnum-digit (new-byte-digit byte-len pos-digit pos-bits
- other-bits result next-digit-bits-needed)
- (declare (type bignum-index pos-digit)
- (type bignum-element-type new-byte-digit next-digit-mask))
- (cond ((<= byte-len other-bits)
- ;; Bits from new-byte fit in the current result digit.
- (setf (%bignum-ref result pos-digit)
- (logior (%bignum-ref result pos-digit)
- (%ashl (logand new-byte-digit (%make-ones byte-len))
- pos-bits)))
- (if (= byte-len other-bits)
- (values (1+ pos-digit) 0)
- (values pos-digit (+ byte-len pos-bits))))
- (t
- ;; Some of new-byte's bits go in current result digit.
- (setf (%bignum-ref result pos-digit)
- (logior (%bignum-ref result pos-digit)
- (%ashl (logand new-byte-digit (%make-ones other-bits))
- pos-bits)))
- (let ((pos-digit+1 (1+ pos-digit)))
- ;; The rest of new-byte's bits go in the next result digit.
- (setf (%bignum-ref result pos-digit+1)
- (logand (ash new-byte-digit (- other-bits))
- ;; Must LOGAND after shift here.
- (%make-ones next-digit-bits-needed)))
- (if (= next-digit-bits-needed digit-size)
- (values (1+ pos-digit+1) 0)
- (values pos-digit+1 next-digit-bits-needed))))))
-
-;;; This starts at result's pos-digit skipping pos-bits, and it stores bits
-;;; from new-byte, a bignum, into result. It effectively stores byte-len
-;;; number of bits, but never stores past end-digit and end-bits in result.
-;;; When handling a starting bit unaligned with a digit boundary, we check
-;;; in the second branch for the byte spec fitting into the pos-digit element
-;;; after after pos-bits; DEPOSIT-UNALIGNED-BIGNUM-BITS expects at least one
-;;; digit boundary crossing.
-(defun deposit-bignum-bits (bignum-byte byte-len pos-digit pos-bits
- end-digit end-bits result)
- (declare (type bignum-index pos-digit end-digit))
- (cond ((zerop pos-bits)
- (deposit-aligned-bignum-bits bignum-byte pos-digit end-digit end-bits
- result))
- ((or (= end-digit pos-digit)
- (and (= end-digit (1+ pos-digit))
- (zerop end-bits)))
- (setf (%bignum-ref result pos-digit)
- (logior (%bignum-ref result pos-digit)
- (%ashl (logand (%bignum-ref bignum-byte 0)
- (%make-ones byte-len))
- pos-bits))))
- (t (deposit-unaligned-bignum-bits bignum-byte pos-digit pos-bits
- end-digit end-bits result))))
-
-;;; This deposits bits from bignum-byte into result starting at pos-digit and
-;;; the zero'th bit. It effectively only stores bits to end-bits in the
-;;; end-digit element of result. The loop termination code takes care of
-;;; picking up the last digit's bits or filling in virtual negative sign bits.
-(defun deposit-aligned-bignum-bits (bignum-byte pos-digit end-digit end-bits
- result)
- (declare (type bignum-index pos-digit end-digit))
- (let* ((bignum-len (%bignum-length bignum-byte))
- (bignum-plusp (%bignum-0-or-plusp bignum-byte bignum-len)))
- (declare (type bignum-index bignum-len))
- (do ((i 0 (1+ i ))
- (j pos-digit (1+ j)))
- ((or (= j end-digit) (= i bignum-len))
- (cond ((= j end-digit)
- (cond ((< i bignum-len)
- (setf (%bignum-ref result j)
- (logand (%bignum-ref bignum-byte i)
- (%make-ones end-bits))))
- (bignum-plusp)
- (t
- (setf (%bignum-ref result j) (%make-ones end-bits)))))
- (bignum-plusp)
- (t
- (do ((j j (1+ j)))
- ((= j end-digit)
- (setf (%bignum-ref result j) (%make-ones end-bits)))
- (setf (%bignum-ref result j) all-ones-digit)))))
- (setf (%bignum-ref result j) (%bignum-ref bignum-byte i)))))
-
-;;; This assumes at least one digit crossing.
-(defun deposit-unaligned-bignum-bits (bignum-byte pos-digit pos-bits
- end-digit end-bits result)
- (declare (type bignum-index pos-digit end-digit))
- (let* ((bignum-len (%bignum-length bignum-byte))
- (bignum-plusp (%bignum-0-or-plusp bignum-byte bignum-len))
- (low-mask (%make-ones pos-bits))
- (bits-past-pos-bits (- digit-size pos-bits))
- (high-mask (%make-ones bits-past-pos-bits))
- (minus-high-bits (- bits-past-pos-bits)))
- (declare (type bignum-element-type low-mask high-mask)
- (type bignum-index bignum-len))
- (do ((i 0 (1+ i))
- (j pos-digit j+1)
- (j+1 (1+ pos-digit) (1+ j+1)))
- ((or (= j end-digit) (= i bignum-len))
- (cond
- ((= j end-digit)
- (setf (%bignum-ref result j)
- (cond
- ((>= pos-bits end-bits)
- (logand (%bignum-ref result j) (%make-ones end-bits)))
- ((< i bignum-len)
- (logior (%bignum-ref result j)
- (%ashl (logand (%bignum-ref bignum-byte i)
- (%make-ones (- end-bits pos-bits)))
- pos-bits)))
- (bignum-plusp
- (logand (%bignum-ref result j)
- ;; 0's between pos-bits and end-bits positions.
- (logior (%ashl (%make-ones (- digit-size end-bits))
- end-bits)
- low-mask)))
- (t (logior (%bignum-ref result j)
- (%ashl (%make-ones (- end-bits pos-bits))
- pos-bits))))))
- (bignum-plusp)
- (t
- (setf (%bignum-ref result j)
- (%ashl (%make-ones bits-past-pos-bits) pos-bits))
- (do ((j j+1 (1+ j)))
- ((= j end-digit)
- (setf (%bignum-ref result j) (%make-ones end-bits)))
- (declare (type bignum-index j))
- (setf (%bignum-ref result j) all-ones-digit)))))
- (declare (type bignum-index i j j+1))
- (let ((digit (%bignum-ref bignum-byte i)))
- (declare (type bignum-element-type digit))
- (setf (%bignum-ref result j)
- (logior (%bignum-ref result j)
- (%ashl (logand digit high-mask) pos-bits)))
- (setf (%bignum-ref result j+1)
- (logand (ash digit minus-high-bits)
- ;; LOGAND should be unnecessary here with a logical right
- ;; shift or a correct digit-sized one.
