;;; -*- 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: /home/pvaneynd/fakeroot/cvs2.cons.org/src/compiler/x86/sap.lisp,v 1.2 1997/02/08 22:09:34 dtc Exp $")
;;;
;;; **********************************************************************
;;;
;;; This file contains the x86 VM definition of SAP operations.
;;;
;;; Written by William Lott.
;;;
;;; Debugged by Paul F. Werkowski Spring/Summer 1995.
;;; Enhancements/debugging by Douglas T. Crosher 1996.
;;;
(in-package :x86)


;;;; Moves and coercions:

;;; Move a tagged SAP to an untagged representation.
;;;
(define-vop (move-to-sap)
  (:args (x :scs (descriptor-reg)))
  (:results (y :scs (sap-reg)))
  (:note "pointer to SAP coercion")
  (:generator 1
    (loadw y x sap-pointer-slot other-pointer-type)))
;;;
(define-move-vop move-to-sap :move
  (descriptor-reg) (sap-reg))

;;; Move an untagged SAP to a tagged representation.
;;;

(define-vop (move-from-sap)
  (:args (sap :scs (sap-reg) :to :save))
  (:temporary (:sc dword-reg) alloc)
  (:results (res :scs (descriptor-reg)))
  (:note "SAP to pointer coercion") 
  (:generator 20
    (with-fixed-allocation (res alloc sap-type sap-size)
      (storew sap res sap-pointer-slot other-pointer-type))))
	   
;;;
(define-move-vop move-from-sap :move
  (sap-reg) (descriptor-reg))


;;; Move untagged sap values.
;;;
(define-vop (sap-move)
  (:args (x :target y
	    :scs (sap-reg)
	    :load-if (not (location= x y))))
  (:results (y :scs (sap-reg)
	       :load-if (not (location= x y))))
  (:note "SAP move")
  (:effects)
  (:affected)
  (:generator 0
    (move y x)))


;;;
(define-move-vop sap-move :move
  (sap-reg) (sap-reg))


;;; Move untagged sap arguments/return-values.
;;;
(define-vop (move-sap-argument)
  (:args (x :target y
	    :scs (sap-reg))
	 (fp :scs (any-reg)
	     :load-if (not (sc-is y sap-reg))))
  (:results (y))
  (:note "SAP argument move")
  (:generator 0
    (sc-case y
      (sap-reg
       (move y x))
      (sap-stack
       (if (= (tn-offset fp) esp-offset)
	   (storew x fp (tn-offset y))	; c-call
	   (storew x fp (- (1+ (tn-offset y)))))))))
;;;
(define-move-vop move-sap-argument :move-argument
  (descriptor-reg sap-reg) (sap-reg))


;;; Use standard MOVE-ARGUMENT + coercion to move an untagged sap to a
;;; descriptor passing location.
;;;
(define-move-vop move-argument :move-argument
  (sap-reg) (descriptor-reg))



;;;; SAP-INT and INT-SAP

(define-vop (sap-int)
  (:args (sap :scs (sap-reg) :target int))
  (:arg-types system-area-pointer)
  (:results (int :scs (unsigned-reg)))
  (:result-types unsigned-num)
  (:translate sap-int)
  (:policy :fast-safe)
  (:generator 1
    (move int sap)))

(define-vop (int-sap)
  (:args (int :scs (unsigned-reg) :target sap))
  (:arg-types unsigned-num)
  (:results (sap :scs (sap-reg)))
  (:result-types system-area-pointer)
  (:translate int-sap)
  (:policy :fast-safe)
  (:generator 1
    (move sap int)))



;;;; POINTER+ and POINTER-

(define-vop (pointer+)
  (:translate sap+)
  (:args (ptr :scs (sap-reg) :target res)
	 (offset :scs (signed-reg)))
  (:arg-types system-area-pointer signed-num)
  (:results (res :scs (sap-reg) :from (:argument 0)))
  (:result-types system-area-pointer)
  (:policy :fast-safe)
  (:generator 1
    (move res ptr)
    (inst add res offset)))

