(deftransform hairy-data-vector-ref ((string index) (simple-string t))
(let ((ctype (lvar-type string)))
(if (array-type-p ctype)
- ;; the other transform will kick in, so that's OK
- (give-up-ir1-transform)
- `(etypecase string
- ((simple-array character (*)) (data-vector-ref string index))
+ ;; the other transform will kick in, so that's OK
+ (give-up-ir1-transform)
+ `(etypecase string
+ ((simple-array character (*)) (data-vector-ref string index))
#!+sb-unicode
- ((simple-array base-char (*)) (data-vector-ref string index))
- ((simple-array nil (*)) (data-vector-ref string index))))))
+ ((simple-array base-char (*)) (data-vector-ref string index))
+ ((simple-array nil (*)) (data-vector-ref string index))))))
(deftransform hairy-data-vector-ref ((array index) (array t) *)
"avoid runtime dispatch on array element type"
(let ((element-ctype (extract-upgraded-element-type array))
- (declared-element-ctype (extract-declared-element-type array)))
+ (declared-element-ctype (extract-declared-element-type array)))
(declare (type ctype element-ctype))
(when (eq *wild-type* element-ctype)
(give-up-ir1-transform
;; to hand-expand it ourselves.)
(let ((element-type-specifier (type-specifier element-ctype)))
`(multiple-value-bind (array index)
- (%data-vector-and-index array index)
- (declare (type (simple-array ,element-type-specifier 1) array))
- ,(let ((bare-form '(data-vector-ref array index)))
- (if (type= element-ctype declared-element-ctype)
- bare-form
- `(the ,(type-specifier declared-element-ctype)
- ,bare-form)))))))
+ (%data-vector-and-index array index)
+ (declare (type (simple-array ,element-type-specifier 1) array))
+ ,(let ((bare-form '(data-vector-ref array index)))
+ (if (type= element-ctype declared-element-ctype)
+ bare-form
+ `(the ,(type-specifier declared-element-ctype)
+ ,bare-form)))))))
(deftransform data-vector-ref ((array index)
(simple-array t))
index)))))
(deftransform hairy-data-vector-set ((string index new-value)
- (simple-string t t))
+ (simple-string t t))
(let ((ctype (lvar-type string)))
(if (array-type-p ctype)
- ;; the other transform will kick in, so that's OK
- (give-up-ir1-transform)
- `(etypecase string
- ((simple-array character (*))
- (data-vector-set string index new-value))
+ ;; the other transform will kick in, so that's OK
+ (give-up-ir1-transform)
+ `(etypecase string
+ ((simple-array character (*))
+ (data-vector-set string index new-value))
#!+sb-unicode
- ((simple-array base-char (*))
- (data-vector-set string index new-value))
- ((simple-array nil (*))
- (data-vector-set string index new-value))))))
+ ((simple-array base-char (*))
+ (data-vector-set string index new-value))
+ ((simple-array nil (*))
+ (data-vector-set string index new-value))))))
(deftransform hairy-data-vector-set ((array index new-value)
- (array t t)
- *)
+ (array t t)
+ *)
"avoid runtime dispatch on array element type"
(let ((element-ctype (extract-upgraded-element-type array))
- (declared-element-ctype (extract-declared-element-type array)))
+ (declared-element-ctype (extract-declared-element-type array)))
(declare (type ctype element-ctype))
(when (eq *wild-type* element-ctype)
(give-up-ir1-transform
"Upgraded element type of array is not known at compile time."))
