#| -*-Scheme-*-

$Id: rulflo.scm,v 1.6 2003/02/14 18:28:06 cph Exp $

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|#

;;;; LAP Generation Rules: Flonum rules

(declare (usual-integrations))

(define (flonum-source! register)
  (float-register->fpr (load-alias-register! register 'FLOAT)))

(define (flonum-target! pseudo-register)
  (delete-dead-registers!)
  (float-register->fpr (allocate-alias-register! pseudo-register 'FLOAT)))

(define (flonum-temporary!)
  (float-register->fpr (allocate-temporary-register! 'FLOAT)))

(define-rule statement
  ;; convert a floating-point number to a flonum object
  (ASSIGN (REGISTER (? target))
	  (FLOAT->OBJECT (REGISTER (? source))))
  (let ((source (fpr->float-register (flonum-source! source))))
    (let ((target (standard-target! target)))
      (LAP
       ; (SW 0 (OFFSET 0 ,regnum:free))	; make heap parsable forwards
       (ORI ,regnum:free ,regnum:free #b100) ; Align to odd quad byte
       ,@(deposit-type-address (ucode-type flonum) regnum:free target)
       ,@(with-values
	     (lambda ()
	       (immediate->register
		(make-non-pointer-literal (ucode-type manifest-nm-vector) 2)))
	   (lambda (prefix alias)
	     (LAP ,@prefix
		  (SW ,alias (OFFSET 0 ,regnum:free)))))
       ,@(fp-store-doubleword 4 regnum:free source)
       (ADDI ,regnum:free ,regnum:free 12)))))

(define-rule statement
  ;; convert a flonum object to a floating-point number
  (ASSIGN (REGISTER (? target)) (OBJECT->FLOAT (REGISTER (? source))))
  (let ((source (standard-move-to-temporary! source)))
    (let ((target (fpr->float-register (flonum-target! target))))
      (LAP ,@(object->address source source)
	   ,@(fp-load-doubleword 4 source target #T)))))

;;;; Flonum Arithmetic

(define-rule statement
  (ASSIGN (REGISTER (? target))
	  (FLONUM-1-ARG (? operation) (REGISTER (? source)) (? overflow?)))
  overflow?				;ignore
  (let ((source (flonum-source! source)))
    ((flonum-1-arg/operator operation) (flonum-target! target) source)))

(define (flonum-1-arg/operator operation)
  (lookup-arithmetic-method operation flonum-methods/1-arg))

(define flonum-methods/1-arg
  (list 'FLONUM-METHODS/1-ARG))

;;; Notice the weird ,', syntax here.
;;; If LAP changes, this may also have to change.

(let-syntax
    ((define-flonum-operation
       (sc-macro-transformer
	(lambda (form environment)
	  environment
	  `(DEFINE-ARITHMETIC-METHOD ',(cadr form) FLONUM-METHODS/1-ARG
	     (LAMBDA (TARGET SOURCE)
	       (LAP (,(caddr form) ,',TARGET ,',SOURCE))))))))
  (define-flonum-operation flonum-abs ABS.D)
  (define-flonum-operation flonum-negate NEG.D))

(define-rule statement
  (ASSIGN (REGISTER (? target))
	  (FLONUM-2-ARGS (? operation)
			 (REGISTER (? source1))
			 (REGISTER (? source2))
			 (? overflow?)))
  overflow?				;ignore
  (let ((source1 (flonum-source! source1))
	(source2 (flonum-source! source2)))
    ((flonum-2-args/operator operation) (flonum-target! target)
					source1
					source2)))

(define (flonum-2-args/operator operation)
  (lookup-arithmetic-method operation flonum-methods/2-args))

(define flonum-methods/2-args
  (list 'FLONUM-METHODS/2-ARGS))

(let-syntax
    ((define-flonum-operation
       (sc-macro-transformer
	(lambda (form environment)
	  environment
	  `(DEFINE-ARITHMETIC-METHOD ',(cadr form) FLONUM-METHODS/2-ARGS
	     (LAMBDA (TARGET SOURCE1 SOURCE2)
	       (LAP (,(caddr form) ,',TARGET ,',SOURCE1 ,',SOURCE2))))))))
  (define-flonum-operation flonum-add ADD.D)
  (define-flonum-operation flonum-subtract SUB.D)
  (define-flonum-operation flonum-multiply MUL.D)
  (define-flonum-operation flonum-divide DIV.D))

;;;; Flonum Predicates

(define-rule predicate
  (FLONUM-PRED-1-ARG (? predicate) (REGISTER (? source)))
  ;; No immediate zeros, easy to generate by subtracting from itself
  (let ((temp (flonum-temporary!))
	(source (flonum-source! source)))
    (LAP (MTC1 0 ,temp)
	 (MTC1 0 ,(+ temp 1))
	 (NOP)
	 ,@(flonum-compare
	    (case predicate
	      ((FLONUM-ZERO?) 'C.EQ.D)
	      ((FLONUM-NEGATIVE?) 'C.LT.D)
	      ((FLONUM-POSITIVE?) 'C.GT.D)
	      (else (error "unknown flonum predicate" predicate)))
	    source temp))))

(define-rule predicate
  (FLONUM-PRED-2-ARGS (? predicate)
		      (REGISTER (? source1))
		      (REGISTER (? source2)))
  (flonum-compare (case predicate
		    ((FLONUM-EQUAL?) 'C.EQ.D)
		    ((FLONUM-LESS?) 'C.LT.D)
		    ((FLONUM-GREATER?) 'C.GT.D)
		    (else (error "unknown flonum predicate" predicate)))
		  (flonum-source! source1)
		  (flonum-source! source2)))

(define (flonum-compare cc r1 r2)
  (set-current-branches!
   (lambda (label)
     (LAP (BC1T (@PCR ,label)) (NOP)))
   (lambda (label)
     (LAP (BC1F (@PCR ,label)) (NOP))))
  (if (eq? cc 'C.GT.D)
      (LAP (C.LT.D ,r2 ,r1) (NOP))
      (LAP (,cc ,r1 ,r2) (NOP))))