;;; -*- Mode: LISP; Syntax: Common-Lisp; Base: 10; Package: x86 -*-
;;;
;;; **********************************************************************
;;; This code was written as part of the CMU Common Lisp project at
;;; Carnegie Mellon University, and has been placed in the public domain.
;;; If you want to use this code or any part of CMU Common Lisp, please contact
;;; Scott Fahlman or slisp-group@cs.cmu.edu.
;;;
(ext:file-comment
 "$Header: /project/cmucl/cvsroot/src/compiler/x86/arith.lisp,v 1.22 2008-08-18 20:40:07 rtoy Exp $")
;;;
;;; **********************************************************************
;;;
;;; This file contains the VM definition arithmetic VOPs for the x86.
;;;
;;; Written by William Lott.
;;;
;;; Debugged by Paul F. Werkowski Spring/Summer 1995.
;;; Enhancements/debugging by Douglas T. Crosher 1996,1997,2000.
;;; 

(in-package :x86)



;;;; Unary operations.

(define-vop (fast-safe-arith-op)
  (:policy :fast-safe)
  (:effects)
  (:affected))


(define-vop (fixnum-unop fast-safe-arith-op)
  (:args (x :scs (any-reg) :target res))
  (:results (res :scs (any-reg)))
  (:note "inline fixnum arithmetic")
  (:arg-types tagged-num)
  (:result-types tagged-num))

(define-vop (signed-unop fast-safe-arith-op)
  (:args (x :scs (signed-reg) :target res))
  (:results (res :scs (signed-reg)))
  (:note "inline (signed-byte 32) arithmetic")
  (:arg-types signed-num)
  (:result-types signed-num))

(define-vop (fast-negate/fixnum fixnum-unop)
  (:translate %negate)
  (:generator 1
    (move res x)
    (inst neg res)))

(define-vop (fast-negate/signed signed-unop)
  (:translate %negate)
  (:generator 2
    (move res x)
    (inst neg res)))

(define-vop (fast-lognot/fixnum fixnum-unop)
  (:translate lognot)
  (:generator 2
    (move res x)
    (inst xor res (fixnumize -1))))

(define-vop (fast-lognot/signed signed-unop)
  (:translate lognot)
  (:generator 1
    (move res x)
    (inst not res)))



;;;; Binary fixnum operations.

;;; Assume that any constant operand is the second arg...

(define-vop (fast-fixnum-binop fast-safe-arith-op)
  (:args (x :target r :scs (any-reg)
	    :load-if (not (and (sc-is x control-stack)
			       (sc-is y any-reg)
			       (sc-is r control-stack)
			       (location= x r))))
	 (y :scs (any-reg control-stack)))
  (:arg-types tagged-num tagged-num)
  (:results (r :scs (any-reg) :from (:argument 0)
	       :load-if (not (and (sc-is x control-stack)
				  (sc-is y any-reg)
				  (sc-is r control-stack)
				  (location= x r)))))
  (:result-types tagged-num)
  (:note "inline fixnum arithmetic"))

(define-vop (fast-unsigned-binop fast-safe-arith-op)
  (:args (x :target r :scs (unsigned-reg)
	    :load-if (not (and (sc-is x unsigned-stack)
			       (sc-is y unsigned-reg)
			       (sc-is r unsigned-stack)
			       (location= x r))))
	 (y :scs (unsigned-reg unsigned-stack)))
  (:arg-types unsigned-num unsigned-num)
  (:results (r :scs (unsigned-reg) :from (:argument 0)
	    :load-if (not (and (sc-is x unsigned-stack)
			       (sc-is y unsigned-reg)
			       (sc-is r unsigned-stack)
			       (location= x r)))))
  (:result-types unsigned-num)
  (:note "inline (unsigned-byte 32) arithmetic"))

(define-vop (fast-signed-binop fast-safe-arith-op)
  (:args (x :target r :scs (signed-reg)
	    :load-if (not (and (sc-is x signed-stack)
			       (sc-is y signed-reg)
			       (sc-is r signed-stack)
			       (location= x r))))
	 (y :scs (signed-reg signed-stack)))
  (:arg-types signed-num signed-num)
  (:results (r :scs (signed-reg) :from (:argument 0)
	    :load-if (not (and (sc-is x signed-stack)
			       (sc-is y signed-reg)
			       (sc-is r signed-stack)
			       (location= x r)))))
  (:result-types signed-num)
  (:note "inline (signed-byte 32) arithmetic"))

(define-vop (fast-fixnum-binop-c fast-safe-arith-op)
  (:args (x :target r :scs (any-reg control-stack)))
  (:info y)
  (:arg-types tagged-num (:constant (signed-byte 30)))
  (:results (r :scs (any-reg)
	       :load-if (not (location= x r))))
  (: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 unsigned-stack)))
  (:info y)
  (:arg-types unsigned-num (:constant (unsigned-byte 32)))
  (:results (r :scs (unsigned-reg)
	       :load-if (not (location= x r))))
  (:result-types unsigned-num)
  (:note "inline (unsigned-byte 32) arithmetic"))

(define-vop (fast-signed-binop-c fast-safe-arith-op)
  (:args (x :target r :scs (signed-reg signed-stack)))
  (:info y)
  (:arg-types signed-num (:constant (signed-byte 32)))
  (:results (r :scs (signed-reg)
	       :load-if (not (location= x r))))
  (:result-types signed-num)
  (:note "inline (signed-byte 32) arithmetic"))


(eval-when (compile load eval)

(defmacro define-binop (translate untagged-penalty op)
  `(progn
     (define-vop (,(symbolicate "FAST-" translate "/FIXNUM=>FIXNUM")
		  fast-fixnum-binop)
       (:translate ,translate)
       (:generator 2
	 (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 (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)))
     (define-vop (,(symbolicate 'fast- translate '-c/signed=>signed)
		  fast-signed-binop-c)
       (:translate ,translate)
       (:generator ,untagged-penalty
	 (move r x)
	 (inst ,op r y)))
     (define-vop (,(symbolicate "FAST-" translate "/UNSIGNED=>UNSIGNED")
		  fast-unsigned-binop)
       (:translate ,translate)
       (:generator ,(1+ untagged-penalty)
	 (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 y)))))

); eval-when



;(define-binop + 4 add)
(define-binop - 4 sub)
(define-binop logand 2 and)
(define-binop logior 2 or)
(define-binop logxor 2 xor)


;;; Special handling of add on the x86; can use lea to avoid a
;;; register load, otherwise it uses add.
(define-vop (fast-+/fixnum=>fixnum fast-safe-arith-op)
  (:translate +)
  (:args (x :scs (any-reg) :target r
	    :load-if (not (and (sc-is x control-stack)
			       (sc-is y any-reg)
			       (sc-is r control-stack)
			       (location= x r))))
	 (y :scs (any-reg control-stack)))
  (:arg-types tagged-num tagged-num)
  (:results (r :scs (any-reg) :from (:argument 0)
	       :load-if (not (and (sc-is x control-stack)
				  (sc-is y any-reg)
				  (sc-is r control-stack)
				  (location= x r)))))
  (:result-types tagged-num)
  (:note "inline fixnum arithmetic")
  (:generator 2
    (cond ((and (sc-is x any-reg) (sc-is y any-reg) (sc-is r any-reg)
		(not (location= x r)))
	   (inst lea r (make-ea :dword :base x :index y :scale 1)))
	  (t
	   (move r x)
	   (inst add r y)))))