(let ((element-type-specifier (type-specifier element-ctype)))
`(multiple-value-bind (array index)
- (%data-vector-and-index array index)
- (declare (type (simple-array ,element-type-specifier 1) array)
- (type ,element-type-specifier new-value))
- ,(if (type= element-ctype declared-element-ctype)
- '(data-vector-set array index new-value)
- `(truly-the ,(type-specifier declared-element-ctype)
- (data-vector-set array index
- (the ,(type-specifier declared-element-ctype)
- new-value))))))))
+ (%data-vector-and-index array index)
+ (declare (type (simple-array ,element-type-specifier 1) array)
+ (type ,element-type-specifier new-value))
+ ,(if (type= element-ctype declared-element-ctype)
+ '(data-vector-set array index new-value)
+ `(truly-the ,(type-specifier declared-element-ctype)
+ (data-vector-set array index
+ (the ,(type-specifier declared-element-ctype)
+ new-value))))))))
(deftransform data-vector-set ((array index new-value)
(simple-array t t))
index)))))
(deftransform %data-vector-and-index ((%array %index)
- (simple-array t)
- *)
+ (simple-array t)
+ *)
;; KLUDGE: why the percent signs? Well, ARRAY and INDEX are
;; respectively exported from the CL and SB!INT packages, which
;; means that they're visible to all sorts of things. If the
(macrolet
((frob (type bits)
(let ((elements-per-word (truncate sb!vm:n-word-bits bits)))
- `(progn
- (deftransform data-vector-ref ((vector index)
- (,type *))
- `(multiple-value-bind (word bit)
- (floor index ,',elements-per-word)
- (ldb ,(ecase sb!vm:target-byte-order
- (:little-endian '(byte ,bits (* bit ,bits)))
- (:big-endian '(byte ,bits (- sb!vm:n-word-bits
- (* (1+ bit) ,bits)))))
- (%raw-bits vector (+ word sb!vm:vector-data-offset)))))
- (deftransform data-vector-set ((vector index new-value)
- (,type * *))
- `(multiple-value-bind (word bit)
- (floor index ,',elements-per-word)
- (setf (ldb ,(ecase sb!vm:target-byte-order
- (:little-endian '(byte ,bits (* bit ,bits)))
- (:big-endian
- '(byte ,bits (- sb!vm:n-word-bits
- (* (1+ bit) ,bits)))))
- (%raw-bits vector (+ word sb!vm:vector-data-offset)))
- new-value)))))))
+ `(progn
+ (deftransform data-vector-ref ((vector index)
+ (,type *))
+ `(multiple-value-bind (word bit)
+ (floor index ,',elements-per-word)
+ (ldb ,(ecase sb!vm:target-byte-order
+ (:little-endian '(byte ,bits (* bit ,bits)))
+ (:big-endian '(byte ,bits (- sb!vm:n-word-bits
+ (* (1+ bit) ,bits)))))
+ (%raw-bits vector (+ word sb!vm:vector-data-offset)))))
+ (deftransform data-vector-set ((vector index new-value)
+ (,type * *))
+ `(multiple-value-bind (word bit)
+ (floor index ,',elements-per-word)
+ (setf (ldb ,(ecase sb!vm:target-byte-order
+ (:little-endian '(byte ,bits (* bit ,bits)))
+ (:big-endian
+ '(byte ,bits (- sb!vm:n-word-bits
+ (* (1+ bit) ,bits)))))
+ (%raw-bits vector (+ word sb!vm:vector-data-offset)))
+ new-value)))))))
(frob simple-bit-vector 1)
(frob (simple-array (unsigned-byte 2) (*)) 2)
(frob (simple-array (unsigned-byte 4) (*)) 4))
(macrolet ((def (bitfun wordfun)
`(deftransform ,bitfun ((bit-array-1 bit-array-2 result-bit-array)
(simple-bit-vector
- simple-bit-vector
- simple-bit-vector)
- *
+ simple-bit-vector
+ simple-bit-vector)
+ *
:node node :policy (>= speed space))
`(progn
,@(unless (policy node (zerop safety))
'((unless (= (length bit-array-1)
- (length bit-array-2)
+ (length bit-array-2)
(length result-bit-array))
(error "Argument and/or result bit arrays are not the same length:~
~% ~S~% ~S ~% ~S"
bit-array-1
- bit-array-2
- result-bit-array))))
- (let ((length (length result-bit-array)))
- (if (= length 0)
- ;; We avoid doing anything to 0-length
- ;; bit-vectors, or rather, the memory that
- ;; follows them. Other divisible-by-32 cases
- ;; are handled by the (1- length), below.