- low-mask))))))
-|#
+;;;; There used to be a bunch of code to implement "efficient" versions of LDB
+;;;; and DPB here. But it apparently was never used, so it's been deleted.
+;;;; --njf, 2007-02-04
\f
;;;; TRUNCATE
(defun bignum-truncate (x y)
(declare (type bignum-type x y))
(let (truncate-x truncate-y)
- (labels
+ (labels
;;; Divide X by Y when Y is a single bignum digit. BIGNUM-TRUNCATE
;;; fixes up the quotient and remainder with respect to sign and
;;; normalization.
- ;;;
- ;;; We don't have to worry about shifting Y to make its most
- ;;; significant digit sufficiently large for %FLOOR to return
- ;;; digit-size quantities for the q-digit and r-digit. If Y is
- ;;; a single digit bignum, it is already large enough for
- ;;; %FLOOR. That is, it has some bits on pretty high in the
- ;;; digit.
- ((bignum-truncate-single-digit (x len-x y)
- (declare (type bignum-index len-x))
- (let ((q (%allocate-bignum len-x))
- (r 0)
- (y (%bignum-ref y 0)))
- (declare (type bignum-element-type r y))
- (do ((i (1- len-x) (1- i)))
- ((minusp i))
- (multiple-value-bind (q-digit r-digit)
- (%floor r (%bignum-ref x i) y)
- (declare (type bignum-element-type q-digit r-digit))
- (setf (%bignum-ref q i) q-digit)
- (setf r r-digit)))
- (let ((rem (%allocate-bignum 1)))
- (setf (%bignum-ref rem 0) r)
- (values q rem))))
- ;;; This returns a guess for the next division step. Y1 is the
- ;;; highest y digit, and y2 is the second to highest y
- ;;; digit. The x... variables are the three highest x digits
- ;;; for the next division step.
- ;;;
- ;;; From Knuth, our guess is either all ones or x-i and x-i-1
- ;;; divided by y1, depending on whether x-i and y1 are the
- ;;; same. We test this guess by determining whether guess*y2
- ;;; is greater than the three high digits of x minus guess*y1
- ;;; shifted left one digit:
- ;;; ------------------------------
- ;;; | x-i | x-i-1 | x-i-2 |
- ;;; ------------------------------
- ;;; ------------------------------
- ;;; - | g*y1 high | g*y1 low | 0 |
- ;;; ------------------------------
- ;;; ... < guess*y2 ???
- ;;; If guess*y2 is greater, then we decrement our guess by one
- ;;; and try again. This returns a guess that is either
- ;;; correct or one too large.
- (bignum-truncate-guess (y1 y2 x-i x-i-1 x-i-2)
- (declare (type bignum-element-type y1 y2 x-i x-i-1 x-i-2))
- (let ((guess (if (%digit-compare x-i y1)
- all-ones-digit
- (%floor x-i x-i-1 y1))))
- (declare (type bignum-element-type guess))
- (loop
- (multiple-value-bind (high-guess*y1 low-guess*y1)
- (%multiply guess y1)
- (declare (type bignum-element-type low-guess*y1
- high-guess*y1))
- (multiple-value-bind (high-guess*y2 low-guess*y2)
- (%multiply guess y2)
- (declare (type bignum-element-type high-guess*y2
- low-guess*y2))
- (multiple-value-bind (middle-digit borrow)
- (%subtract-with-borrow x-i-1 low-guess*y1 1)
- (declare (type bignum-element-type middle-digit)
- (fixnum borrow))
- ;; Supplying borrow of 1 means there was no
- ;; borrow, and we know x-i-2 minus 0 requires
- ;; no borrow.
- (let ((high-digit (%subtract-with-borrow x-i
- high-guess*y1
- borrow)))
- (declare (type bignum-element-type high-digit))
- (if (and (%digit-compare high-digit 0)
- (or (%digit-greater high-guess*y2
- middle-digit)
- (and (%digit-compare middle-digit
- high-guess*y2)
- (%digit-greater low-guess*y2
- x-i-2))))
- (setf guess (%subtract-with-borrow guess 1 1))
- (return guess)))))))))
- ;;; Divide TRUNCATE-X by TRUNCATE-Y, returning the quotient
- ;;; and destructively modifying TRUNCATE-X so that it holds
- ;;; the remainder.
- ;;;
- ;;; LEN-X and LEN-Y tell us how much of the buffers we care about.
- ;;;
- ;;; TRUNCATE-X definitely has at least three digits, and it has one
- ;;; more than TRUNCATE-Y. This keeps i, i-1, i-2, and low-x-digit
- ;;; happy. Thanks to SHIFT-AND-STORE-TRUNCATE-BUFFERS.
- (return-quotient-leaving-remainder (len-x len-y)
- (declare (type bignum-index len-x len-y))
- (let* ((len-q (- len-x len-y))
- ;; Add one for extra sign digit in case high bit is on.
- (q (%allocate-bignum (1+ len-q)))
- (k (1- len-q))
- (y1 (%bignum-ref truncate-y (1- len-y)))
- (y2 (%bignum-ref truncate-y (- len-y 2)))
- (i (1- len-x))
- (i-1 (1- i))
- (i-2 (1- i-1))
- (low-x-digit (- i len-y)))
- (declare (type bignum-index len-q k i i-1 i-2 low-x-digit)
- (type bignum-element-type y1 y2))
- (loop
- (setf (%bignum-ref q k)
- (try-bignum-truncate-guess
- ;; This modifies TRUNCATE-X. Must access
- ;; elements each pass.