(define-vop (pointer+-c)
  (:translate sap+)
  (:args (ptr :scs (sap-reg) :target res))
  (:info offset)
  (:arg-types system-area-pointer (:constant (signed-byte 32)))
  (:results (res :scs (sap-reg)))
  (:result-types system-area-pointer)
  (:policy :fast-safe)
  (:generator 1
    (move res ptr)
    (inst add res offset)))

(define-vop (pointer-)
  (:translate sap-)
  (:args (ptr1 :scs (sap-reg) :target res)
	 (ptr2 :scs (sap-reg)))
  (:arg-types system-area-pointer system-area-pointer)
  (:policy :fast-safe)
  (:results (res :scs (signed-reg) :from (:argument 0)))
  (:result-types signed-num)
  (:generator 1
    (move res ptr1)
    (inst sub res ptr2)))



;;;; mumble-SYSTEM-REF and mumble-SYSTEM-SET

(eval-when (compile eval)

(defmacro def-system-ref-and-set
	  (ref-name set-name sc type size &optional signed)
  (let ((ref-name-c (symbolicate ref-name "-C"))
	(set-name-c (symbolicate set-name "-C"))
	(temp-sc (symbolicate size "-REG")))
    `(progn
       (define-vop (,ref-name)
	 (:translate ,ref-name)
	 (:policy :fast-safe)
	 (:args (sap :scs (sap-reg))
		(offset :scs (signed-reg)))
	 (:arg-types system-area-pointer signed-num)
	 ,@(unless (eq size :dword)
	     `((:temporary (:sc ,temp-sc :from (:eval 0) :to (:eval 1))
			   temp)))
	 (:results (result :scs (,sc)))
	 (:result-types ,type)
	 (:generator 5
	   (inst mov ,(if (eq size :dword) 'result 'temp)
		 (make-ea ,size :base sap :index offset))
	   ,@(unless (eq size :dword)
	       `((inst ,(if signed 'movsx 'movzx)
		       result temp)))))
       (define-vop (,ref-name-c)
	 (:translate ,ref-name)
	 (:policy :fast-safe)
	 (:args (sap :scs (sap-reg)))
	 (:arg-types system-area-pointer (:constant (signed-byte 32)))
	 (:info offset)
	 ,@(unless (eq size :dword)
	     `((:temporary (:sc ,temp-sc :from (:eval 0) :to (:eval 1))
			   temp)))
	 (:results (result :scs (,sc)))
	 (:result-types ,type)
	 (:generator 4
	   (inst mov ,(if (eq size :dword) 'result 'temp)
		 (make-ea ,size :base sap :disp offset))
	   ,@(unless (eq size :dword)
	       `((inst ,(if signed 'movsx 'movzx)
		       result temp)))))
       (define-vop (,set-name)
	 (:translate ,set-name)
	 (:policy :fast-safe)
	 (:args (sap :scs (sap-reg) :to (:eval 0))
		(offset :scs (signed-reg) :to (:eval 0))
		(value :scs (,sc)
		       :target ,(if (eq size :dword) 'result 'temp)))
	 (:arg-types system-area-pointer signed-num ,type)
	 ,@(unless (eq size :dword)
	     `((:temporary (:sc ,temp-sc :offset eax-offset
				:from (:argument 2) :to (:result 0)
				:target result)
			   temp)))
	 (:results (result :scs (,sc)))
	 (:result-types ,type)
	 (:generator 5
	   ,@(unless (eq size :dword)
	       `((move eax-tn value)))
	   (inst mov (make-ea ,size :base sap :index offset)
		 ,(if (eq size :dword) 'value 'temp))
	   (move result ,(if (eq size :dword) 'value 'eax-tn))))
       (define-vop (,set-name-c)
	 (:translate ,set-name)
	 (:policy :fast-safe)
	 (:args (sap :scs (sap-reg) :to (:eval 0))
		(value :scs (,sc)
		       :target ,(if (eq size :dword) 'result 'temp)))
	 (:arg-types system-area-pointer (:constant (signed-byte 32)) ,type)
	 (:info offset)
	 ,@(unless (eq size :dword)
	     `((:temporary (:sc ,temp-sc :offset eax-offset
				:from (:argument 2) :to (:result 0)
				:target result)
			   temp)))
	 (:results (result :scs (,sc)))
	 (:result-types ,type)
	 (:generator 4
	   ,@(unless (eq size :dword)
	       `((move eax-tn value)))
	   (inst mov (make-ea ,size :base sap :disp offset)
		 ,(if (eq size :dword) 'value 'temp))
	   (move result ,(if (eq size :dword) 'value 'eax-tn)))))))

