(in-package "SB!VM")
\f
+
+;; If chopping X to 32 bits and sign-extending is equal to the original X,
+;; return the chopped X, which the CPU will always treat as signed.
+;; Notably this allows MOST-POSITIVE-WORD to be an immediate constant.
+(defun immediate32-p (x)
+ (typecase x
+ ((signed-byte 32) x)
+ ((unsigned-byte 64)
+ (let ((chopped (sb!c::mask-signed-field 32 x)))
+ (and (= x (ldb (byte 64 0) chopped))
+ chopped)))
+ (t nil)))
+
+;; If 'immediate32-p' is true, use it; otherwise use a RIP-relative constant.
+;; I couldn't think of a more accurate name for this other than maybe
+;; 'signed-immediate32-or-rip-relativize' which is just too awful.
+(defun constantize (x)
+ (or (immediate32-p x)
+ (register-inline-constant :qword x)))
+
;;;; unary operations
(define-vop (fast-safe-arith-op)
(:note "inline (signed-byte 64) arithmetic"))
(define-vop (fast-fixnum-binop-c fast-safe-arith-op)
- (:args (x :target r :scs (any-reg)
- :load-if (or (not (typep y '(signed-byte 29)))
- (not (sc-is x any-reg control-stack)))))
+ (:args (x :target r :scs (any-reg) :load-if t))
(:info y)
(:arg-types tagged-num (:constant fixnum))
- (:results (r :scs (any-reg)
- :load-if (or (not (location= x r))
- (not (typep y '(signed-byte 29))))))
+ (:results (r :scs (any-reg) :load-if t))
(:result-types tagged-num)
(:note "inline fixnum arithmetic"))
(define-vop (fast-unsigned-binop-c fast-safe-arith-op)
- (:args (x :target r :scs (unsigned-reg)
- :load-if (or (not (typep y '(unsigned-byte 31)))
- (not (sc-is x unsigned-reg unsigned-stack)))))
+ (:args (x :target r :scs (unsigned-reg) :load-if t))
(:info y)
(:arg-types unsigned-num (:constant (unsigned-byte 64)))
- (:results (r :scs (unsigned-reg)
- :load-if (or (not (location= x r))
- (not (typep y '(unsigned-byte 31))))))
+ (:results (r :scs (unsigned-reg) :load-if t))
(:result-types unsigned-num)
(:note "inline (unsigned-byte 64) arithmetic"))
(define-vop (fast-signed-binop-c fast-safe-arith-op)
- (:args (x :target r :scs (signed-reg)
- :load-if (or (not (typep y '(signed-byte 32)))
- (not (sc-is x signed-reg signed-stack)))))
+ (:args (x :target r :scs (signed-reg) :load-if t))
(:info y)
(:arg-types signed-num (:constant (signed-byte 64)))
- (:results (r :scs (signed-reg)
- :load-if (or (not (location= x r))
- (not (typep y '(signed-byte 32))))))
+ (:results (r :scs (signed-reg) :load-if t))
(:result-types signed-num)
(:note "inline (signed-byte 64) arithmetic"))
-(macrolet ((define-binop (translate untagged-penalty op)
+(macrolet ((define-binop (translate untagged-penalty op
+ &key fixnum=>fixnum c/fixnum=>fixnum
+ signed=>signed c/signed=>signed
+ unsigned=>unsigned c/unsigned=>unsigned)
+
`(progn
(define-vop (,(symbolicate "FAST-" translate "/FIXNUM=>FIXNUM")
fast-fixnum-binop)
(:translate ,translate)
(:generator 2
- (move r x)
- (inst ,op r y)))
+ ,@(or fixnum=>fixnum `((move r x) (inst ,op r y)))))
(define-vop (,(symbolicate 'fast- translate '-c/fixnum=>fixnum)
fast-fixnum-binop-c)
(:translate ,translate)
(:generator 1
- (move r x)
- (inst ,op r (if (typep y '(signed-byte 29))
- (fixnumize y)
- (register-inline-constant :qword (fixnumize y))))))
+ ,@(or c/fixnum=>fixnum
+ `((move r x)
+ (inst ,op r (constantize (fixnumize y)))))))
(define-vop (,(symbolicate "FAST-" translate "/SIGNED=>SIGNED")
fast-signed-binop)
(:translate ,translate)
(:generator ,(1+ untagged-penalty)
- (move r x)
- (inst ,op r y)))
+ ,@(or signed=>signed `((move r x) (inst ,op r y)))))
(define-vop (,(symbolicate 'fast- translate '-c/signed=>signed)