(define-vop (fast-+-c/fixnum=>fixnum fast-safe-arith-op)
  (:translate +)
  (:args (x :target r :scs (any-reg control-stack)))
  (:info y)
  (:arg-types tagged-num (:constant (signed-byte 30)))
  (:results (r :scs (any-reg)
	       :load-if (not (location= x r))))
  (: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)))
	   (inst lea r (make-ea :dword :base x :disp (fixnumize y))))
	  (t
	   (move r x)
	   (inst add r (fixnumize y))))))

(define-vop (fast-+/signed=>signed fast-safe-arith-op)
  (:translate +)
  (:args (x :scs (signed-reg) :target r
	    :load-if (not (and (sc-is x signed-stack)
			       (sc-is y signed-reg)
			       (sc-is r signed-stack)
			       (location= x r))))
	 (y :scs (signed-reg signed-stack)))
  (:arg-types signed-num signed-num)
  (:results (r :scs (signed-reg) :from (:argument 0)
	       :load-if (not (and (sc-is x signed-stack)
				  (sc-is y signed-reg)
				  (location= x r)))))
  (:result-types signed-num)
  (:note "inline (signed-byte 32) arithmetic")
  (:generator 5
    (cond ((and (sc-is x signed-reg) (sc-is y signed-reg) (sc-is r signed-reg)
		(not (location= x r)))
	   (inst lea r (make-ea :dword :base x :index y :scale 1)))
	  (t
	   (move r x)
	   (inst add r y)))))

(define-vop (fast-+-c/signed=>signed fast-safe-arith-op)
  (:translate +)
  (:args (x :target r :scs (signed-reg signed-stack)))
  (:info y)
  (:arg-types signed-num (:constant (signed-byte 32)))
  (:results (r :scs (signed-reg)
	       :load-if (not (location= x r))))
  (:result-types signed-num)
  (:note "inline (signed-byte 32) arithmetic")
  (:generator 4
    (cond ((and (sc-is x signed-reg) (sc-is r signed-reg)
		(not (location= x r)))
	   (inst lea r (make-ea :dword :base x :disp y)))
	  (t
	   (move r x)
	   (if (= y 1)
	       (inst inc r)
	     (inst add r y))))))

(define-vop (fast-+/unsigned=>unsigned fast-safe-arith-op)
  (:translate +)
  (:args (x :scs (unsigned-reg) :target r
	    :load-if (not (and (sc-is x unsigned-stack)
			       (sc-is y unsigned-reg)
			       (sc-is r unsigned-stack)
			       (location= x r))))
	 (y :scs (unsigned-reg unsigned-stack)))
  (:arg-types unsigned-num unsigned-num)
  (:results (r :scs (unsigned-reg) :from (:argument 0)
	       :load-if (not (and (sc-is x unsigned-stack)
				  (sc-is y unsigned-reg)
				  (sc-is r unsigned-stack)
				  (location= x r)))))
  (:result-types unsigned-num)
  (:note "inline (unsigned-byte 32) arithmetic")
  (:generator 5
    (cond ((and (sc-is x unsigned-reg) (sc-is y unsigned-reg)
		(sc-is r unsigned-reg) (not (location= x r)))
	   (inst lea r (make-ea :dword :base x :index y :scale 1)))
	  (t
	   (move r x)
	   (inst add r y)))))

(define-vop (fast-+-c/unsigned=>unsigned fast-safe-arith-op)
  (:translate +)
  (:args (x :target r :scs (unsigned-reg unsigned-stack)))
  (:info y)
  (:arg-types unsigned-num (:constant (unsigned-byte 32)))
  (:results (r :scs (unsigned-reg)
	       :load-if (not (location= x r))))
  (:result-types unsigned-num)
  (:note "inline (unsigned-byte 32) arithmetic")
  (:generator 4
    (cond ((and (sc-is x unsigned-reg)
		(sc-is r unsigned-reg)
		(not (location= x r))
		(valid-displacement-p y))
	   (inst lea r (make-ea :dword :base x :disp y)))
	  (t
	   (move r x)
	   (if (= y 1)
	       (inst inc r)
	       (inst add r y))))))


;;;; Special logand cases: (logand signed unsigned) => unsigned

(define-vop (fast-logand/signed-unsigned=>unsigned
	     fast-logand/unsigned=>unsigned)
  (:args (x :target r :scs (signed-reg)
	    :load-if (not (and (sc-is x signed-stack)
			       (sc-is y unsigned-reg)
			       (sc-is r unsigned-stack)
			       (location= x r))))
	 (y :scs (unsigned-reg unsigned-stack)))
  (:arg-types signed-num unsigned-num))

(define-vop (fast-logand-c/signed-unsigned=>unsigned
	     fast-logand-c/unsigned=>unsigned)
  (:args (x :target r :scs (signed-reg signed-stack)))
  (:arg-types signed-num (:constant (unsigned-byte 32))))

(define-vop (fast-logand/unsigned-signed=>unsigned
	     fast-logand/unsigned=>unsigned)
  (:args (x :target r :scs (unsigned-reg)
	    :load-if (not (and (sc-is x unsigned-stack)
			       (sc-is y signed-reg)
			       (sc-is r unsigned-stack)
			       (location= x r))))
	 (y :scs (signed-reg signed-stack)))
  (:arg-types unsigned-num signed-num))


;;;; Multiplication and division.

(define-vop (fast-*/fixnum=>fixnum fast-safe-arith-op)
  (:translate *)
  ;; We need different loading characteristics.
  (:args (x :scs (any-reg) :target r)
	 (y :scs (any-reg control-stack)))
  (:arg-types tagged-num tagged-num)
  (:results (r :scs (any-reg) :from (:argument 0)))
  (:result-types tagged-num)
  (:note "inline fixnum arithmetic")
  (:generator 4
    (move r x)
    (inst sar r 2)
    (inst imul r y)))

(define-vop (fast-*-c/fixnum=>fixnum fast-safe-arith-op)
  (:translate *)
  ;; We need different loading characteristics.
  (:args (x :scs (any-reg control-stack)))
  (:info y)
  (:arg-types tagged-num (:constant (signed-byte 30)))
  (:results (r :scs (any-reg)))
  (:result-types tagged-num)
  (:note "inline fixnum arithmetic")
  (:generator 3
    (inst imul r x y)))

(define-vop (fast-*/signed=>signed fast-safe-arith-op)
  (:translate *)
  ;; We need different loading characteristics.
  (:args (x :scs (signed-reg) :target r)
	 (y :scs (signed-reg signed-stack)))
  (:arg-types signed-num signed-num)
  (:results (r :scs (signed-reg) :from (:argument 0)))
  (:result-types signed-num)
  (:note "inline (signed-byte 32) arithmetic")
  (:generator 5
    (move r x)
    (inst imul r y)))

(define-vop (fast-*-c/signed=>signed fast-safe-arith-op)
  (:translate *)
  ;; We need different loading characteristics.
  (:args (x :scs (signed-reg signed-stack)))
  (:info y)
  (:arg-types signed-num (:constant (signed-byte 32)))
  (:results (r :scs (signed-reg)))
  (:result-types signed-num)
  (:note "inline (signed-byte 32) arithmetic")
  (:generator 4
    (inst imul r x y)))

(define-vop (fast-*/unsigned=>unsigned fast-safe-arith-op)
  (:translate *)
  (:args (x :scs (unsigned-reg) :target eax)
	 (y :scs (unsigned-reg unsigned-stack)))
  (:arg-types unsigned-num unsigned-num)
  (:temporary (:sc unsigned-reg :offset eax-offset :target result
		   :from (:argument 0) :to :result) eax)
  (:temporary (:sc unsigned-reg :offset edx-offset
		   :from :eval :to :result) edx)
  (:ignore edx)
  (:results (result :scs (unsigned-reg)))
  (:result-types unsigned-num)
  (:note "inline (unsigned-byte 32) arithmetic")
  (:vop-var vop)
  (:save-p :compute-only)
  (:generator 6
    (move eax x)
    (inst mul eax y)
    (move result eax)))