- ;; CSR, 2002-04-24
- result-bit-array
- (do ((index sb!vm:vector-data-offset (1+ index))
- (end-1 (+ sb!vm:vector-data-offset
- ;; bit-vectors of length 1-32
- ;; need precisely one (SETF
- ;; %RAW-BITS), done here in the
- ;; epilogue. - CSR, 2002-04-24
- (truncate (truly-the index (1- length))
- sb!vm:n-word-bits))))
- ((= index end-1)
- (setf (%raw-bits result-bit-array index)
- (,',wordfun (%raw-bits bit-array-1 index)
- (%raw-bits bit-array-2 index)))
- result-bit-array)
- (declare (optimize (speed 3) (safety 0))
- (type index index end-1))
- (setf (%raw-bits result-bit-array index)
- (,',wordfun (%raw-bits bit-array-1 index)
- (%raw-bits bit-array-2 index))))))))))
+ bit-array-2
+ result-bit-array))))
+ (let ((length (length result-bit-array)))
+ (if (= length 0)
+ ;; We avoid doing anything to 0-length
+ ;; bit-vectors, or rather, the memory that
+ ;; follows them. Other divisible-by-32 cases
+ ;; are handled by the (1- length), below.
+ ;; CSR, 2002-04-24
+ result-bit-array
+ (do ((index sb!vm:vector-data-offset (1+ index))
+ (end-1 (+ sb!vm:vector-data-offset
+ ;; bit-vectors of length 1-32
+ ;; need precisely one (SETF
+ ;; %RAW-BITS), done here in the
+ ;; epilogue. - CSR, 2002-04-24
+ (truncate (truly-the index (1- length))
+ sb!vm:n-word-bits))))
+ ((= index end-1)
+ (setf (%raw-bits result-bit-array index)
+ (,',wordfun (%raw-bits bit-array-1 index)
+ (%raw-bits bit-array-2 index)))
+ result-bit-array)
+ (declare (optimize (speed 3) (safety 0))
+ (type index index end-1))
+ (setf (%raw-bits result-bit-array index)
+ (,',wordfun (%raw-bits bit-array-1 index)
+ (%raw-bits bit-array-2 index))))))))))
(def bit-and word-logical-and)
(def bit-ior word-logical-or)
(def bit-xor word-logical-xor)
(def bit-orc2 word-logical-orc2))
(deftransform bit-not
- ((bit-array result-bit-array)
- (simple-bit-vector simple-bit-vector) *
- :node node :policy (>= speed space))
+ ((bit-array result-bit-array)
+ (simple-bit-vector simple-bit-vector) *
+ :node node :policy (>= speed space))
`(progn
,@(unless (policy node (zerop safety))
- '((unless (= (length bit-array)
- (length result-bit-array))
- (error "Argument and result bit arrays are not the same length:~
+ '((unless (= (length bit-array)
+ (length result-bit-array))
+ (error "Argument and result bit arrays are not the same length:~
~% ~S~% ~S"
- bit-array result-bit-array))))
+ bit-array result-bit-array))))
(let ((length (length result-bit-array)))
(if (= length 0)
- ;; We avoid doing anything to 0-length bit-vectors, or rather,
- ;; the memory that follows them. Other divisible-by
- ;; n-word-bits cases are handled by the (1- length), below.