fast-signed-binop-c)
(:translate ,translate)
(:generator ,untagged-penalty
- (move r x)
- (inst ,op r (if (typep y '(signed-byte 32))
- y
- (register-inline-constant :qword y)))))
+ ,@(or c/signed=>signed
+ `((move r x) (inst ,op r (constantize y))))))
(define-vop (,(symbolicate "FAST-"
translate
"/UNSIGNED=>UNSIGNED")
- fast-unsigned-binop)
+ fast-unsigned-binop)
(:translate ,translate)
(:generator ,(1+ untagged-penalty)
- (move r x)
- (inst ,op r y)))
+ ,@(or unsigned=>unsigned `((move r x) (inst ,op r y)))))
(define-vop (,(symbolicate 'fast-
translate
'-c/unsigned=>unsigned)
fast-unsigned-binop-c)
(:translate ,translate)
(:generator ,untagged-penalty
- (move r x)
- (inst ,op r (if (typep y '(unsigned-byte 31))
- y
- (register-inline-constant :qword y))))))))
+ ,@(or c/unsigned=>unsigned
+ `((move r x) (inst ,op r (constantize y)))))))))
;;(define-binop + 4 add)
(define-binop - 4 sub)
- (define-binop logand 2 and)
- (define-binop logior 2 or)
- (define-binop logxor 2 xor))
+
+ ;; The following have microoptimizations for some special cases
+ ;; not caught by the front end.
+
+ (define-binop logand 2 and
+ :c/unsigned=>unsigned
+ ((move r x)
+ (let ((y (constantize y)))
+ ;; ANDing with #xFFFF_FFFF_FFFF_FFFF is a no-op, other than
+ ;; the eflags state which we don't care about.
+ (unless (eql y -1) ; do nothing if this is true
+ (inst and r y)))))
+
+ (define-binop logior 2 or
+ :c/unsigned=>unsigned
+ ((let ((y (constantize y)))
+ (cond ((and (register-p r) (eql y -1)) ; special-case "OR reg, all-ones"
+ ;; I have yet to elicit this case. Can it happen?
+ (inst mov r -1))
+ (t
+ (move r x)
+ (inst or r y))))))
+
+ (define-binop logxor 2 xor
+ :c/unsigned=>unsigned
+ ((move r x)
+ (let ((y (constantize y)))
+ (if (eql y -1) ; special-case "XOR reg, [all-ones]"
+ (inst not r)
+ (inst xor r y))))))
;;; Special handling of add on the x86; can use lea to avoid a
;;; register load, otherwise it uses add.
+;;; FIXME: either inherit from fast-foo-binop or explain why not.
(define-vop (fast-+/fixnum=>fixnum fast-safe-arith-op)
(:translate +)
(:args (x :scs (any-reg) :target r
(define-vop (fast-+-c/fixnum=>fixnum fast-safe-arith-op)
(:translate +)
- (:args (x :target r :scs (any-reg)
- :load-if (or (not (typep y '(signed-byte 29)))
- (not (sc-is x any-reg control-stack)))))
+ (:args (x :target r :scs (any-reg) :load-if t))
(:info y)
(:arg-types tagged-num (:constant fixnum))
- (:results (r :scs (any-reg)
- :load-if (or (not (location= x r))
- (not (typep y '(signed-byte 29))))))
+ (:results (r :scs (any-reg) :load-if t))
(:result-types tagged-num)
(:note "inline fixnum arithmetic")
(:generator 1
- (cond ((and (sc-is x any-reg) (sc-is r any-reg) (not (location= x r))
- (typep y '(signed-byte 29)))
- (inst lea r (make-ea :qword :base x :disp (fixnumize y))))
- ((typep y '(signed-byte 29))
- (move r x)
- (inst add r (fixnumize y)))
- (t
- (move r x)
- (inst add r (register-inline-constant :qword (fixnumize y)))))))
+ (let ((y (fixnumize y)))
+ (cond ((and (not (location= x r))
+ (typep y '(signed-byte 32)))
+ (inst lea r (make-ea :qword :base x :disp y)))
+ (t
+ (move r x)
+ (inst add r (constantize y)))))))
(define-vop (fast-+/signed=>signed fast-safe-arith-op)
(:translate +)
(move r x)
(inst add r y)))))
-
;;;; Special logand cases: (logand signed unsigned) => unsigned
(define-vop (fast-logand/signed-unsigned=>unsigned
(y :scs (unsigned-reg unsigned-stack)))
(:arg-types signed-num unsigned-num))
+;; This special case benefits from the special case for c/unsigned=>unsigned.