(define-vop (fast-truncate/fixnum=>fixnum fast-safe-arith-op)
  (:translate truncate)
  (:args (x :scs (any-reg) :target eax)
	 (y :scs (any-reg control-stack)))
  (:arg-types tagged-num tagged-num)
  (:temporary (:sc signed-reg :offset eax-offset :target quo
		   :from (:argument 0) :to (:result 0)) eax)
  (:temporary (:sc unsigned-reg :offset edx-offset :target rem
		   :from (:argument 0) :to (:result 1)) edx)
  (:results (quo :scs (any-reg))
	    (rem :scs (any-reg)))
  (:result-types tagged-num tagged-num)
  (:note "inline fixnum arithmetic")
  (:vop-var vop)
  (:save-p :compute-only)
  (:generator 31
    (let ((zero (generate-error-code vop division-by-zero-error x y)))
      (if (sc-is y any-reg)
	  (inst test y y)  ; Smaller instruction
	  (inst cmp y 0))
      (inst jmp :eq zero))
    (move eax x)
    (inst cdq)
    (inst idiv eax y)
    (if (location= quo eax)
	(inst shl eax 2)
	(inst lea quo (make-ea :dword :index eax :scale 4)))
    (move rem edx)))

(define-vop (fast-truncate-c/fixnum=>fixnum fast-safe-arith-op)
  (:translate truncate)
  (:args (x :scs (any-reg) :target eax))
  (:info y)
  (:arg-types tagged-num (:constant (signed-byte 30)))
  (:temporary (:sc signed-reg :offset eax-offset :target quo
		   :from :argument :to (:result 0)) eax)
  (:temporary (:sc any-reg :offset edx-offset :target rem
		   :from :eval :to (:result 1)) edx)
  (:temporary (:sc any-reg :from :eval :to :result) y-arg)
  (:results (quo :scs (any-reg))
	    (rem :scs (any-reg)))
  (:result-types tagged-num tagged-num)
  (:note "inline fixnum arithmetic")
  (:vop-var vop)
  (:save-p :compute-only)
  (:generator 30
    (move eax x)
    (inst cdq)
    (inst mov y-arg (fixnumize y))
    (inst idiv eax y-arg)
    (if (location= quo eax)
	(inst shl eax 2)
	(inst lea quo (make-ea :dword :index eax :scale 4)))
    (move rem edx)))

(define-vop (fast-truncate/unsigned=>unsigned fast-safe-arith-op)
  (:translate truncate)
  (:args (x :scs (unsigned-reg) :target eax)
	 (y :scs (unsigned-reg signed-stack)))
  (:arg-types unsigned-num unsigned-num)
  (:temporary (:sc unsigned-reg :offset eax-offset :target quo
		   :from (:argument 0) :to (:result 0)) eax)
  (:temporary (:sc unsigned-reg :offset edx-offset :target rem
		   :from (:argument 0) :to (:result 1)) edx)
  (:results (quo :scs (unsigned-reg))
	    (rem :scs (unsigned-reg)))
  (:result-types unsigned-num unsigned-num)
  (:note "inline (unsigned-byte 32) arithmetic")
  (:vop-var vop)
  (:save-p :compute-only)
  (:generator 33
    (let ((zero (generate-error-code vop division-by-zero-error x y)))
      (if (sc-is y unsigned-reg)
	  (inst test y y)  ; Smaller instruction
	  (inst cmp y 0))
      (inst jmp :eq zero))
    (move eax x)
    (inst xor edx edx)
    (inst div eax y)
    (move quo eax)
    (move rem edx)))

(define-vop (fast-truncate-c/unsigned=>unsigned fast-safe-arith-op)
  (:translate truncate)
  (:args (x :scs (unsigned-reg) :target eax))
  (:info y)
  (:arg-types unsigned-num (:constant (unsigned-byte 32)))
  (:temporary (:sc unsigned-reg :offset eax-offset :target quo
		   :from :argument :to (:result 0)) eax)
  (:temporary (:sc unsigned-reg :offset edx-offset :target rem
		   :from :eval :to (:result 1)) edx)
  (:temporary (:sc unsigned-reg :from :eval :to :result) y-arg)
  (:results (quo :scs (unsigned-reg))
	    (rem :scs (unsigned-reg)))
  (:result-types unsigned-num unsigned-num)
  (:note "inline (unsigned-byte 32) arithmetic")
  (:vop-var vop)
  (:save-p :compute-only)
  (:generator 32
    (move eax x)
    (inst xor edx edx)
    (inst mov y-arg y)
    (inst div eax y-arg)
    (move quo eax)
    (move rem edx)))

(define-vop (fast-truncate/signed=>signed fast-safe-arith-op)
  (:translate truncate)
  (:args (x :scs (signed-reg) :target eax)
	 (y :scs (signed-reg signed-stack)))
  (:arg-types signed-num signed-num)
  (:temporary (:sc signed-reg :offset eax-offset :target quo
		   :from (:argument 0) :to (:result 0)) eax)
  (:temporary (:sc signed-reg :offset edx-offset :target rem
		   :from (:argument 0) :to (:result 1)) edx)
  (:results (quo :scs (signed-reg))
	    (rem :scs (signed-reg)))
  (:result-types signed-num signed-num)
  (:note "inline (signed-byte 32) arithmetic")
  (:vop-var vop)
  (:save-p :compute-only)
  (:generator 33
    (let ((zero (generate-error-code vop division-by-zero-error x y)))
      (if (sc-is y signed-reg)
	  (inst test y y)  ; Smaller instruction
	  (inst cmp y 0))
      (inst jmp :eq zero))
    (move eax x)
    (inst cdq)
    (inst idiv eax y)
    (move quo eax)
    (move rem edx)))

(define-vop (fast-truncate-c/signed=>signed fast-safe-arith-op)
  (:translate truncate)
  (:args (x :scs (signed-reg) :target eax))
  (:info y)
  (:arg-types signed-num (:constant (signed-byte 32)))
  (:temporary (:sc signed-reg :offset eax-offset :target quo
		   :from :argument :to (:result 0)) eax)
  (:temporary (:sc signed-reg :offset edx-offset :target rem
		   :from :eval :to (:result 1)) edx)
  (:temporary (:sc signed-reg :from :eval :to :result) y-arg)
  (:results (quo :scs (signed-reg))
	    (rem :scs (signed-reg)))
  (:result-types signed-num signed-num)
  (:note "inline (signed-byte 32) arithmetic")
  (:vop-var vop)
  (:save-p :compute-only)
  (:generator 32
    (move eax x)
    (inst cdq)
    (inst mov y-arg y)
    (inst idiv eax y-arg)
    (move quo eax)
    (move rem edx)))



;;;; Shifting
(define-vop (fast-ash-c/fixnum=>fixnum)
  (:translate ash)
  (:policy :fast-safe)
  (:args (number :scs (any-reg) :target result
		 :load-if (not (and (sc-is number any-reg control-stack)
				    (sc-is result any-reg control-stack)
				    (location= number result)))))
  (:info amount)
  (:arg-types tagged-num (:constant integer))
  (:results (result :scs (any-reg)
		    :load-if (not (and (sc-is number control-stack)
				       (sc-is result control-stack)
				       (location= number result)))))
  (:result-types tagged-num)
  (:note "inline ASH")
  (:generator 2
    (cond ((and (= amount 1) (not (location= number result)))
	   (inst lea result (make-ea :dword :index number :scale 2)))
	  ((and (= amount 2) (not (location= number result)))
	   (inst lea result (make-ea :dword :index number :scale 4)))
	  ((and (= amount 3) (not (location= number result)))
	   (inst lea result (make-ea :dword :index number :scale 8)))
	  (t
	   (move result number)
	   (cond ((plusp amount)
		  ;; We don't have to worry about overflow because of the
		  ;; result type restriction.
		  (inst shl result amount))
		 (t
		  ;; If the amount is greater than 31, only shift by 31.  We
		  ;; have to do this because the shift instructions only look
		  ;; at the low five bits of the result.
		  (inst sar result (min 31 (- amount)))
		  ;; Fixnum correction.
		  (inst and result #xfffffffc)))))))