- (bignum-truncate-guess y1 y2
- (%bignum-ref truncate-x i)
- (%bignum-ref truncate-x i-1)
- (%bignum-ref truncate-x i-2))
- len-y low-x-digit))
- (cond ((zerop k) (return))
- (t (decf k)
- (decf low-x-digit)
- (shiftf i i-1 i-2 (1- i-2)))))
- q))
- ;;; This takes a digit guess, multiplies it by TRUNCATE-Y for a
- ;;; result one greater in length than LEN-Y, and subtracts this result
- ;;; from TRUNCATE-X. LOW-X-DIGIT is the first digit of X to start
- ;;; the subtraction, and we know X is long enough to subtract a LEN-Y
- ;;; plus one length bignum from it. Next we check the result of the
- ;;; subtraction, and if the high digit in X became negative, then our
- ;;; guess was one too big. In this case, return one less than GUESS
- ;;; passed in, and add one value of Y back into X to account for
- ;;; subtracting one too many. Knuth shows that the guess is wrong on
- ;;; the order of 3/b, where b is the base (2 to the digit-size power)
- ;;; -- pretty rarely.
- (try-bignum-truncate-guess (guess len-y low-x-digit)
- (declare (type bignum-index low-x-digit len-y)
- (type bignum-element-type guess))
- (let ((carry-digit 0)
- (borrow 1)
- (i low-x-digit))
- (declare (type bignum-element-type carry-digit)
- (type bignum-index i)
- (fixnum borrow))
- ;; Multiply guess and divisor, subtracting from dividend
- ;; simultaneously.
- (dotimes (j len-y)
- (multiple-value-bind (high-digit low-digit)
- (%multiply-and-add guess
- (%bignum-ref truncate-y j)
- carry-digit)
- (declare (type bignum-element-type high-digit low-digit))
- (setf carry-digit high-digit)
- (multiple-value-bind (x temp-borrow)
- (%subtract-with-borrow (%bignum-ref truncate-x i)
- low-digit
- borrow)
- (declare (type bignum-element-type x)
- (fixnum temp-borrow))
- (setf (%bignum-ref truncate-x i) x)
- (setf borrow temp-borrow)))
- (incf i))
- (setf (%bignum-ref truncate-x i)
- (%subtract-with-borrow (%bignum-ref truncate-x i)
- carry-digit borrow))
- ;; See whether guess is off by one, adding one
- ;; Y back in if necessary.
- (cond ((%digit-0-or-plusp (%bignum-ref truncate-x i))
- guess)
- (t
- ;; If subtraction has negative result, add one
- ;; divisor value back in. The guess was one too
- ;; large in magnitude.
- (let ((i low-x-digit)
- (carry 0))
- (dotimes (j len-y)
- (multiple-value-bind (v k)
- (%add-with-carry (%bignum-ref truncate-y j)
- (%bignum-ref truncate-x i)
- carry)
- (declare (type bignum-element-type v))
- (setf (%bignum-ref truncate-x i) v)
- (setf carry k))
- (incf i))
- (setf (%bignum-ref truncate-x i)
- (%add-with-carry (%bignum-ref truncate-x i)
- 0 carry)))
- (%subtract-with-borrow guess 1 1)))))
- ;;; This returns the amount to shift y to place a one in the
- ;;; second highest bit. Y must be positive. If the last digit
- ;;; of y is zero, then y has a one in the previous digit's
- ;;; sign bit, so we know it will take one less than digit-size
- ;;; to get a one where we want. Otherwise, we count how many
- ;;; right shifts it takes to get zero; subtracting this value
- ;;; from digit-size tells us how many high zeros there are
- ;;; which is one more than the shift amount sought.
- ;;;
- ;;; Note: This is exactly the same as one less than the
- ;;; integer-length of the last digit subtracted from the
- ;;; digit-size.
- ;;;
- ;;; We shift y to make it sufficiently large that doing the
- ;;; 2*digit-size by digit-size %FLOOR calls ensures the quotient and
- ;;; remainder fit in digit-size.
- (shift-y-for-truncate (y)
- (let* ((len (%bignum-length y))
- (last (%bignum-ref y (1- len))))
- (declare (type bignum-index len)
- (type bignum-element-type last))
- (- digit-size (integer-length last) 1)))
- ;;; Stores two bignums into the truncation bignum buffers,
- ;;; shifting them on the way in. This assumes x and y are
- ;;; positive and at least two in length, and it assumes
- ;;; truncate-x and truncate-y are one digit longer than x and
- ;;; y.
- (shift-and-store-truncate-buffers (x len-x y len-y shift)
- (declare (type bignum-index len-x len-y)
- (type (integer 0 (#.digit-size)) shift))
- (cond ((zerop shift)
- (bignum-replace truncate-x x :end1 len-x)
- (bignum-replace truncate-y y :end1 len-y))
- (t
- (bignum-ashift-left-unaligned x 0 shift (1+ len-x)
- truncate-x)
- (bignum-ashift-left-unaligned y 0 shift (1+ len-y)
- truncate-y))))) ;; LABELS
+ ;;;
+ ;;; We don't have to worry about shifting Y to make its most
+ ;;; significant digit sufficiently large for %BIGFLOOR to return
+ ;;; digit-size quantities for the q-digit and r-digit. If Y is
+ ;;; a single digit bignum, it is already large enough for
+ ;;; %BIGFLOOR. That is, it has some bits on pretty high in the
+ ;;; digit.
+ ((bignum-truncate-single-digit (x len-x y)
+ (declare (type bignum-index len-x))
+ (let ((y (%bignum-ref y 0)))
+ (declare (type bignum-element-type y))
+ (if (not (logtest y (1- y)))
+ ;; Y is a power of two.
+ ;; SHIFT-RIGHT-UNALIGNED won't do the right thing
+ ;; with a shift count of 0 or -1, so special case this.
+ (cond ((= y 0)
+ (error 'division-by-zero))
+ ((= y 1)
+ ;; We could probably get away with (VALUES X 0)
+ ;; here, but it's not clear that some of the
+ ;; normalization logic further down would avoid
+ ;; mutilating X. Just go ahead and cons, consing's
+ ;; cheap.