- ;; CSR, 2002-04-24
- result-bit-array
- (do ((index sb!vm:vector-data-offset (1+ index))
- (end-1 (+ sb!vm:vector-data-offset
- ;; bit-vectors of length 1 to n-word-bits need
- ;; precisely one (SETF %RAW-BITS), done here in
- ;; the epilogue. - CSR, 2002-04-24
- (truncate (truly-the index (1- length))
- sb!vm:n-word-bits))))
- ((= index end-1)
- (setf (%raw-bits result-bit-array index)
- (word-logical-not (%raw-bits bit-array index)))
- result-bit-array)
- (declare (optimize (speed 3) (safety 0))
- (type index index end-1))
- (setf (%raw-bits result-bit-array index)
- (word-logical-not (%raw-bits bit-array index))))))))
+ ;; We avoid doing anything to 0-length bit-vectors, or rather,
+ ;; the memory that follows them. Other divisible-by
+ ;; n-word-bits cases are handled by the (1- length), below.
+ ;; CSR, 2002-04-24
+ result-bit-array
+ (do ((index sb!vm:vector-data-offset (1+ index))
+ (end-1 (+ sb!vm:vector-data-offset
+ ;; bit-vectors of length 1 to n-word-bits need
+ ;; precisely one (SETF %RAW-BITS), done here in
+ ;; the epilogue. - CSR, 2002-04-24
+ (truncate (truly-the index (1- length))
+ sb!vm:n-word-bits))))
+ ((= index end-1)
+ (setf (%raw-bits result-bit-array index)
+ (word-logical-not (%raw-bits bit-array index)))
+ result-bit-array)
+ (declare (optimize (speed 3) (safety 0))
+ (type index index end-1))
+ (setf (%raw-bits result-bit-array index)
+ (word-logical-not (%raw-bits bit-array index))))))))
(deftransform bit-vector-= ((x y) (simple-bit-vector simple-bit-vector))
`(and (= (length x) (length y))
(let ((length (length x)))
- (or (= length 0)
- (do* ((i sb!vm:vector-data-offset (+ i 1))
- (end-1 (+ sb!vm:vector-data-offset
- (floor (1- length) sb!vm:n-word-bits))))
- ((= i end-1)
- (let* ((extra (1+ (mod (1- length) sb!vm:n-word-bits)))
- (mask (1- (ash 1 extra)))
- (numx
- (logand
- (ash mask
- ,(ecase sb!c:*backend-byte-order*
- (:little-endian 0)
- (:big-endian
- '(- sb!vm:n-word-bits extra))))
- (%raw-bits x i)))
- (numy
- (logand
- (ash mask
- ,(ecase sb!c:*backend-byte-order*
- (:little-endian 0)
- (:big-endian
- '(- sb!vm:n-word-bits extra))))
- (%raw-bits y i))))
- (declare (type (integer 1 #.sb!vm:n-word-bits) extra)
- (type sb!vm:word mask numx numy))
- (= numx numy)))
- (declare (type index i end-1))
- (let ((numx (%raw-bits x i))
- (numy (%raw-bits y i)))
- (declare (type sb!vm:word numx numy))
- (unless (= numx numy)
- (return nil))))))))
+ (or (= length 0)
+ (do* ((i sb!vm:vector-data-offset (+ i 1))
+ (end-1 (+ sb!vm:vector-data-offset
+ (floor (1- length) sb!vm:n-word-bits))))
+ ((= i end-1)
+ (let* ((extra (1+ (mod (1- length) sb!vm:n-word-bits)))
+ (mask (ash #.(1- (ash 1 sb!vm:n-word-bits))
+ (- extra sb!vm:n-word-bits)))
+ (numx
+ (logand
+ (ash mask
+ ,(ecase sb!c:*backend-byte-order*
+ (:little-endian 0)
+ (:big-endian
+ '(- sb!vm:n-word-bits extra))))
+ (%raw-bits x i)))
+ (numy
+ (logand
+ (ash mask
+ ,(ecase sb!c:*backend-byte-order*
+ (:little-endian 0)