(define-vop (fast-ash-left/fixnum=>fixnum)
  (:translate ash)
  (:args (number :scs (any-reg) :target result
		 :load-if (not (and (sc-is number control-stack)
				    (sc-is result control-stack)
				    (location= number result))))
	 (amount :scs (unsigned-reg) :target ecx))
  (:arg-types tagged-num positive-fixnum)
  (:temporary (:sc unsigned-reg :offset ecx-offset :from (:argument 1)) ecx)
  (:results (result :scs (any-reg) :from (:argument 0)
		    :load-if (not (and (sc-is number control-stack)
				       (sc-is result control-stack)
				       (location= number result)))))
  (:result-types tagged-num)
  (:policy :fast-safe)
  (:note "inline ASH")
  (:generator 3
    (move result number)
    (move ecx amount)
    ;; The result-type assures us that this shift will not overflow.
    (inst shl result :cl)))

(define-vop (fast-ash-c/unsigned=>unsigned)
	    (:translate ash)
  (:policy :fast-safe)
  (:args (number :scs (unsigned-reg) :target result
		 :load-if (not (and (sc-is number unsigned-stack)
				    (sc-is result unsigned-stack)
				    (location= number result)))))
  (:info amount)
  (:arg-types unsigned-num (:constant integer))
  (:results (result :scs (unsigned-reg)
		    :load-if (not (and (sc-is number unsigned-stack)
				       (sc-is result unsigned-stack)
				       (location= number result)))))
  (:result-types unsigned-num)
  (:note "inline ASH")
  (:generator 3
    (cond ((and (= amount 1) (not (location= number result)))
	   (inst lea result (make-ea :dword :index number :scale 2)))
	  ((and (= amount 2) (not (location= number result)))
	   (inst lea result (make-ea :dword :index number :scale 4)))
	  ((and (= amount 3) (not (location= number result)))
	   (inst lea result (make-ea :dword :index number :scale 8)))
	  (t
	   (move result number)
	   (cond ((plusp amount)
		  ;; We don't have to worry about overflow because of the
		  ;; result type restriction.
		  (inst shl result amount))
		 ((< amount -31)
		  (inst mov result 0))
		 (t
		  (inst shr result (- amount))))))))

(define-vop (fast-ash-c/signed=>signed)
  (:translate ash)
  (:policy :fast-safe)
  (:args (number :scs (signed-reg) :target result
		 :load-if (not (and (sc-is number signed-stack)
				    (sc-is result signed-stack)
				    (location= number result)))))
  (:info amount)
  (:arg-types signed-num (:constant integer))
  (:results (result :scs (signed-reg)
		    :load-if (not (and (sc-is number signed-stack)
				       (sc-is result signed-stack)
				       (location= number result)))))
  (:result-types signed-num)
  (:note "inline ASH")
  (:generator 3
    (cond ((and (= amount 1) (not (location= number result)))
	   (inst lea result (make-ea :dword :index number :scale 2)))
	  ((and (= amount 2) (not (location= number result)))
	   (inst lea result (make-ea :dword :index number :scale 4)))
	  ((and (= amount 3) (not (location= number result)))
	   (inst lea result (make-ea :dword :index number :scale 8)))
	  (t
	   (move result number)
	   (cond ((plusp amount)
		  ;; We don't have to worry about overflow because of the
		  ;; result type restriction.
		  (inst shl result amount))
		 (t
		  ;; If the amount is greater than 31, only shift by 31.  We
		  ;; have to do this because the shift instructions only look
		  ;; at the low five bits of the result.
		  (inst sar result (min 31 (- amount)))))))))

(define-vop (fast-ash-left/unsigned=>unsigned)
  (:translate ash)
  (:args (number :scs (unsigned-reg) :target result
		 :load-if (not (and (sc-is number unsigned-stack)
				    (sc-is result unsigned-stack)
				    (location= number result))))
	 (amount :scs (unsigned-reg) :target ecx))
  (:arg-types unsigned-num positive-fixnum)
  (:temporary (:sc unsigned-reg :offset ecx-offset :from (:argument 1)) ecx)
  (:results (result :scs (unsigned-reg) :from (:argument 0)
		    :load-if (not (and (sc-is number unsigned-stack)
				       (sc-is result unsigned-stack)
				       (location= number result)))))
  (:result-types unsigned-num)
  (:policy :fast-safe)
  (:note "inline ASH")
  (:generator 4
    (move result number)
    (move ecx amount)
    ;; The result-type assures us that this shift will not overflow.
    (inst shl result :cl)))

(define-vop (fast-ash-left/signed=>signed)
  (:translate ash)
  (:args (number :scs (signed-reg) :target result
		 :load-if (not (and (sc-is number signed-stack)
				    (sc-is result signed-stack)
				    (location= number result))))
	 (amount :scs (unsigned-reg) :target ecx))
  (:arg-types signed-num positive-fixnum)
  (:temporary (:sc unsigned-reg :offset ecx-offset :from (:argument 1)) ecx)
  (:results (result :scs (signed-reg) :from (:argument 0)
		    :load-if (not (and (sc-is number signed-stack)
				       (sc-is result signed-stack)
				       (location= number result)))))
  (:result-types signed-num)
  (:policy :fast-safe)
  (:note "inline ASH")
  (:generator 4
    (move result number)
    (move ecx amount)
    ;; The result-type assures us that this shift will not overflow.
    (inst shl result :cl)))

(define-vop (fast-ash/unsigned=>unsigned)
	    (:translate ash)
  (:policy :fast-safe)
  (:args (number :scs (unsigned-reg) :target result)
	 (amount :scs (signed-reg) :target ecx))
  (:arg-types unsigned-num signed-num)
  (:results (result :scs (unsigned-reg) :from (:argument 0)))
  (:result-types unsigned-num)
  (:temporary (:sc signed-reg :offset ecx-offset :from (:argument 1)) ecx)
  (:note "inline ASH")
  (:generator 5
    (move result number)
    (move ecx amount)
    (inst or ecx ecx)
    (inst jmp :ns POSITIVE)
    (inst neg ecx)
    (inst cmp ecx 31)
    (inst jmp :be OKAY)
    (inst xor result result)
    (inst jmp DONE)
    OKAY
    (inst shr result :cl)
    (inst jmp DONE)
    
    POSITIVE
    ;; The result-type assures us that this shift will not overflow.
    (inst shl result :cl)
    
    DONE))

(define-vop (fast-ash/signed=>signed)
  (:translate ash)
  (:policy :fast-safe)
  (:args (number :scs (signed-reg) :target result)
	 (amount :scs (signed-reg) :target ecx))
  (:arg-types signed-num signed-num)
  (:results (result :scs (signed-reg) :from (:argument 0)))
  (:result-types signed-num)
  (:temporary (:sc signed-reg :offset ecx-offset :from (:argument 1)) ecx)
  (:note "inline ASH")
  (:generator 5
    (move result number)
    (move ecx amount)
    (inst or ecx ecx)
    (inst jmp :ns positive)
    (inst neg ecx)
    (inst cmp ecx 31)
    (inst jmp :be okay)
    (inst mov ecx 31)
    OKAY
    (inst sar result :cl)
    (inst jmp done)
      