+ (values (copy-bignum x len-x) 0))
+ (t
+ (let ((n-bits (1- (integer-length y))))
+ (values
+ (shift-right-unaligned x 0 n-bits len-x
+ ((= j res-len-1)
+ (setf (%bignum-ref res j)
+ (%ashr (%bignum-ref x i) n-bits))
+ res)
+ res)
+ (logand (%bignum-ref x 0) (1- y))))))
+ (do ((i (1- len-x) (1- i))
+ (q (%allocate-bignum len-x))
+ (r 0))
+ ((minusp i)
+ (let ((rem (%allocate-bignum 1)))
+ (setf (%bignum-ref rem 0) r)
+ (values q rem)))
+ (declare (type bignum-element-type r))
+ (multiple-value-bind (q-digit r-digit)
+ (%bigfloor r (%bignum-ref x i) y)
+ (declare (type bignum-element-type q-digit r-digit))
+ (setf (%bignum-ref q i) q-digit)
+ (setf r r-digit))))))
+ ;;; This returns a guess for the next division step. Y1 is the
+ ;;; highest y digit, and y2 is the second to highest y
+ ;;; digit. The x... variables are the three highest x digits
+ ;;; for the next division step.
+ ;;;
+ ;;; From Knuth, our guess is either all ones or x-i and x-i-1
+ ;;; divided by y1, depending on whether x-i and y1 are the
+ ;;; same. We test this guess by determining whether guess*y2
+ ;;; is greater than the three high digits of x minus guess*y1
+ ;;; shifted left one digit:
+ ;;; ------------------------------
+ ;;; | x-i | x-i-1 | x-i-2 |
+ ;;; ------------------------------
+ ;;; ------------------------------
+ ;;; - | g*y1 high | g*y1 low | 0 |
+ ;;; ------------------------------
+ ;;; ... < guess*y2 ???
+ ;;; If guess*y2 is greater, then we decrement our guess by one
+ ;;; and try again. This returns a guess that is either
+ ;;; correct or one too large.
+ (bignum-truncate-guess (y1 y2 x-i x-i-1 x-i-2)
+ (declare (type bignum-element-type y1 y2 x-i x-i-1 x-i-2))
+ (let ((guess (if (%digit-compare x-i y1)
+ all-ones-digit
+ (%bigfloor x-i x-i-1 y1))))
+ (declare (type bignum-element-type guess))
+ (loop
+ (multiple-value-bind (high-guess*y1 low-guess*y1)
+ (%multiply guess y1)
+ (declare (type bignum-element-type low-guess*y1
+ high-guess*y1))
+ (multiple-value-bind (high-guess*y2 low-guess*y2)
+ (%multiply guess y2)
+ (declare (type bignum-element-type high-guess*y2
+ low-guess*y2))
+ (multiple-value-bind (middle-digit borrow)
+ (%subtract-with-borrow x-i-1 low-guess*y1 1)
+ (declare (type bignum-element-type middle-digit)
+ (fixnum borrow))
+ ;; Supplying borrow of 1 means there was no
+ ;; borrow, and we know x-i-2 minus 0 requires
+ ;; no borrow.
+ (let ((high-digit (%subtract-with-borrow x-i
+ high-guess*y1
+ borrow)))
+ (declare (type bignum-element-type high-digit))
+ (if (and (%digit-compare high-digit 0)
+ (or (%digit-greater high-guess*y2
+ middle-digit)
+ (and (%digit-compare middle-digit
+ high-guess*y2)
+ (%digit-greater low-guess*y2
+ x-i-2))))
+ (setf guess (%subtract-with-borrow guess 1 1))
+ (return guess)))))))))
+ ;;; Divide TRUNCATE-X by TRUNCATE-Y, returning the quotient
+ ;;; and destructively modifying TRUNCATE-X so that it holds
+ ;;; the remainder.
+ ;;;
+ ;;; LEN-X and LEN-Y tell us how much of the buffers we care about.
+ ;;;
+ ;;; TRUNCATE-X definitely has at least three digits, and it has one
+ ;;; more than TRUNCATE-Y. This keeps i, i-1, i-2, and low-x-digit
+ ;;; happy. Thanks to SHIFT-AND-STORE-TRUNCATE-BUFFERS.
+ (return-quotient-leaving-remainder (len-x len-y)
+ (declare (type bignum-index len-x len-y))
+ (let* ((len-q (- len-x len-y))
+ ;; Add one for extra sign digit in case high bit is on.
+ (q (%allocate-bignum (1+ len-q)))
+ (k (1- len-q))
+ (y1 (%bignum-ref truncate-y (1- len-y)))
+ (y2 (%bignum-ref truncate-y (- len-y 2)))
+ (i (1- len-x))
+ (i-1 (1- i))
+ (i-2 (1- i-1))
+ (low-x-digit (- i len-y)))
+ (declare (type bignum-index len-q k i i-1 i-2 low-x-digit)
+ (type bignum-element-type y1 y2))
+ (loop
+ (setf (%bignum-ref q k)
+ (try-bignum-truncate-guess
+ ;; This modifies TRUNCATE-X. Must access
+ ;; elements each pass.
+ (bignum-truncate-guess y1 y2
+ (%bignum-ref truncate-x i)
+ (%bignum-ref truncate-x i-1)
+ (%bignum-ref truncate-x i-2))
+ len-y low-x-digit))
+ (cond ((zerop k) (return))
+ (t (decf k)
+ (decf low-x-digit)
+ (shiftf i i-1 i-2 (1- i-2)))))
+ q))
+ ;;; This takes a digit guess, multiplies it by TRUNCATE-Y for a
+ ;;; result one greater in length than LEN-Y, and subtracts this result
+ ;;; from TRUNCATE-X. LOW-X-DIGIT is the first digit of X to start
+ ;;; the subtraction, and we know X is long enough to subtract a LEN-Y
+ ;;; plus one length bignum from it. Next we check the result of the
+ ;;; subtraction, and if the high digit in X became negative, then our
+ ;;; guess was one too big. In this case, return one less than GUESS
+ ;;; passed in, and add one value of Y back into X to account for
+ ;;; subtracting one too many. Knuth shows that the guess is wrong on
+ ;;; the order of 3/b, where b is the base (2 to the digit-size power)
+ ;;; -- pretty rarely.