+ (:big-endian
+ '(- sb!vm:n-word-bits extra))))
+ (%raw-bits y i))))
+ (declare (type (integer 1 #.sb!vm:n-word-bits) extra)
+ (type sb!vm:word mask numx numy))
+ (= numx numy)))
+ (declare (type index i end-1))
+ (let ((numx (%raw-bits x i))
+ (numy (%raw-bits y i)))
+ (declare (type sb!vm:word numx numy))
+ (unless (= numx numy)
+ (return nil))))))))
(deftransform count ((item sequence) (bit simple-bit-vector) *
:policy (>= speed space))
sb!vm:n-word-bits))))
((= index end-1)
(let* ((extra (1+ (mod (1- length) sb!vm:n-word-bits)))
- (mask (1- (ash 1 extra)))
- (bits (logand (ash mask
- ,(ecase sb!c:*backend-byte-order*
- (:little-endian 0)
- (:big-endian
- '(- sb!vm:n-word-bits extra))))
- (%raw-bits sequence index))))
+ (mask (ash #.(1- (ash 1 sb!vm:n-word-bits))
+ (- extra sb!vm:n-word-bits)))
+ (bits (logand (ash mask
+ ,(ecase sb!c:*backend-byte-order*
+ (:little-endian 0)
+ (:big-endian
+ '(- sb!vm:n-word-bits extra))))
+ (%raw-bits sequence index))))
(declare (type (integer 1 #.sb!vm:n-word-bits) extra))
(declare (type sb!vm:word mask bits))
;; could consider LOGNOT for the zero case instead of
(- extra (logcount bits))
(logcount bits))))))
(declare (type index index count end-1)
- (optimize (speed 3) (safety 0)))
+ (optimize (speed 3) (safety 0)))
(incf count ,(if (constant-lvar-p item)
(if (zerop (lvar-value item))
'(- sb!vm:n-word-bits (logcount (%raw-bits sequence index)))
(logcount (%raw-bits sequence index)))))))))
(deftransform fill ((sequence item) (simple-bit-vector bit) *
- :policy (>= speed space))
+ :policy (>= speed space))
(let ((value (if (constant-lvar-p item)
- (if (= (lvar-value item) 0)
- 0
- #.(1- (ash 1 sb!vm:n-word-bits)))
- `(if (= item 0) 0 #.(1- (ash 1 sb!vm:n-word-bits))))))
+ (if (= (lvar-value item) 0)
+ 0
+ #.(1- (ash 1 sb!vm:n-word-bits)))
+ `(if (= item 0) 0 #.(1- (ash 1 sb!vm:n-word-bits))))))
`(let ((length (length sequence))
- (value ,value))
+ (value ,value))
(if (= length 0)
- sequence
- (do ((index sb!vm:vector-data-offset (1+ index))
- (end-1 (+ sb!vm:vector-data-offset
- ;; bit-vectors of length 1 to n-word-bits need
- ;; precisely one (SETF %RAW-BITS), done here
+ sequence
+ (do ((index sb!vm:vector-data-offset (1+ index))
+ (end-1 (+ sb!vm:vector-data-offset
+ ;; bit-vectors of length 1 to n-word-bits need
+ ;; precisely one (SETF %RAW-BITS), done here
;; in the epilogue. - CSR, 2002-04-24
- (truncate (truly-the index (1- length))
- sb!vm:n-word-bits))))
- ((= index end-1)
- (setf (%raw-bits sequence index) value)
- sequence)
- (declare (optimize (speed 3) (safety 0))
- (type index index end-1))
- (setf (%raw-bits sequence index) value))))))
+ (truncate (truly-the index (1- length))
+ sb!vm:n-word-bits))))
+ ((= index end-1)
+ (setf (%raw-bits sequence index) value)
+ sequence)
+ (declare (optimize (speed 3) (safety 0))
+ (type index index end-1))
+ (setf (%raw-bits sequence index) value))))))
(deftransform fill ((sequence item) (simple-base-string base-char) *