    POSITIVE
    ;; The result-type assures us that this shift will not overflow.
    (inst shl result :cl)
      
    DONE))


;;; note documentation for this function is wrong - rtfm
(define-vop (signed-byte-32-len)
  (:translate integer-length)
  (:note "inline (signed-byte 32) integer-length")
  (:policy :fast-safe)
  (:args (arg :scs (signed-reg) :target res))
  (:arg-types signed-num)
  (:results (res :scs (any-reg)))
  (:result-types positive-fixnum)
  (:generator 30
    (move res arg)
    (inst cmp res 0)
    (inst jmp :ge POS)
    (inst not res)
    POS
    (inst bsr res res)
    (inst jmp :z zero)
    (inst inc res)
    (inst shl res 2)
    (inst jmp done)
    ZERO
    (inst xor res res)
    DONE))

(define-vop (unsigned-byte-32-count)
  (:translate logcount)
  (:note "inline (unsigned-byte 32) logcount")
  (:policy :fast-safe)
  (:args (arg :scs (unsigned-reg)))
  (:arg-types unsigned-num)
  (:results (result :scs (unsigned-reg)))
  (:result-types positive-fixnum)
  (:temporary (:sc unsigned-reg :from (:argument 0)) temp)
  (:generator 30
    (move result arg)

    (inst mov temp result)
    (inst shr temp 1)
    (inst and result #x55555555)
    (inst and temp #x55555555)
    (inst add result temp)

    (inst mov temp result)
    (inst shr temp 2)
    (inst and result #x33333333)
    (inst and temp #x33333333)
    (inst add result temp)

    (inst mov temp result)
    (inst shr temp 4)
    (inst and result #x0f0f0f0f)
    (inst and temp #x0f0f0f0f)
    (inst add result temp)

    (inst mov temp result)
    (inst shr temp 8)
    (inst and result #x00ff00ff)
    (inst and temp #x00ff00ff)
    (inst add result temp)

    (inst mov temp result)
    (inst shr temp 16)
    (inst and result #x0000ffff)
    (inst and temp #x0000ffff)
    (inst add result temp)))



;;;; Binary conditional VOPs:

(define-vop (fast-conditional)
  (:conditional)
  (:info target not-p)
  (:effects)
  (:affected)
  (:policy :fast-safe))

(define-vop (fast-conditional/fixnum fast-conditional)
  (:args (x :scs (any-reg)
	    :load-if (not (and (sc-is x control-stack)
			       (sc-is y any-reg))))
	 (y :scs (any-reg control-stack)))
  (:arg-types tagged-num tagged-num)
  (:note "inline fixnum comparison"))

(define-vop (fast-conditional-c/fixnum fast-conditional/fixnum)
  (:args (x :scs (any-reg control-stack)))
  (:arg-types tagged-num (:constant (signed-byte 30)))
  (:info target not-p y))

(define-vop (fast-conditional/signed fast-conditional)
  (:args (x :scs (signed-reg)
	    :load-if (not (and (sc-is x signed-stack)
			       (sc-is y signed-reg))))
	 (y :scs (signed-reg signed-stack)))
  (:arg-types signed-num signed-num)
  (:note "inline (signed-byte 32) comparison"))

(define-vop (fast-conditional-c/signed fast-conditional/signed)
  (:args (x :scs (signed-reg signed-stack)))
  (:arg-types signed-num (:constant (signed-byte 32)))
  (:info target not-p y))

(define-vop (fast-conditional/unsigned fast-conditional)
  (:args (x :scs (unsigned-reg)
	    :load-if (not (and (sc-is x unsigned-stack)
			       (sc-is y unsigned-reg))))
	 (y :scs (unsigned-reg unsigned-stack)))
  (:arg-types unsigned-num unsigned-num)
  (:note "inline (unsigned-byte 32) comparison"))

(define-vop (fast-conditional-c/unsigned fast-conditional/unsigned)
  (:args (x :scs (unsigned-reg unsigned-stack)))
  (:arg-types unsigned-num (:constant (unsigned-byte 32)))
  (:info target not-p y))


(defmacro define-conditional-vop (tran cond unsigned not-cond not-unsigned)
  `(progn
     ,@(mapcar
	#'(lambda (suffix cost signed)
	    `(define-vop (,(intern (format nil "~:@(FAST-IF-~A~A~)"
					   tran suffix))
			  ,(intern
			    (format nil "~:@(FAST-CONDITIONAL~A~)"
				    suffix)))
	       (:translate ,tran)
	       (:generator ,cost
		 (inst cmp x
		       ,(if (eq suffix '-c/fixnum) '(fixnumize y) 'y))
		 (inst jmp (if not-p
			       ,(if signed not-cond not-unsigned)
			     ,(if signed cond unsigned))
		       target))))
	'(/fixnum -c/fixnum /signed -c/signed /unsigned -c/unsigned)
	'(4 3 6 5 6 5)
	'(t t t t nil nil))))

(define-conditional-vop < :l :b :ge :ae)

(define-conditional-vop > :g :a :le :be)

(define-vop (fast-if-eql/signed fast-conditional/signed)
  (:translate eql)
  (:generator 6
    (inst cmp x y)
    (inst jmp (if not-p :ne :e) target)))

(define-vop (fast-if-eql-c/signed fast-conditional-c/signed)
  (:translate eql)
  (:generator 5
    (cond ((and (sc-is x signed-reg) (zerop y))
	   (inst test x x))  ; Smaller instruction
	  (t
	   (inst cmp x y)))
    (inst jmp (if not-p :ne :e) target)))

(define-vop (fast-if-eql/unsigned fast-conditional/unsigned)
  (:translate eql)
  (:generator 6
    (inst cmp x y)
    (inst jmp (if not-p :ne :e) target)))

(define-vop (fast-if-eql-c/unsigned fast-conditional-c/unsigned)
  (:translate eql)
  (:generator 5
    (cond ((and (sc-is x unsigned-reg) (zerop y))
	   (inst test x x))  ; Smaller instruction
	  (t
	   (inst cmp x y)))
    (inst jmp (if not-p :ne :e) target)))

;;; EQL/FIXNUM is funny because the first arg can be of any type, not just a
;;; known fixnum.

;;; These versions specify a fixnum restriction on their first arg.  We have
;;; also generic-eql/fixnum VOPs which are the same, but have no restriction on
;;; the first arg and a higher cost.  The reason for doing this is to prevent
;;; fixnum specific operations from being used on word integers, spuriously
;;; consing the argument.
;;;

(define-vop (fast-eql/fixnum fast-conditional)
  (:args (x :scs (any-reg)
	    :load-if (not (and (sc-is x control-stack)
			       (sc-is y any-reg))))
	 (y :scs (any-reg control-stack)))
  (:arg-types tagged-num tagged-num)
  (:note "inline fixnum comparison")
  (:translate eql)
  (:generator 4
    (inst cmp x y)
    (inst jmp (if not-p :ne :e) target)))
;;;
(define-vop (generic-eql/fixnum fast-eql/fixnum)
  (:args (x :scs (any-reg descriptor-reg)
	    :load-if (not (and (sc-is x control-stack)
			       (sc-is y any-reg))))
	 (y :scs (any-reg control-stack)))
  (:arg-types * tagged-num)
  (:variant-cost 7))