+ (try-bignum-truncate-guess (guess len-y low-x-digit)
+ (declare (type bignum-index low-x-digit len-y)
+ (type bignum-element-type guess))
+ (let ((carry-digit 0)
+ (borrow 1)
+ (i low-x-digit))
+ (declare (type bignum-element-type carry-digit)
+ (type bignum-index i)
+ (fixnum borrow))
+ ;; Multiply guess and divisor, subtracting from dividend
+ ;; simultaneously.
+ (dotimes (j len-y)
+ (multiple-value-bind (high-digit low-digit)
+ (%multiply-and-add guess
+ (%bignum-ref truncate-y j)
+ carry-digit)
+ (declare (type bignum-element-type high-digit low-digit))
+ (setf carry-digit high-digit)
+ (multiple-value-bind (x temp-borrow)
+ (%subtract-with-borrow (%bignum-ref truncate-x i)
+ low-digit
+ borrow)
+ (declare (type bignum-element-type x)
+ (fixnum temp-borrow))
+ (setf (%bignum-ref truncate-x i) x)
+ (setf borrow temp-borrow)))
+ (incf i))
+ (setf (%bignum-ref truncate-x i)
+ (%subtract-with-borrow (%bignum-ref truncate-x i)
+ carry-digit borrow))
+ ;; See whether guess is off by one, adding one
+ ;; Y back in if necessary.
+ (cond ((%digit-0-or-plusp (%bignum-ref truncate-x i))
+ guess)
+ (t
+ ;; If subtraction has negative result, add one
+ ;; divisor value back in. The guess was one too
+ ;; large in magnitude.
+ (let ((i low-x-digit)
+ (carry 0))
+ (dotimes (j len-y)
+ (multiple-value-bind (v k)
+ (%add-with-carry (%bignum-ref truncate-y j)
+ (%bignum-ref truncate-x i)
+ carry)
+ (declare (type bignum-element-type v))
+ (setf (%bignum-ref truncate-x i) v)
+ (setf carry k))
+ (incf i))
+ (setf (%bignum-ref truncate-x i)
+ (%add-with-carry (%bignum-ref truncate-x i)
+ 0 carry)))
+ (%subtract-with-borrow guess 1 1)))))
+ ;;; This returns the amount to shift y to place a one in the
+ ;;; second highest bit. Y must be positive. If the last digit
+ ;;; of y is zero, then y has a one in the previous digit's
+ ;;; sign bit, so we know it will take one less than digit-size
+ ;;; to get a one where we want. Otherwise, we count how many
+ ;;; right shifts it takes to get zero; subtracting this value
+ ;;; from digit-size tells us how many high zeros there are
+ ;;; which is one more than the shift amount sought.
+ ;;;
+ ;;; Note: This is exactly the same as one less than the
+ ;;; integer-length of the last digit subtracted from the
+ ;;; digit-size.
+ ;;;
+ ;;; We shift y to make it sufficiently large that doing the
+ ;;; 2*digit-size by digit-size %BIGFLOOR calls ensures the quotient and
+ ;;; remainder fit in digit-size.
+ (shift-y-for-truncate (y)
+ (let* ((len (%bignum-length y))
+ (last (%bignum-ref y (1- len))))
+ (declare (type bignum-index len)
+ (type bignum-element-type last))
+ (- digit-size (integer-length last) 1)))
+ ;;; Stores two bignums into the truncation bignum buffers,
+ ;;; shifting them on the way in. This assumes x and y are
+ ;;; positive and at least two in length, and it assumes
+ ;;; truncate-x and truncate-y are one digit longer than x and
+ ;;; y.
+ (shift-and-store-truncate-buffers (x len-x y len-y shift)
+ (declare (type bignum-index len-x len-y)
+ (type (integer 0 (#.digit-size)) shift))
+ (cond ((zerop shift)
+ (bignum-replace truncate-x x :end1 len-x)
+ (bignum-replace truncate-y y :end1 len-y))
+ (t
+ (bignum-ashift-left-unaligned x 0 shift (1+ len-x)
+ truncate-x)
+ (bignum-ashift-left-unaligned y 0 shift (1+ len-y)
+ truncate-y))))) ;; LABELS
;;; Divide X by Y returning the quotient and remainder. In the
;;; general case, we shift Y to set up for the algorithm, and we
;;; use two buffers to save consing intermediate values. X gets
;;; multiple bind q and r, we first fix up the signs and then
;;; return the normalized results.
(let* ((x-plusp (%bignum-0-or-plusp x (%bignum-length x)))
- (y-plusp (%bignum-0-or-plusp y (%bignum-length y)))
- (x (if x-plusp x (negate-bignum x nil)))
- (y (if y-plusp y (negate-bignum y nil)))
- (len-x (%bignum-length x))
- (len-y (%bignum-length y)))
- (multiple-value-bind (q r)
- (cond ((< len-y 2)
- (bignum-truncate-single-digit x len-x y))
- ((plusp (bignum-compare y x))
- (let ((res (%allocate-bignum len-x)))
- (dotimes (i len-x)
- (setf (%bignum-ref res i) (%bignum-ref x i)))
- (values 0 res)))
- (t
- (let ((len-x+1 (1+ len-x)))
- (setf truncate-x (%allocate-bignum len-x+1))
- (setf truncate-y (%allocate-bignum (1+ len-y)))
- (let ((y-shift (shift-y-for-truncate y)))
- (shift-and-store-truncate-buffers x len-x y
- len-y y-shift)
- (values (return-quotient-leaving-remainder len-x+1
- len-y)
- ;; Now that RETURN-QUOTIENT-LEAVING-REMAINDER
- ;; has executed, we just tidy up the remainder
- ;; (in TRUNCATE-X) and return it.