+;; In particular, converting a (signed-byte 64) to (unsigned-byte 64) by
+;; way of (LDB (byte 64 0)) doesn't need an AND instruction.
(define-vop (fast-logand-c/signed-unsigned=>unsigned
fast-logand-c/unsigned=>unsigned)
- (:args (x :target r :scs (signed-reg)
- :load-if (or (not (typep y '(unsigned-byte 31)))
- (not (sc-is r signed-reg signed-stack)))))
+ (:args (x :target r :scs (signed-reg)))
(:arg-types signed-num (:constant (unsigned-byte 64))))
(define-vop (fast-logand/unsigned-signed=>unsigned
(move r x)
(cond ((= y 1)
(inst inc r))
- ((typep y '(signed-byte 32))
- (inst add r y))
(t
- (inst add r (register-inline-constant :qword y))))))))
+ (inst add r (constantize y))))))))
(define-vop (fast-+/unsigned=>unsigned fast-safe-arith-op)
(:translate +)
(move r x)
(cond ((= y 1)
(inst inc r))
- ((typep y '(unsigned-byte 31))
- (inst add r y))
(t
- (inst add r (register-inline-constant :qword y))))))))
+ (inst add r (constantize y))))))))
\f
;;;; multiplication and division
(:generator 30
(move eax x)
(inst cqo)
- (if (typep y '(signed-byte 29))
- (inst mov y-arg (fixnumize y))
- (setf y-arg (register-inline-constant :qword (fixnumize y))))
+ (inst mov y-arg (fixnumize y))
(inst idiv eax y-arg)
(if (location= quo eax)
(inst shl eax n-fixnum-tag-bits)
(:generator 32
(move eax x)
(inst xor edx edx)
- (if (typep y '(unsigned-byte 31))
- (inst mov y-arg y)
- (setf y-arg (register-inline-constant :qword y)))
+ (inst mov y-arg y)
(inst div eax y-arg)
(move quo eax)
(move rem edx)))
(:generator 32
(move eax x)
(inst cqo)
- (if (typep y '(signed-byte 32))
- (inst mov y-arg y)
- (setf y-arg (register-inline-constant :qword y)))
+ (inst mov y-arg y)
(inst idiv eax y-arg)
(move quo eax)
(move rem edx)))
DONE))
+#!+ash-right-vops
+(define-vop (fast-%ash/right/unsigned)
+ (:translate %ash/right)
+ (:policy :fast-safe)
+ (:args (number :scs (unsigned-reg) :target result)
+ (amount :scs (unsigned-reg) :target rcx))
+ (:arg-types unsigned-num unsigned-num)
+ (:results (result :scs (unsigned-reg) :from (:argument 0)))
+ (:result-types unsigned-num)
+ (:temporary (:sc signed-reg :offset rcx-offset :from (:argument 1)) rcx)
+ (:generator 4
+ (move result number)
+ (move rcx amount)
+ (inst shr result :cl)))
+
+#!+ash-right-vops
+(define-vop (fast-%ash/right/signed)
+ (:translate %ash/right)
+ (:policy :fast-safe)
+ (:args (number :scs (signed-reg) :target result)
+ (amount :scs (unsigned-reg) :target rcx))
+ (:arg-types signed-num unsigned-num)
+ (:results (result :scs (signed-reg) :from (:argument 0)))
+ (:result-types signed-num)
+ (:temporary (:sc signed-reg :offset rcx-offset :from (:argument 1)) rcx)
+ (:generator 4
+ (move result number)
+ (move rcx amount)
+ (inst sar result :cl)))
+
+#!+ash-right-vops
+(define-vop (fast-%ash/right/fixnum)
+ (:translate %ash/right)
+ (:policy :fast-safe)
+ (:args (number :scs (any-reg) :target result)
+ (amount :scs (unsigned-reg) :target rcx))
+ (:arg-types tagged-num unsigned-num)
+ (:results (result :scs (any-reg) :from (:argument 0)))
+ (:result-types tagged-num)
+ (:temporary (:sc signed-reg :offset rcx-offset :from (:argument 1)) rcx)
+ (:generator 3
+ (move result number)
+ (move rcx amount)
+ (inst sar result :cl)
+ (inst and result (lognot fixnum-tag-mask))))
+
(in-package "SB!C")
(defknown %lea (integer integer (member 1 2 4 8 16) (signed-byte 64))
(:result-types unsigned-num)
(:generator 28
(move res arg)
- (if (sc-is res unsigned-reg)
- (inst test res res)
- (inst cmp res 0))
+ (inst test res res)
(inst jmp :ge POS)
(inst not res)
POS
(zeroize res)
DONE))
+;; INTEGER-LENGTH is implemented by using the BSR instruction, which
+;; returns the position of the first 1-bit from the right. And that needs
+;; to be incremented to get the width of the integer, and BSR doesn't
+;; work on 0, so it needs a branch to handle 0.