); eval-when (compile eval)

(def-system-ref-and-set sap-ref-8 %set-sap-ref-8
  unsigned-reg positive-fixnum :byte nil)
(def-system-ref-and-set signed-sap-ref-8 %set-signed-sap-ref-8
  signed-reg tagged-num :byte t)
(def-system-ref-and-set sap-ref-16 %set-sap-ref-16
  unsigned-reg positive-fixnum :word nil)
(def-system-ref-and-set signed-sap-ref-16 %set-signed-sap-ref-16
  signed-reg tagged-num :word t)
(def-system-ref-and-set sap-ref-32 %set-sap-ref-32
  unsigned-reg unsigned-num :dword nil)
(def-system-ref-and-set signed-sap-ref-32 %set-signed-sap-ref-32
  signed-reg signed-num :dword t)
(def-system-ref-and-set sap-ref-sap %set-sap-ref-sap
  sap-reg system-area-pointer :dword)


;;; Sap-Ref-Double
(define-vop (sap-ref-double)
  (:translate sap-ref-double)
  (:policy :fast-safe)
  (:args (sap :scs (sap-reg))
	 (offset :scs (signed-reg)))
  (:arg-types system-area-pointer signed-num)
  (:results (result :scs (double-reg)))
  (:result-types double-float)
  (:generator 5
     (with-empty-tn@fp-top(result)
        (inst fldd (make-ea :dword :base sap :index offset)))))

(define-vop (sap-ref-double-c)
  (:translate sap-ref-double)
  (:policy :fast-safe)
  (:args (sap :scs (sap-reg)))
  (:arg-types system-area-pointer (:constant (signed-byte 32)))
  (:info offset)
  (:results (result :scs (double-reg)))
  (:result-types double-float)
  (:generator 4
     (with-empty-tn@fp-top(result)
        (inst fldd (make-ea :dword :base sap :disp offset)))))

(define-vop (%set-sap-ref-double)
  (:translate %set-sap-ref-double)
  (:policy :fast-safe)
  (:args (sap :scs (sap-reg) :to (:eval 0))
	 (offset :scs (signed-reg) :to (:eval 0))
	 (value :scs (double-reg)))
  (:arg-types system-area-pointer signed-num double-float)
  (:results (result :scs (double-reg)))
  (:result-types double-float)
  (:generator 5
    (cond ((zerop (tn-offset value))
	   ;; Value is in ST0
	   (inst fstd (make-ea :dword :base sap :index offset))
	   (unless (zerop (tn-offset result))
		   ;; Value is in ST0 but not result.
		   (inst fstd result)))
	  (t
	   ;; Value is not in ST0.
	   (inst fxch value)
	   (inst fstd (make-ea :dword :base sap :index offset))
	   (cond ((zerop (tn-offset result))
		  ;; The result is in ST0.
		  (inst fstd value))
		 (t
		  ;; Neither value or result are in ST0
		  (unless (location= value result)
			  (inst fstd result))
		  (inst fxch value)))))))

(define-vop (%set-sap-ref-double-c)
  (:translate %set-sap-ref-double)
  (:policy :fast-safe)
  (:args (sap :scs (sap-reg) :to (:eval 0))
	 (value :scs (double-reg)))
  (:arg-types system-area-pointer (:constant (signed-byte 32)) double-float)
  (:info offset)
  (:results (result :scs (double-reg)))
  (:result-types double-float)
  (:generator 4
    (cond ((zerop (tn-offset value))
	   ;; Value is in ST0
	   (inst fstd (make-ea :dword :base sap :disp offset))
	   (unless (zerop (tn-offset result))
		   ;; Value is in ST0 but not result.
		   (inst fstd result)))
	  (t
	   ;; Value is not in ST0.
	   (inst fxch value)
	   (inst fstd (make-ea :dword :base sap :disp offset))
	   (cond ((zerop (tn-offset result))
		  ;; The result is in ST0.
		  (inst fstd value))
		 (t
		  ;; Neither value or result are in ST0
		  (unless (location= value result)
			  (inst fstd result))
		  (inst fxch value)))))))