- (cond
- ((zerop y-shift)
- (let ((res (%allocate-bignum len-y)))
- (declare (type bignum-type res))
- (bignum-replace res truncate-x :end2 len-y)
- (%normalize-bignum res len-y)))
- (t
- (shift-right-unaligned
- truncate-x 0 y-shift len-y
- ((= j res-len-1)
- (setf (%bignum-ref res j)
- (%ashr (%bignum-ref truncate-x i)
- y-shift))
- (%normalize-bignum res res-len))
- res))))))))
- (let ((quotient (cond ((eq x-plusp y-plusp) q)
- ((typep q 'fixnum) (the fixnum (- q)))
- (t (negate-bignum-in-place q))))
- (rem (cond (x-plusp r)
- ((typep r 'fixnum) (the fixnum (- r)))
- (t (negate-bignum-in-place r)))))
- (values (if (typep quotient 'fixnum)
- quotient
- (%normalize-bignum quotient (%bignum-length quotient)))
- (if (typep rem 'fixnum)
- rem
- (%normalize-bignum rem (%bignum-length rem))))))))))
+ (y-plusp (%bignum-0-or-plusp y (%bignum-length y)))
+ (x (if x-plusp x (negate-bignum x nil)))
+ (y (if y-plusp y (negate-bignum y nil)))
+ (len-x (%bignum-length x))
+ (len-y (%bignum-length y)))
+ (multiple-value-bind (q r)
+ (cond ((< len-y 2)
+ (bignum-truncate-single-digit x len-x y))
+ ((plusp (bignum-compare y x))
+ (let ((res (%allocate-bignum len-x)))
+ (dotimes (i len-x)
+ (setf (%bignum-ref res i) (%bignum-ref x i)))
+ (values 0 res)))
+ (t
+ (let ((len-x+1 (1+ len-x)))
+ (setf truncate-x (%allocate-bignum len-x+1))
+ (setf truncate-y (%allocate-bignum (1+ len-y)))
+ (let ((y-shift (shift-y-for-truncate y)))
+ (shift-and-store-truncate-buffers x len-x y
+ len-y y-shift)
+ (values (return-quotient-leaving-remainder len-x+1
+ len-y)
+ ;; Now that RETURN-QUOTIENT-LEAVING-REMAINDER
+ ;; has executed, we just tidy up the remainder
+ ;; (in TRUNCATE-X) and return it.
+ (cond
+ ((zerop y-shift)
+ (let ((res (%allocate-bignum len-y)))
+ (declare (type bignum-type res))
+ (bignum-replace res truncate-x :end2 len-y)
+ (%normalize-bignum res len-y)))
+ (t
+ (shift-right-unaligned
+ truncate-x 0 y-shift len-y
+ ((= j res-len-1)
+ (setf (%bignum-ref res j)
+ (%ashr (%bignum-ref truncate-x i)
+ y-shift))
+ (%normalize-bignum res res-len))
+ res))))))))
+ (let ((quotient (cond ((eq x-plusp y-plusp) q)
+ ((typep q 'fixnum) (the fixnum (- q)))
+ (t (negate-bignum-in-place q))))
+ (rem (cond (x-plusp r)
+ ((typep r 'fixnum) (the fixnum (- r)))
+ (t (negate-bignum-in-place r)))))
+ (values (if (typep quotient 'fixnum)
+ quotient
+ (%normalize-bignum quotient (%bignum-length quotient)))
+ (if (typep rem 'fixnum)
+ rem
+ (%normalize-bignum rem (%bignum-length rem))))))))))
\f
-;;;; %FLOOR primitive for BIGNUM-TRUNCATE
-
-;;; When a machine leaves out a 2*digit-size by digit-size divide
-;;; instruction (that is, two bignum-digits divided by one), we have to
-;;; roll our own (the hard way). Basically, we treat the operation as
-;;; four digit-size/2 digits divided by two digit-size/2 digits. This
-;;; means we have duplicated most of the code above to do this nearly
-;;; general digit-size/2 digit bignum divide, but we've unrolled loops
-;;; and made use of other properties of this specific divide situation.
-
-;;;; %FLOOR for machines with a 32x32 divider.
-
-#!-sb-fluid
-(declaim (inline 32x16-subtract-with-borrow 32x16-add-with-carry
- 32x16-divide 32x16-multiply 32x16-multiply-split))
-
-#!+32x16-divide
-(defconstant 32x16-base-1 (1- (ash 1 (/ sb!vm:n-word-bits 2))))
-
-#!+32x16-divide
-(deftype bignum-half-element-type () `(unsigned-byte ,(/ sb!vm:n-word-bits 2)))
-#!+32x16-divide
-(defconstant half-digit-size (/ digit-size 2))
-
-;;; This is similar to %SUBTRACT-WITH-BORROW. It returns a
-;;; half-digit-size difference and a borrow. Returning a 1 for the
-;;; borrow means there was no borrow, and 0 means there was one.
-#!+32x16-divide
-(defun 32x16-subtract-with-borrow (a b borrow)
- (declare (type bignum-half-element-type a b)
- (type (integer 0 1) borrow))
- (let ((diff (+ (- a b) borrow 32x16-base-1)))
- (declare (type (unsigned-byte #.(1+ half-digit-size)) diff))
- (values (logand diff (1- (ash 1 half-digit-size)))
- (ash diff (- half-digit-size)))))
-
-;;; This adds a and b, half-digit-size quantities, with the carry k. It
-;;; returns a half-digit-size sum and a second value, 0 or 1, indicating
-;;; whether there was a carry.
-#!+32x16-divide
-(defun 32x16-add-with-carry (a b k)
- (declare (type bignum-half-element-type a b)
- (type (integer 0 1) k))
- (let ((res (the fixnum (+ a b k))))
- (declare (type (unsigned-byte #.(1+ half-digit-size)) res))
- (if (zerop (the fixnum (logand (ash 1 half-digit-size) res)))
- (values res 0)
- (values (the bignum-half-element-type (logand (1- (ash 1 half-digit-size)) res))
- 1))))
-
-;;; This is probably a digit-size by digit-size divide instruction.
-#!+32x16-divide
-(defun 32x16-divide (a b c)
- (declare (type bignum-half-element-type a b c))
- (floor (the bignum-element-type
- (logior (the bignum-element-type (ash a 16))
- b))
- c))
-
-;;; This basically exists since we know the answer won't overflow
-;;; bignum-element-type. It's probably just a basic multiply instruction, but
-;;; it can't cons an intermediate bignum. The result goes in a non-descriptor
-;;; register.