+
+;; But fixnums are tagged by being shifted left n-fixnum-tag-bits times,
+;; untagging by shifting right n-fixnum-tag-bits-1 times (and if
+;; n-fixnum-tag-bits = 1, no shifting is required), will make the
+;; resulting integer one bit wider, making the increment unnecessary.
+;; Then, to avoid calling BSR on 0, OR the result with 1. That sets the
+;; first bit to 1, and if all other bits are 0, BSR will return 0,
+;; which is the correct value for INTEGER-LENGTH.
+(define-vop (positive-fixnum-len)
+ (:translate integer-length)
+ (:note "inline positive fixnum integer-length")
+ (:policy :fast-safe)
+ (:args (arg :scs (any-reg)))
+ (:arg-types positive-fixnum)
+ (:results (res :scs (unsigned-reg)))
+ (:result-types unsigned-num)
+ (:generator 24
+ (move res arg)
+ (when (> n-fixnum-tag-bits 1)
+ (inst shr res (1- n-fixnum-tag-bits)))
+ (inst or res 1)
+ (inst bsr res res)))
+
+(define-vop (fixnum-len)
+ (:translate integer-length)
+ (:note "inline fixnum integer-length")
+ (:policy :fast-safe)
+ (:args (arg :scs (any-reg) :target res))
+ (:arg-types tagged-num)
+ (:results (res :scs (unsigned-reg)))
+ (:result-types unsigned-num)
+ (:generator 25
+ (move res arg)
+ (when (> n-fixnum-tag-bits 1)
+ (inst sar res (1- n-fixnum-tag-bits)))
+ (inst test res res)
+ (inst jmp :ge POS)
+ (inst not res)
+ POS
+ (inst or res 1)
+ (inst bsr res res)))
+\f
(define-vop (unsigned-byte-64-count)
(:translate logcount)
(:note "inline (unsigned-byte 64) logcount")
(:affected)
(:policy :fast-safe))
-;;; constant variants are declared for 32 bits not 64 bits, because
-;;; loading a 64 bit constant is silly
-
(define-vop (fast-conditional/fixnum fast-conditional)
(:args (x :scs (any-reg)
:load-if (not (and (sc-is x control-stack)
(:note "inline fixnum comparison"))
(define-vop (fast-conditional-c/fixnum fast-conditional/fixnum)
- (:args (x :scs (any-reg)
- :load-if (or (not (typep y '(signed-byte 29)))
- (not (sc-is x any-reg control-stack)))))
+ (:args (x :scs (any-reg) :load-if t))
(:arg-types tagged-num (:constant fixnum))
(:info y))
(:note "inline (signed-byte 64) comparison"))
(define-vop (fast-conditional-c/signed fast-conditional/signed)
- (:args (x :scs (signed-reg)
- :load-if (or (not (typep y '(signed-byte 32)))
- (not (sc-is x signed-reg signed-stack)))))
+ (:args (x :scs (signed-reg) :load-if t))
(:arg-types signed-num (:constant (signed-byte 64)))
(:info y))
(:note "inline (unsigned-byte 64) comparison"))
(define-vop (fast-conditional-c/unsigned fast-conditional/unsigned)
- (:args (x :scs (unsigned-reg)
- :load-if (or (not (typep y '(unsigned-byte 31)))
- (not (sc-is x unsigned-reg unsigned-stack)))))
+ (:args (x :scs (unsigned-reg) :load-if t))
(:arg-types unsigned-num (:constant (unsigned-byte 64)))
(:info y))
+;; Stolen liberally from the x86 32-bit implementation.