(define-vop (fast-eql-c/fixnum fast-conditional/fixnum)
  (:args (x :scs (any-reg control-stack)))
  (:arg-types tagged-num (:constant (signed-byte 30)))
  (:info target not-p y)
  (:translate eql)
  (:generator 2
    (cond ((and (sc-is x any-reg descriptor-reg) (zerop y))
	   (inst test x x))  ; Smaller instruction
	  (t
	   (inst cmp x (fixnumize y))))
    (inst jmp (if not-p :ne :e) target)))
;;;
(define-vop (generic-eql-c/fixnum fast-eql-c/fixnum)
  (:args (x :scs (any-reg descriptor-reg control-stack)))
  (:arg-types * (:constant (signed-byte 30)))
  (:variant-cost 6))


;;;; 32-bit logical operations

(define-vop (merge-bits)
  (:translate merge-bits)
  (:args (shift :scs (signed-reg unsigned-reg) :target ecx)
	 (prev :scs (unsigned-reg) :target result)
	 (next :scs (unsigned-reg)))
  (:arg-types tagged-num unsigned-num unsigned-num)
  (:temporary (:sc signed-reg :offset ecx-offset :from (:argument 0)) ecx)
  (:results (result :scs (unsigned-reg) :from (:argument 1)))
  (:result-types unsigned-num)
  (:policy :fast-safe)
  (:generator 4
    (move ecx shift)
    (move result prev)
    (inst shrd result next :cl)))

(define-vop (32bit-logical)
  (:args (x :scs (unsigned-reg) :target r
	    :load-if (not (and (sc-is x unsigned-stack)
			       (sc-is r unsigned-stack)
			       (location= x r))))
	 (y :scs (unsigned-reg)
	    :load-if (or (not (sc-is y unsigned-stack))
			 (and (sc-is x unsigned-stack)
			      (sc-is y unsigned-stack)
			      (location= x r)))))
  (:arg-types unsigned-num unsigned-num)
  (:results (r :scs (unsigned-reg)  :from (:argument 0)
	       :load-if (not (and (sc-is x unsigned-stack)
				  (sc-is r unsigned-stack)
				  (location= x r)))))
  (:result-types unsigned-num)
  (:policy :fast-safe))

(define-vop (32bit-logical-not)
  (:translate 32bit-logical-not)
  (:args (x :scs (unsigned-reg) :target r
	    :load-if (not (and (sc-is x unsigned-stack)
			       (sc-is r unsigned-stack)
			       (location= x r)))))
  (:arg-types unsigned-num)
  (:results (r :scs (unsigned-reg)
	       :load-if (not (and (sc-is x unsigned-stack)
				  (sc-is r unsigned-stack)
				  (location= x r)))))
  (:result-types unsigned-num)
  (:policy :fast-safe)
  (:generator 1
    (move r x)
    (inst not r)))

(define-vop (32bit-logical-and 32bit-logical)
  (:translate 32bit-logical-and)
  (:generator 1
    (move r x)
    (inst and r y)))

(def-source-transform 32bit-logical-nand (x y)
  `(32bit-logical-not (32bit-logical-and ,x ,y)))

(define-vop (32bit-logical-or 32bit-logical)
  (:translate 32bit-logical-or)
  (:generator 1
    (move r x)
    (inst or r y)))

(def-source-transform 32bit-logical-nor (x y)
  `(32bit-logical-not (32bit-logical-or ,x ,y)))

(define-vop (32bit-logical-xor 32bit-logical)
  (:translate 32bit-logical-xor)
  (:generator 1
    (move r x)
    (inst xor r y)))

(def-source-transform 32bit-logical-eqv (x y)
  `(32bit-logical-not (32bit-logical-xor ,x ,y)))

(def-source-transform 32bit-logical-orc1 (x y)
  `(32bit-logical-or (32bit-logical-not ,x) ,y))

(def-source-transform 32bit-logical-orc2 (x y)
  `(32bit-logical-or ,x (32bit-logical-not ,y)))

(def-source-transform 32bit-logical-andc1 (x y)
  `(32bit-logical-and (32bit-logical-not ,x) ,y))

(def-source-transform 32bit-logical-andc2 (x y)
  `(32bit-logical-and ,x (32bit-logical-not ,y)))

;;; Only the lower 5 bits of the shift amount are significant.
(define-vop (shift-towards-someplace)
  (:policy :fast-safe)
  (:args (num :scs (unsigned-reg) :target r)
	 (amount :scs (signed-reg) :target ecx))
  (:arg-types unsigned-num tagged-num)
  (:temporary (:sc signed-reg :offset ecx-offset :from (:argument 1)) ecx)
  (:results (r :scs (unsigned-reg) :from (:argument 0)))
  (:result-types unsigned-num))

(define-vop (shift-towards-start shift-towards-someplace)
  (:translate shift-towards-start)
  (:note "SHIFT-TOWARDS-START")
  (:generator 1
    (move r num)
    (move ecx amount)
    (inst shr r :cl)))

(define-vop (shift-towards-end shift-towards-someplace)
  (:translate shift-towards-end)
  (:note "SHIFT-TOWARDS-END")
  (:generator 1
    (move r num)
    (move ecx amount)
    (inst shl r :cl)))



;;;; Bignum stuff.

(define-vop (bignum-length get-header-data)
  (:translate bignum::%bignum-length)
  (:policy :fast-safe))

(define-vop (bignum-set-length set-header-data)
  (:translate bignum::%bignum-set-length)
  (:policy :fast-safe))

(define-full-reffer bignum-ref * bignum-digits-offset other-pointer-type
  (unsigned-reg) unsigned-num bignum::%bignum-ref)

(define-full-setter bignum-set * bignum-digits-offset other-pointer-type
  (unsigned-reg) unsigned-num bignum::%bignum-set)

(define-vop (digit-0-or-plus)
  (:translate bignum::%digit-0-or-plusp)
  (:policy :fast-safe)
  (:args (digit :scs (unsigned-reg)))
  (:arg-types unsigned-num)
  (:conditional)
  (:info target not-p)
  (:generator 3
    (inst or digit digit)
    (inst jmp (if not-p :s :ns) target)))


;;; For add and sub with carry the sc of carry argument is any-reg so
;;; the it may be passed as a fixnum or word and thus may be 0, 1, or
;;; 4. This is easy to deal with and may save a fixnum-word
;;; conversion.
;;;
(define-vop (add-w/carry)
  (:translate bignum::%add-with-carry)
  (:policy :fast-safe)
  (:args (a :scs (unsigned-reg) :target result)
	 (b :scs (unsigned-reg unsigned-stack) :to :eval)
	 (c :scs (any-reg) :target temp))
  (:arg-types unsigned-num unsigned-num positive-fixnum)
  (:temporary (:sc any-reg :from (:argument 2) :to :eval) temp)
  (:results (result :scs (unsigned-reg) :from (:argument 0))
	    (carry :scs (unsigned-reg)))
  (:result-types unsigned-num positive-fixnum)
  (:generator 4
    (move result a)
    (move temp c)
    (inst neg temp) ; Set the carry flag to 0 if c=0 else to 1
    (inst adc result b)
    (inst mov carry 0)
    (inst adc carry carry)))

;;; Note: the borrow is the oppostite of the x86 convention - 1 for no
;;; borrow and 0 for a borrow.
(define-vop (sub-w/borrow)
  (:translate bignum::%subtract-with-borrow)
  (:policy :fast-safe)
  (:args (a :scs (unsigned-reg) :to :eval :target result)
	 (b :scs (unsigned-reg unsigned-stack) :to :result)
	 (c :scs (any-reg control-stack)))
  (:arg-types unsigned-num unsigned-num positive-fixnum)
  (:results (result :scs (unsigned-reg) :from :eval)
	    (borrow :scs (unsigned-reg)))
  (:result-types unsigned-num positive-fixnum)
  (:generator 5
    (inst cmp c 1) ; Set the carry flag to 1 if c=0 else to 0
    (move result a)
    (inst sbb result b)
    (inst mov borrow 0)
    (inst adc borrow borrow)
    (inst xor borrow 1)))