- :policy (>= speed space))
+ :policy (>= speed space))
(let ((value (if (constant-lvar-p item)
- (let* ((char (lvar-value item))
- (code (sb!xc:char-code char))
+ (let* ((char (lvar-value item))
+ (code (sb!xc:char-code char))
(accum 0))
(dotimes (i sb!vm:n-word-bytes accum)
(setf accum (logior accum (ash code (* 8 i))))))
- `(let ((code (sb!xc:char-code item)))
+ `(let ((code (sb!xc:char-code item)))
(logior ,@(loop for i from 0 below sb!vm:n-word-bytes
collect `(ash code ,(* 8 i))))))))
`(let ((length (length sequence))
- (value ,value))
+ (value ,value))
(multiple-value-bind (times rem)
- (truncate length sb!vm:n-word-bytes)
- (do ((index sb!vm:vector-data-offset (1+ index))
- (end (+ times sb!vm:vector-data-offset)))
- ((= index end)
- (let ((place (* times sb!vm:n-word-bytes)))
- (declare (fixnum place))
- (dotimes (j rem sequence)
- (declare (index j))
- (setf (schar sequence (the index (+ place j))) item))))
- (declare (optimize (speed 3) (safety 0))
- (type index index))
- (setf (%raw-bits sequence index) value))))))
+ (truncate length sb!vm:n-word-bytes)
+ (do ((index sb!vm:vector-data-offset (1+ index))
+ (end (+ times sb!vm:vector-data-offset)))
+ ((= index end)
+ (let ((place (* times sb!vm:n-word-bytes)))
+ (declare (fixnum place))
+ (dotimes (j rem sequence)
+ (declare (index j))
+ (setf (schar sequence (the index (+ place j))) item))))
+ (declare (optimize (speed 3) (safety 0))
+ (type index index))
+ (setf (%raw-bits sequence index) value))))))
\f
;;;; %BYTE-BLT
;;; SB!KERNEL and SB!SYS (e.g. i/o code). It's not clear that it's the
;;; ideal interface, though, and it probably deserves some thought.
(deftransform %byte-blt ((src src-start dst dst-start dst-end)
- ((or (simple-unboxed-array (*)) system-area-pointer)
- index
- (or (simple-unboxed-array (*)) system-area-pointer)
- index
- index))
+ ((or (simple-unboxed-array (*)) system-area-pointer)
+ index
+ (or (simple-unboxed-array (*)) system-area-pointer)
+ index
+ index))
;; FIXME: CMU CL had a hairier implementation of this (back when it
;; was still called (%PRIMITIVE BYTE-BLT). It had the small problem
;; that it didn't work for large (>16M) values of SRC-START or
;; acceptable for SQRT and COS, it's acceptable here, but this
;; should probably be checked. -- WHN
'(flet ((sapify (thing)
- (etypecase thing
- (system-area-pointer thing)
- ;; FIXME: The code here rather relies on the simple
- ;; unboxed array here having byte-sized entries. That
- ;; should be asserted explicitly, I just haven't found
- ;; a concise way of doing it. (It would be nice to
- ;; declare it in the DEFKNOWN too.)
- ((simple-unboxed-array (*)) (vector-sap thing)))))
+ (etypecase thing
+ (system-area-pointer thing)
+ ;; FIXME: The code here rather relies on the simple
+ ;; unboxed array here having byte-sized entries. That
+ ;; should be asserted explicitly, I just haven't found
+ ;; a concise way of doing it. (It would be nice to
+ ;; declare it in the DEFKNOWN too.)