+(macrolet ((define-logtest-vops ()
+ `(progn
+ ,@(loop for suffix in '(/fixnum -c/fixnum
+ /signed -c/signed
+ /unsigned -c/unsigned)
+ for cost in '(4 3 6 5 6 5)
+ collect
+ `(define-vop (,(symbolicate "FAST-LOGTEST" suffix)
+ ,(symbolicate "FAST-CONDITIONAL" suffix))
+ (:translate logtest)
+ (:conditional :ne)
+ (:generator ,cost
+ (emit-optimized-test-inst x
+ ,(case suffix
+ (-c/fixnum
+ `(constantize (fixnumize y)))
+ ((-c/signed -c/unsigned)
+ `(constantize y))
+ (t
+ 'y)))))))))
+ (define-logtest-vops))
+
+(defknown %logbitp (integer unsigned-byte) boolean
+ (movable foldable flushable always-translatable))
+
+;;; only for constant folding within the compiler
+(defun %logbitp (integer index)
+ (logbitp index integer))
+
+;;; too much work to do the non-constant case (maybe?)
+(define-vop (fast-logbitp-c/fixnum fast-conditional-c/fixnum)
+ (:translate %logbitp)
+ (:conditional :c)
+ (:arg-types tagged-num (:constant (integer 0 #.(- 63 n-fixnum-tag-bits))))
+ (:generator 4
+ (inst bt x (+ y n-fixnum-tag-bits))))
+
+(define-vop (fast-logbitp/signed fast-conditional/signed)
+ (:args (x :scs (signed-reg signed-stack))
+ (y :scs (signed-reg)))
+ (:translate %logbitp)
+ (:conditional :c)
+ (:generator 6
+ (inst bt x y)))
+
+(define-vop (fast-logbitp-c/signed fast-conditional-c/signed)
+ (:translate %logbitp)
+ (:conditional :c)
+ (:arg-types signed-num (:constant (integer 0 63)))
+ (:generator 5
+ (inst bt x y)))
+
+(define-vop (fast-logbitp/unsigned fast-conditional/unsigned)
+ (:args (x :scs (unsigned-reg unsigned-stack))
+ (y :scs (unsigned-reg)))
+ (:translate %logbitp)
+ (:conditional :c)
+ (:generator 6
+ (inst bt x y)))
+
+(define-vop (fast-logbitp-c/unsigned fast-conditional-c/unsigned)
+ (:translate %logbitp)
+ (:conditional :c)
+ (:arg-types unsigned-num (:constant (integer 0 63)))
+ (:generator 5
+ (inst bt x y)))
+
(macrolet ((define-conditional-vop (tran cond unsigned not-cond not-unsigned)
`(progn
,@(mapcar
(inst cmp x
,(case suffix
(-c/fixnum
- `(if (typep y '(signed-byte 29))
- (fixnumize y)
- (register-inline-constant
- :qword (fixnumize y))))
- (-c/signed
- `(if (typep y '(signed-byte 32))
- y
- (register-inline-constant
- :qword y)))
- (-c/unsigned
- `(if (typep y '(unsigned-byte 31))
- y
- (register-inline-constant
- :qword y)))
+ `(constantize (fixnumize y)))
+ ((-c/signed -c/unsigned)
+ `(constantize y))
(t 'y))))))
'(/fixnum -c/fixnum /signed -c/signed /unsigned -c/unsigned)
; '(/fixnum /signed /unsigned)
(:generator 5
(cond ((and (sc-is x signed-reg) (zerop y))
(inst test x x)) ; smaller instruction
- ((typep y '(signed-byte 32))
- (inst cmp x y))
(t
- (inst cmp x (register-inline-constant :qword y))))))
+ (inst cmp x (constantize y))))))
(define-vop (fast-if-eql/unsigned fast-conditional/unsigned)
(:translate eql)
(:generator 5
(cond ((and (sc-is x unsigned-reg) (zerop y))
(inst test x x)) ; smaller instruction
- ((typep y '(unsigned-byte 31))
- (inst cmp x y))
(t
- (inst cmp x (register-inline-constant :qword y))))))
+ (inst cmp x (constantize y))))))
;;; EQL/FIXNUM is funny because the first arg can be of any type, not just a
;;; known fixnum.