(define-vop (bignum-mult-and-add-3-arg)
  (:translate bignum::%multiply-and-add)
  (:policy :fast-safe)
  (:args (x :scs (unsigned-reg) :target eax)
	 (y :scs (unsigned-reg unsigned-stack))
	 (carry-in :scs (unsigned-reg unsigned-stack)))
  (:arg-types unsigned-num unsigned-num unsigned-num)
  (:temporary (:sc unsigned-reg :offset eax-offset :from (:argument 0)
		   :to (:result 1) :target lo) eax)
  (:temporary (:sc unsigned-reg :offset edx-offset :from (:argument 1)
		   :to (:result 0) :target hi) edx)
  (:results (hi :scs (unsigned-reg))
	    (lo :scs (unsigned-reg)))
  (:result-types unsigned-num unsigned-num)
  (:generator 20
    (move eax x)
    (inst mul eax y)
    (inst add eax carry-in)
    (inst adc edx 0)
    (move hi edx)
    (move lo eax)))

(define-vop (bignum-mult-and-add-4-arg)
  (:translate bignum::%multiply-and-add)
  (:policy :fast-safe)
  (:args (x :scs (unsigned-reg) :target eax)
	 (y :scs (unsigned-reg unsigned-stack))
	 (prev :scs (unsigned-reg unsigned-stack))
	 (carry-in :scs (unsigned-reg unsigned-stack)))
  (:arg-types unsigned-num unsigned-num unsigned-num unsigned-num)
  (:temporary (:sc unsigned-reg :offset eax-offset :from (:argument 0)
		   :to (:result 1) :target lo) eax)
  (:temporary (:sc unsigned-reg :offset edx-offset :from (:argument 1)
		   :to (:result 0) :target hi) edx)
  (:results (hi :scs (unsigned-reg))
	    (lo :scs (unsigned-reg)))
  (:result-types unsigned-num unsigned-num)
  (:generator 20
    (move eax x)
    (inst mul eax y)
    (inst add eax prev)
    (inst adc edx 0)
    (inst add eax carry-in)
    (inst adc edx 0)
    (move hi edx)
    (move lo eax)))


(define-vop (bignum-mult)
  (:translate bignum::%multiply)
  (:policy :fast-safe)
  (:args (x :scs (unsigned-reg) :target eax)
	 (y :scs (unsigned-reg unsigned-stack)))
  (:arg-types unsigned-num unsigned-num)
  (:temporary (:sc unsigned-reg :offset eax-offset :from (:argument 0)
		   :to (:result 1) :target lo) eax)
  (:temporary (:sc unsigned-reg :offset edx-offset :from (:argument 1)
		   :to (:result 0) :target hi) edx)
  (:results (hi :scs (unsigned-reg))
	    (lo :scs (unsigned-reg)))
  (:result-types unsigned-num unsigned-num)
  (:generator 20
    (move eax x)
    (inst mul eax y)
    (move hi edx)
    (move lo eax)))

(define-vop (bignum-lognot)
  (:translate bignum::%lognot)
  (:policy :fast-safe)
  (:args (x :scs (unsigned-reg unsigned-stack) :target r))
  (:arg-types unsigned-num)
  (:results (r :scs (unsigned-reg)
	       :load-if (not (location= x r))))
  (:result-types unsigned-num)
  (:generator 1
    (move r x)
    (inst not r)))

(define-vop (fixnum-to-digit)
  (:translate bignum::%fixnum-to-digit)
  (:policy :fast-safe)
  (:args (fixnum :scs (any-reg control-stack) :target digit))
  (:arg-types tagged-num)
  (:results (digit :scs (unsigned-reg)
		   :load-if (not (and (sc-is fixnum control-stack)
				      (sc-is digit unsigned-stack)
				      (location= fixnum digit)))))
  (:result-types unsigned-num)
  (:generator 1
    (move digit fixnum)
    (inst sar digit 2)))

(define-vop (bignum-floor)
  (:translate bignum::%floor)
  (:policy :fast-safe)
  (:args (div-high :scs (unsigned-reg) :target edx)
	 (div-low :scs (unsigned-reg) :target eax)
	 (divisor :scs (unsigned-reg unsigned-stack)))
  (:arg-types unsigned-num unsigned-num unsigned-num)
  (:temporary (:sc unsigned-reg :offset eax-offset :from (:argument 1)
		   :to (:result 0) :target quo) eax)
  (:temporary (:sc unsigned-reg :offset edx-offset :from (:argument 0)
		   :to (:result 1) :target rem) edx)
  (:results (quo :scs (unsigned-reg))
	    (rem :scs (unsigned-reg)))
  (:result-types unsigned-num unsigned-num)
  (:generator 300
    (move edx div-high)
    (move eax div-low)
    (inst div eax divisor)
    (move quo eax)
    (move rem edx)))

(define-vop (signify-digit)
  (:translate bignum::%fixnum-digit-with-correct-sign)
  (:policy :fast-safe)
  (:args (digit :scs (unsigned-reg unsigned-stack) :target res))
  (:arg-types unsigned-num)
  (:results (res :scs (any-reg signed-reg)
		 :load-if (not (and (sc-is digit unsigned-stack)
				    (sc-is res control-stack signed-stack)
				    (location= digit res)))))
  (:result-types signed-num)
  (:generator 1
    (move res digit)
    (when (sc-is res any-reg control-stack)
      (inst shl res 2))))

(define-vop (digit-ashr)
  (:translate bignum::%ashr)
  (:policy :fast-safe)
  (:args (digit :scs (unsigned-reg unsigned-stack) :target result)
	 (count :scs (unsigned-reg) :target ecx))
  (:arg-types unsigned-num positive-fixnum)
  (:temporary (:sc unsigned-reg :offset ecx-offset :from (:argument 1)) ecx)
  (:results (result :scs (unsigned-reg) :from (:argument 0)
		    :load-if (not (and (sc-is result unsigned-stack)
				       (location= digit result)))))
  (:result-types unsigned-num)
  (:generator 1
    (move result digit)
    (move ecx count)
    (inst sar result :cl)))

(define-vop (digit-lshr digit-ashr)
  (:translate bignum::%digit-logical-shift-right)
  (:generator 1
    (move result digit)
    (move ecx count)
    (inst shr result :cl)))

(define-vop (digit-ashl digit-ashr)
  (:translate bignum::%ashl)
  (:generator 1
    (move result digit)
    (move ecx count)
    (inst shl result :cl)))


;;;; Static functions.

(define-static-function two-arg-/ (x y) :translate /)

(define-static-function two-arg-gcd (x y) :translate gcd)
(define-static-function two-arg-lcm (x y) :translate lcm)

(define-static-function two-arg-and (x y) :translate logand)
(define-static-function two-arg-ior (x y) :translate logior)
(define-static-function two-arg-xor (x y) :translate logxor)