-#!+32x16-divide
-(defun 32x16-multiply (a b)
- (declare (type bignum-half-element-type a b))
- (the bignum-element-type (* a b)))
-
-;;; This multiplies a and b, half-digit-size quantities, and returns the
-;;; result as two half-digit-size quantities, high and low.
-#!+32x16-divide
-(defun 32x16-multiply-split (a b)
- (let ((res (32x16-multiply a b)))
- (declare (the bignum-element-type res))
- (values (the bignum-half-element-type (logand (1- (ash 1 half-digit-size)) (ash res (- half-digit-size))))
- (the bignum-half-element-type (logand (1- (ash 1 half-digit-size)) res)))))
-
-;;; The %FLOOR below uses this buffer the same way BIGNUM-TRUNCATE uses
-;;; *truncate-x*. There's no y buffer since we pass around the two
-;;; half-digit-size digits and use them slightly differently than the
-;;; general truncation algorithm above.
-#!+32x16-divide
-(defvar *32x16-truncate-x* (make-array 4 :element-type 'bignum-half-element-type
- :initial-element 0))
-
-;;; This does the same thing as the %FLOOR above, but it does it at Lisp level
-;;; when there is no 64x32-bit divide instruction on the machine.
-;;;
-;;; It implements the higher level tactics of BIGNUM-TRUNCATE, but it
-;;; makes use of special situation provided, four half-digit-size digits
-;;; divided by two half-digit-size digits.
-#!+32x16-divide
-(defun %floor (a b c)
- (declare (type bignum-element-type a b c))
- ;; Setup *32x16-truncate-x* buffer from a and b.
- (setf (aref *32x16-truncate-x* 0)
- (the bignum-half-element-type (logand (1- (ash 1 half-digit-size)) b)))
- (setf (aref *32x16-truncate-x* 1)
- (the bignum-half-element-type
- (logand (1- (ash 1 half-digit-size))
- (the bignum-half-element-type (ash b (- half-digit-size))))))
- (setf (aref *32x16-truncate-x* 2)
- (the bignum-half-element-type (logand (1- (ash 1 half-digit-size)) a)))
- (setf (aref *32x16-truncate-x* 3)
- (the bignum-half-element-type
- (logand (1- (ash 1 half-digit-size))
- (the bignum-half-element-type (ash a (- half-digit-size))))))
- ;; From DO-TRUNCATE, but unroll the loop.
- (let* ((y1 (logand (1- (ash 1 half-digit-size)) (ash c (- half-digit-size))))
- (y2 (logand (1- (ash 1 half-digit-size)) c))
- (q (the bignum-element-type
- (ash (32x16-try-bignum-truncate-guess
- (32x16-truncate-guess y1 y2
- (aref *32x16-truncate-x* 3)
- (aref *32x16-truncate-x* 2)
- (aref *32x16-truncate-x* 1))
- y1 y2 1)
- 16))))
- (declare (type bignum-element-type q)
- (type bignum-half-element-type y1 y2))
- (values (the bignum-element-type
- (logior q
- (the bignum-half-element-type
- (32x16-try-bignum-truncate-guess
- (32x16-truncate-guess
- y1 y2
- (aref *32x16-truncate-x* 2)
- (aref *32x16-truncate-x* 1)
- (aref *32x16-truncate-x* 0))
- y1 y2 0))))
- (the bignum-element-type
- (logior (the bignum-element-type
- (ash (aref *32x16-truncate-x* 1) 16))
- (the bignum-half-element-type
- (aref *32x16-truncate-x* 0)))))))
-
-;;; This is similar to TRY-BIGNUM-TRUNCATE-GUESS, but this unrolls the two
-;;; loops. This also substitutes for %DIGIT-0-OR-PLUSP the equivalent
-;;; expression without any embellishment or pretense of abstraction. The first
-;;; loop is unrolled, but we've put the body of the loop into the function
-;;; 32X16-TRY-GUESS-ONE-RESULT-DIGIT.
-#!+32x16-divide
-(defun 32x16-try-bignum-truncate-guess (guess y-high y-low low-x-digit)
- (declare (type bignum-index low-x-digit)
- (type bignum-half-element-type guess y-high y-low))
- (let ((high-x-digit (+ 2 low-x-digit)))
- ;; Multiply guess and divisor, subtracting from dividend simultaneously.
- (multiple-value-bind (guess*y-hold carry borrow)
- (32x16-try-guess-one-result-digit guess y-low 0 0 1 low-x-digit)
- (declare (type bignum-half-element-type guess*y-hold)
- (fixnum carry borrow))
- (multiple-value-bind (guess*y-hold carry borrow)
- (32x16-try-guess-one-result-digit guess y-high guess*y-hold
- carry borrow (1+ low-x-digit))
- (declare (type bignum-half-element-type guess*y-hold)
- (fixnum borrow)
- (ignore carry))
- (setf (aref *32x16-truncate-x* high-x-digit)
- (32x16-subtract-with-borrow (aref *32x16-truncate-x* high-x-digit)
- guess*y-hold borrow))))
- ;; See whether guess is off by one, adding one Y back in if necessary.
- (cond ((zerop (logand (ash 1 (1- half-digit-size))
- (aref *32x16-truncate-x* high-x-digit)))
- ;; The subtraction result is zero or positive.
- guess)
- (t
- ;; If subtraction has negative result, add one divisor value back
- ;; in. The guess was one too large in magnitude.
- (multiple-value-bind (v carry)
- (32x16-add-with-carry y-low
- (aref *32x16-truncate-x* low-x-digit)
- 0)
- (declare (type bignum-half-element-type v))
- (setf (aref *32x16-truncate-x* low-x-digit) v)
- (multiple-value-bind (v carry)
- (32x16-add-with-carry y-high
- (aref *32x16-truncate-x*
- (1+ low-x-digit))
- carry)
- (setf (aref *32x16-truncate-x* (1+ low-x-digit)) v)
- (setf (aref *32x16-truncate-x* high-x-digit)
- (32x16-add-with-carry (aref *32x16-truncate-x* high-x-digit)
- carry 0))))
- (if (zerop (logand (ash 1 (1- half-digit-size)) guess))
- (1- guess)
- (1+ guess))))))
-
-;;; This is similar to the body of the loop in TRY-BIGNUM-TRUNCATE-GUESS that
-;;; multiplies the guess by y and subtracts the result from x simultaneously.