;;; Sap-Ref-Single
(define-vop (sap-ref-single)
  (:translate sap-ref-single)
  (:policy :fast-safe)
  (:args (sap :scs (sap-reg))
	 (offset :scs (signed-reg)))
  (:arg-types system-area-pointer signed-num)
  (:results (result :scs (single-reg)))
  (:result-types single-float)
  (:generator 5
     (with-empty-tn@fp-top(result)
        (inst fld (make-ea :dword :base sap :index offset)))))

(define-vop (sap-ref-single-c)
  (:translate sap-ref-single)
  (:policy :fast-safe)
  (:args (sap :scs (sap-reg)))
  (:arg-types system-area-pointer (:constant (signed-byte 32)))
  (:info offset)
  (:results (result :scs (single-reg)))
  (:result-types single-float)
  (:generator 4
     (with-empty-tn@fp-top(result)
        (inst fld (make-ea :dword :base sap :disp offset)))))

(define-vop (%set-sap-ref-single)
  (:translate %set-sap-ref-single)
  (:policy :fast-safe)
  (:args (sap :scs (sap-reg) :to (:eval 0))
	 (offset :scs (signed-reg) :to (:eval 0))
	 (value :scs (single-reg)))
  (:arg-types system-area-pointer signed-num single-float)
  (:results (result :scs (single-reg)))
  (:result-types single-float)
  (:generator 5
    (cond ((zerop (tn-offset value))
	   ;; Value is in ST0
	   (inst fst (make-ea :dword :base sap :index offset))
	   (unless (zerop (tn-offset result))
		   ;; Value is in ST0 but not result.
		   (inst fst result)))
	  (t
	   ;; Value is not in ST0.
	   (inst fxch value)
	   (inst fst (make-ea :dword :base sap :index offset))
	   (cond ((zerop (tn-offset result))
		  ;; The result is in ST0.
		  (inst fst value))
		 (t
		  ;; Neither value or result are in ST0
		  (unless (location= value result)
			  (inst fst result))
		  (inst fxch value)))))))

(define-vop (%set-sap-ref-single-c)
  (:translate %set-sap-ref-single)
  (:policy :fast-safe)
  (:args (sap :scs (sap-reg) :to (:eval 0))
	 (value :scs (single-reg)))
  (:arg-types system-area-pointer (:constant (signed-byte 32)) single-float)
  (:info offset)
  (:results (result :scs (single-reg)))
  (:result-types single-float)
  (:generator 4
    (cond ((zerop (tn-offset value))
	   ;; Value is in ST0
	   (inst fst (make-ea :dword :base sap :disp offset))
	   (unless (zerop (tn-offset result))
		   ;; Value is in ST0 but not result.
		   (inst fst result)))
	  (t
	   ;; Value is not in ST0.
	   (inst fxch value)
	   (inst fst (make-ea :dword :base sap :disp offset))
	   (cond ((zerop (tn-offset result))
		  ;; The result is in ST0.
		  (inst fst value))
		 (t
		  ;; Neither value or result are in ST0
		  (unless (location= value result)
			  (inst fst result))
		  (inst fxch value)))))))


;;; Noise to convert normal lisp data objects into SAPs.

(define-vop (vector-sap)
  (:translate vector-sap)
  (:policy :fast-safe)
  (:args (vector :scs (descriptor-reg) :target sap))
  (:results (sap :scs (sap-reg)))
  (:result-types system-area-pointer)
  (:generator 2
    (move sap vector)
    (inst add sap (- (* vector-data-offset word-bytes) other-pointer-type))))