(:arg-types * tagged-num)
(:variant-cost 7))
-(define-vop (fast-eql-c/fixnum fast-conditional/fixnum)
- (:args (x :scs (any-reg)
- :load-if (or (not (typep y '(signed-byte 29)))
- (not (sc-is x any-reg descriptor-reg control-stack)))))
+(define-vop (fast-eql-c/fixnum fast-conditional-c/fixnum)
+ (:args (x :scs (any-reg) :load-if t))
(:arg-types tagged-num (:constant fixnum))
(:info y)
+ (:conditional :e)
+ (:policy :fast-safe)
(:translate eql)
(:generator 2
(cond ((and (sc-is x any-reg descriptor-reg) (zerop y))
(inst test x x)) ; smaller instruction
- ((typep y '(signed-byte 29))
- (inst cmp x (fixnumize y)))
(t
- (inst cmp x (register-inline-constant :qword (fixnumize y)))))))
+ (inst cmp x (constantize (fixnumize y)))))))
(define-vop (generic-eql-c/fixnum fast-eql-c/fixnum)
- (:args (x :scs (any-reg descriptor-reg)))
+ (:args (x :scs (any-reg descriptor-reg) :load-if t))
(:arg-types * (:constant fixnum))
(:variant-cost 6))
\f
(defmacro define-mod-binop-c ((name prototype) function)
`(define-vop (,name ,prototype)
(:args (x :target r :scs (unsigned-reg signed-reg)
- :load-if (not (and (or (sc-is x unsigned-stack)
- (sc-is x signed-stack))
- (or (sc-is r unsigned-stack)
- (sc-is r signed-stack))
- (location= x r)
- (typep y '(signed-byte 32))))))
+ :load-if t))
(:info y)
(:arg-types untagged-num (:constant (or (unsigned-byte 64) (signed-byte 64))))
(:results (r :scs (unsigned-reg signed-reg) :from (:argument 0)
- :load-if (not (and (or (sc-is x unsigned-stack)
- (sc-is x signed-stack))
- (or (sc-is r unsigned-stack)
- (sc-is r unsigned-stack))
- (location= x r)))))
+ :load-if t))
(:result-types unsigned-num)
(:translate ,function)))
(move result digit)
(move ecx count)
(inst shl result :cl)))
+
+(define-vop (logand-bignum/c)
+ (:translate logand)
+ (:policy :fast-safe)
+ (:args (x :scs (descriptor-reg)))
+ (:arg-types bignum (:constant word))
+ (:results (r :scs (unsigned-reg)))
+ (:info mask)
+ (:result-types unsigned-num)
+ (:generator 4
+ (let ((mask (constantize mask)))
+ (cond ((or (integerp mask)
+ (location= x r))
+ (loadw r x bignum-digits-offset other-pointer-lowtag)
+ (unless (eql mask -1)
+ (inst and r mask)))
+ (t
+ (inst mov r mask)
+ (inst and r (make-ea-for-object-slot x
+ bignum-digits-offset
+ other-pointer-lowtag)))))))
+
+;; Specialised mask-signed-field VOPs.
+(define-vop (mask-signed-field-word/c)
+ (:translate sb!c::mask-signed-field)
+ (:policy :fast-safe)
+ (:args (x :scs (signed-reg unsigned-reg) :target r))
+ (:arg-types (:constant (integer 0 64)) untagged-num)
+ (:results (r :scs (signed-reg)))
+ (:result-types signed-num)
+ (:info width)
+ (:generator 3
+ (cond ((zerop width)
+ (zeroize r))
+ ((= width 64)
+ (move r x))
+ ((member width '(32 16 8))
+ (inst movsx r (reg-in-size x (ecase width
+ (32 :dword)
+ (16 :word)
+ (8 :byte)))))
+ (t
+ (move r x)
+ (let ((delta (- n-word-bits width)))
+ (inst shl r delta)
+ (inst sar r delta))))))
+
+(define-vop (mask-signed-field-bignum/c)
+ (:translate sb!c::mask-signed-field)
+ (:policy :fast-safe)
+ (:args (x :scs (descriptor-reg) :target r))
+ (:arg-types (:constant (integer 0 64)) bignum)
+ (:results (r :scs (signed-reg)))
+ (:result-types signed-num)
+ (:info width)
+ (:generator 4
+ (cond ((zerop width)
+ (zeroize r))
+ ((member width '(8 16 32 64))
+ (ecase width
+ (64 (loadw r x bignum-digits-offset other-pointer-lowtag))
+ ((32 16 8)
+ (inst movsx r (make-ea (ecase width (32 :dword) (16 :word) (8 :byte))
+ :base x
+ :disp (- (* bignum-digits-offset n-word-bytes)
+ other-pointer-lowtag))))))
+ (t
+ (loadw r x bignum-digits-offset other-pointer-lowtag)
+ (let ((delta (- n-word-bits width)))
+ (inst shl r delta)
+ (inst sar r delta))))))
\f
;;;; static functions
projects / sbcl.git / blobdiff