+ ((simple-unboxed-array (*)) (vector-sap thing)))))
(declare (inline sapify))
(without-gcing
(memmove (sap+ (sapify dst) dst-start)
- (sap+ (sapify src) src-start)
- (- dst-end dst-start)))
+ (sap+ (sapify src) src-start)
+ (- dst-end dst-start)))
(values)))
\f
;;;; transforms for EQL of floating point values
(deftransform eql ((x y) (double-float double-float))
'(and (= (double-float-low-bits x) (double-float-low-bits y))
- (= (double-float-high-bits x) (double-float-high-bits y))))
+ (= (double-float-high-bits x) (double-float-high-bits y))))
\f
;;;; modular functions
(let ((type (ecase class
(:unsigned 'unsigned-byte)
(:signed 'signed-byte))))
- `(progn
- (defknown ,name (integer (integer 0)) (,type ,width)
- (foldable flushable movable))
- (define-modular-fun-optimizer ash ((integer count) ,class :width width)
- (when (and (<= width ,width)
- (or (and (constant-lvar-p count)
- (plusp (lvar-value count)))
- (csubtypep (lvar-type count)
- (specifier-type '(and unsigned-byte fixnum)))))
- (cut-to-width integer ,class width)
- ',name))
+ `(progn
+ (defknown ,name (integer (integer 0)) (,type ,width)
+ (foldable flushable movable))
+ (define-modular-fun-optimizer ash ((integer count) ,class :width width)
+ (when (and (<= width ,width)
+ (or (and (constant-lvar-p count)
+ (plusp (lvar-value count)))
+ (csubtypep (lvar-type count)
+ (specifier-type '(and unsigned-byte fixnum)))))
+ (cut-to-width integer ,class width)
+ ',name))
(setf (gethash ',name (modular-class-versions (find-modular-class ',class)))
`(ash ,',width))))))
;; This should really be dependent on SB!VM:N-WORD-BITS, but since we
(defun ub32-strength-reduce-constant-multiply (arg num)
(declare (type (unsigned-byte 32) num))
(let ((adds 0) (shifts 0)
- (result nil) first-one)
+ (result nil) first-one)
(labels ((add (next-factor)
- (setf result
- (if result
+ (setf result
+ (if result
(progn (incf adds) `(+ ,result ,next-factor))
next-factor))))
(declare (inline add))
(dotimes (bitpos 32)
- (if first-one
- (when (not (logbitp bitpos num))
- (add (if (= (1+ first-one) bitpos)
- ;; There is only a single bit in the string.
- (progn (incf shifts) `(ash ,arg ,first-one))
- ;; There are at least two.
- (progn
- (incf adds)
- (incf shifts 2)
- `(- (ash ,arg ,bitpos)
- (ash ,arg ,first-one)))))
- (setf first-one nil))
- (when (logbitp bitpos num)
- (setf first-one bitpos))))
+ (if first-one
+ (when (not (logbitp bitpos num))
+ (add (if (= (1+ first-one) bitpos)
+ ;; There is only a single bit in the string.
+ (progn (incf shifts) `(ash ,arg ,first-one))
+ ;; There are at least two.
+ (progn
+ (incf adds)
+ (incf shifts 2)
+ `(- (ash ,arg ,bitpos)
+ (ash ,arg ,first-one)))))
+ (setf first-one nil))
+ (when (logbitp bitpos num)
+ (setf first-one bitpos))))
(when first-one
- (cond ((= first-one 31))
- ((= first-one 30) (incf shifts) (add `(ash ,arg 30)))
- (t
- (incf shifts 2)
- (incf adds)
- (add `(- (ash ,arg 31)
- (ash ,arg ,first-one)))))
- (incf shifts)
- (add `(ash ,arg 31))))
+ (cond ((= first-one 31))
+ ((= first-one 30) (incf shifts) (add `(ash ,arg 30)))
+ (t
+ (incf shifts 2)
+ (incf adds)
+ (add `(- (ash ,arg 31)
+ (ash ,arg ,first-one)))))
+ (incf shifts)
+ (add `(ash ,arg 31))))
(values (if (plusp adds)
`(logand ,result #.(1- (ash 1 32))) ; using modular arithmetic
result)