;;; Support for the Mersenne Twister, MT19937, random number generator
;;; due to Matsumoto and Nishimura.
;;;
;;; Makoto Matsumoto and T. Nishimura, "Mersenne twister: A
;;; 623-dimensionally equidistributed uniform pseudorandom number
;;; generator.", ACM Transactions on Modeling and Computer Simulation,
;;; 1997, to appear.
;;;
;;; State:
;;;  0-1:   Constant matrix A. [0, #x9908b0df] (not used here)
;;;  2:     Index; init. to 1.
;;;  3-626: State.
;;;
(defknown random-mt19937 ((simple-array (unsigned-byte 32) (*)))
  (unsigned-byte 32) ())
;;;
(define-vop (random-mt19937)
  (:policy :fast-safe)
  (:translate random-mt19937)
  (:args (state :scs (descriptor-reg) :to :result))
  (:arg-types simple-array-unsigned-byte-32)
  (:temporary (:sc unsigned-reg :from (:eval 0) :to :result) k)
  (:temporary (:sc unsigned-reg :offset eax-offset
		   :from (:eval 0) :to :result) tmp)
  (:results (y :scs (unsigned-reg) :from (:eval 0)))
  (:result-types unsigned-num)
  (:generator 50
    (inst mov k (make-ea :dword :base state
			 :disp (- (* (+ 2 vm:vector-data-offset) vm:word-bytes)
				  vm:other-pointer-type)))
    (inst cmp k 624)
    (inst jmp :ne no-update)
    (inst mov tmp state)	; The state is passed in EAX.
    (inst call (make-fixup 'random-mt19937-update :assembly-routine))
    ;; Restore k, and set to 0.
    (inst xor k k)
    NO-UPDATE
    ;; y = ptgfsr[k++];
    (inst mov y (make-ea :dword :base state :index k :scale 4
			 :disp (- (* (+ 3 vm:vector-data-offset) vm:word-bytes)
				  vm:other-pointer-type)))
    ;; y ^= (y >> 11);
    (inst shr y 11)
    (inst xor y (make-ea :dword :base state :index k :scale 4
			 :disp (- (* (+ 3 vm:vector-data-offset) vm:word-bytes)
				  vm:other-pointer-type)))
    ;; y ^= (y << 7) & #x9d2c5680
    (inst mov tmp y)
    (inst inc k)
    (inst shl tmp 7)
    (inst mov (make-ea :dword :base state
		       :disp (- (* (+ 2 vm:vector-data-offset) vm:word-bytes)
				vm:other-pointer-type))
	  k)
    (inst and tmp #x9d2c5680)
    (inst xor y tmp)
    ;; y ^= (y << 15) & #xefc60000
    (inst mov tmp y)
    (inst shl tmp 15)
    (inst and tmp #xefc60000)
    (inst xor y tmp)
    ;; y ^= (y >> 18);
    (inst mov tmp y)
    (inst shr tmp 18)
    (inst xor y tmp)))

;;; Modular arithmetic
;;; logical operations
#+modular-arith
(progn
(c::define-modular-fun lognot-mod32 (x) lognot 32)
(define-vop (lognot-mod32/unsigned=>unsigned)
  (:translate lognot-mod32)
  (:args (x :scs (unsigned-reg unsigned-stack) :target r
	    :load-if (not (and (sc-is x unsigned-stack)
			       (sc-is r unsigned-stack)
			       (location= x r)))))
  (:arg-types unsigned-num)
  (:results (r :scs (unsigned-reg)
	       :load-if (not (and (sc-is x unsigned-stack)
				  (sc-is r unsigned-stack)
				  (location= x r)))))
  (:result-types unsigned-num)
  (:policy :fast-safe)
  (:generator 1
    (move r x)
    (inst not r)))

(define-vop (lognot-mod32/signed=>unsigned lognot-mod32/unsigned=>unsigned)
  (:translate lognot-mod32)
  (:args (x :scs (signed-reg signed-stack)
	    :load-if (not (and (sc-is x signed-stack)
			       (sc-is r unsigned-stack)))))
  (:arg-types signed-num))

;; Handle (ldb (byte 32 0) (- x)).  The (- x) gets converted to
;; (%negate x), so we build modular functions for %negate.

(c::define-modular-fun %negate-mod32 (x) kernel:%negate 32)

(define-vop (%negate-mod32/unsigned=>unsigned)
  (:translate %negate-mod32)
  (:args (x :scs (unsigned-reg)))
  (:arg-types unsigned-num)
  (:results (res :scs (unsigned-reg)))
  (:result-types unsigned-num)
  (:policy :fast-safe)
  (:generator 2
    (move res x)	      
    (inst neg res)))

(define-vop (%negate-mod32/signed=>unsigned)
  (:translate %negate-mod32)
  (:args (x :scs (signed-reg)))
  (:arg-types signed-num)
  (:results (res :scs (unsigned-reg)))
  (:result-types unsigned-num)
  (:policy :fast-safe)
  (:generator 2
    (move res x)
    (inst neg res)))

(macrolet
    ((frob (op)
       (let ((name (symbolicate "FAST-" op "/SIGNED=>UNSIGNED"))
	     (vop (symbolicate "FAST-" op "/SIGNED=>SIGNED"))
	     (trans (symbolicate op "-MOD32")))
	 `(progn
	    (defknown ,trans ((signed-byte 32) (signed-byte 32))
	      (unsigned-byte 32)
	      (movable foldable flushable))
	    (define-vop (,name ,vop)
	    (:translate ,trans)
	    (:results (r :scs (unsigned-reg)))
	    (:result-types unsigned-num))))))
  (frob +)
  (frob -)
  (frob logxor)
  (frob *))

(defmacro define-modular-backend (fun &optional constantp derived)
  (let ((mfun-name (symbolicate fun '-mod32))
	(modvop (symbolicate 'fast- fun '-mod32/unsigned=>unsigned))
	(modcvop (symbolicate 'fast- fun '-mod32-c/unsigned=>unsigned))
	(vop (symbolicate 'fast- (or derived fun) '/unsigned=>unsigned))
	(cvop (symbolicate 'fast- (or derived fun) '-c/unsigned=>unsigned))
	(smodvop (symbolicate 'fast- (or derived fun) '-mod32/signed=>unsigned))
	(svop (symbolicate 'fast- (or derived fun) '/signed=>unsigned)))
    `(progn
       (c::define-modular-fun ,mfun-name (x y) ,fun 32)
       (define-vop (,modvop ,vop)
	 (:translate ,mfun-name))
       ,@(when constantp
	       `((define-vop (,modcvop ,cvop)
		   (:translate ,mfun-name))))
       (define-vop (,smodvop ,svop)
	 (:translate ,mfun-name)))))

(define-modular-backend + t)
(define-modular-backend - t)
(define-modular-backend logxor t)
(define-modular-backend *)

(c::def-source-transform logeqv (&rest args)
  (if (oddp (length args))
      `(logxor ,@args)
      `(lognot (logxor ,@args))))
(c::def-source-transform logandc1 (x y)
  `(logand (lognot ,x) ,y))
(c::def-source-transform logandc2 (x y)
  `(logand ,x (lognot ,y)))
(c::def-source-transform logorc1 (x y)
  `(logior (lognot ,x) ,y))
(c::def-source-transform logorc2 (x y)
  `(logior ,x (lognot ,y)))
(c::def-source-transform lognor (x y)
  `(lognot (logior ,x ,y)))
(c::def-source-transform lognand (x y)
  `(lognot (logand ,x ,y)))

(defknown vm::ash-left-mod32 (integer (integer 0))
  (unsigned-byte 32)
  (foldable flushable movable))

(define-vop (fast-ash-left-mod32-c/unsigned=>unsigned
             fast-ash-c/unsigned=>unsigned)
  (:translate ash-left-mod32))

)

(in-package :C)
#+modular-arith
(progn
(define-modular-fun-optimizer ash ((integer count) :width width)
  ;; The count needs to be (unsigned-byte 32) because the Sparc shift
  ;; instruction takes the count modulo 32.  (NOTE: Should we make
  ;; this work on Ultrasparcs?  We could then use the sllx instruction
  ;; which takes the count mod 64.  Then a left shift of 32 or more
  ;; will produce 0 in the lower 32 bits of the register, which is
  ;; what we want.)
  (when (and (<= width 32)
	     (csubtypep (continuation-type count)
			(specifier-type '(unsigned-byte 5))))
    (cut-to-width integer width)
    'vm::ash-left-mod32))
)