-;;; This returns the digit remembered as part of the multiplication, the carry
-;;; from additions done on behalf of the multiplication, and the borrow from
-;;; doing the subtraction.
-#!+32x16-divide
-(defun 32x16-try-guess-one-result-digit (guess y-digit guess*y-hold
- carry borrow x-index)
- (multiple-value-bind (high-digit low-digit)
- (32x16-multiply-split guess y-digit)
- (declare (type bignum-half-element-type high-digit low-digit))
- (multiple-value-bind (low-digit temp-carry)
- (32x16-add-with-carry low-digit guess*y-hold carry)
- (declare (type bignum-half-element-type low-digit))
- (multiple-value-bind (high-digit temp-carry)
- (32x16-add-with-carry high-digit temp-carry 0)
- (declare (type bignum-half-element-type high-digit))
- (multiple-value-bind (x temp-borrow)
- (32x16-subtract-with-borrow (aref *32x16-truncate-x* x-index)
- low-digit borrow)
- (declare (type bignum-half-element-type x))
- (setf (aref *32x16-truncate-x* x-index) x)
- (values high-digit temp-carry temp-borrow))))))
-
-;;; This is similar to BIGNUM-TRUNCATE-GUESS, but instead of computing
-;;; the guess exactly as described in the its comments (digit by digit),
-;;; this massages the digit-size/2 quantities into digit-size quantities
-;;; and performs the
-#!+32x16-divide
-(defun 32x16-truncate-guess (y1 y2 x-i x-i-1 x-i-2)
- (declare (type bignum-half-element-type y1 y2 x-i x-i-1 x-i-2))
- (let ((guess (if (= x-i y1)
- (1- (ash 1 half-digit-size))
- (32x16-divide x-i x-i-1 y1))))
- (declare (type bignum-half-element-type guess))
- (loop
- (let* ((guess*y1 (the bignum-element-type
- (ash (logand (1- (ash 1 half-digit-size))
- (the bignum-element-type
- (32x16-multiply guess y1)))
- 16)))
- (x-y (%subtract-with-borrow
- (the bignum-element-type
- (logior (the bignum-element-type
- (ash x-i-1 16))
- x-i-2))
- guess*y1
- 1))
- (guess*y2 (the bignum-element-type (%multiply guess y2))))
- (declare (type bignum-element-type guess*y1 x-y guess*y2))
- (if (%digit-greater guess*y2 x-y)
- (decf guess)
- (return guess))))))
+;;;; There used to be a pile of code for implementing division for bignum digits
+;;;; for machines that don't have a 2*digit-size by digit-size divide instruction.
+;;;; This happens to be most machines, but all the SBCL ports seem to be content
+;;;; to implement SB-BIGNUM:%BIGFLOOR as a VOP rather than using the code here.
+;;;; So it's been deleted. --njf, 2007-02-04
\f
;;;; general utilities
#!-sb-fluid (declaim (sb!ext:maybe-inline %normalize-bignum-buffer))
(defun %normalize-bignum-buffer (result len)
(declare (type bignum-type result)
- (type bignum-index len))
+ (type bignum-index len))
(unless (= len 1)
(do ((next-digit (%bignum-ref result (- len 2))
- (%bignum-ref result (- len 2)))
- (sign-digit (%bignum-ref result (1- len)) next-digit))
- ((not (zerop (logxor sign-digit (%ashr next-digit (1- digit-size))))))
- (decf len)
- (setf (%bignum-ref result len) 0)
- (when (= len 1)
- (return))))
+ (%bignum-ref result (- len 2)))
+ (sign-digit (%bignum-ref result (1- len)) next-digit))
+ ((not (zerop (logxor sign-digit (%ashr next-digit (1- digit-size))))))
+ (decf len)
+ (setf (%bignum-ref result len) 0)
+ (when (= len 1)
+ (return))))
len)
;;; This drops the last digit if it is unnecessary sign information. It repeats
;;; we do have a fixnum, shift it over for the two low-tag bits.
(defun %normalize-bignum (result len)
(declare (type bignum-type result)
- (type bignum-index len)
- (inline %normalize-bignum-buffer))
+ (type bignum-index len)
+ (inline %normalize-bignum-buffer))
(let ((newlen (%normalize-bignum-buffer result len)))
(declare (type bignum-index newlen))
(unless (= newlen len)
(%bignum-set-length result newlen))
(if (= newlen 1)
- (let ((digit (%bignum-ref result 0)))
- (if (= (%ashr digit sb!vm:n-positive-fixnum-bits)
+ (let ((digit (%bignum-ref result 0)))
+ (if (= (%ashr digit sb!vm:n-positive-fixnum-bits)
(%ashr digit (1- digit-size)))
- (%fixnum-digit-with-correct-sign digit)
- result))
- result)))
+ (%fixnum-digit-with-correct-sign digit)
+ result))
+ result)))
;;; This drops the last digit if it is unnecessary sign information. It
;;; repeats this as needed, possibly ending with a fixnum magnitude but never
;;; returning a fixnum.
(defun %mostly-normalize-bignum (result len)
(declare (type bignum-type result)
- (type bignum-index len)
- (inline %normalize-bignum-buffer))
+ (type bignum-index len)
+ (inline %normalize-bignum-buffer))
(let ((newlen (%normalize-bignum-buffer result len)))
(declare (type bignum-index newlen))
(unless (= newlen len)
(dotimes (i (%bignum-length x))
(declare (type index i))
(let ((xi (%bignum-ref x i)))
- (mixf result
- (logand most-positive-fixnum
- xi
- (ash xi -7)))))
+ (mixf result
+ (logand most-positive-fixnum
+ (logxor xi
+ (ash xi -7))))))
result))
projects / sbcl.git / blobdiff