idouble.ppcs

;;; -*- Mode: LISP; Syntax: Common-Lisp; Package: ALPHA-AXP-INTERNALS; Base: 10; Lowercase: T -*-

;(include-header "aihead.s")
;(include-header "aistat.s")
;(include-header "ifunhead.s")

(comment "Support for double precision floating point.")

(define-subroutine |FetchDoubleFloat|
		   (arg2 arg5 arg6 t5 t6 t7 t8 t9 t10 t11 t12)
		   (r0)
  (using-multiple-memory-reads (t9 t10 t11 t12)
   (fetch-double-float-internal  arg2 arg5 arg6 t5 t6 t7 t8)
   ))

(define-subroutine |ConsDoubleFloat|
		   (arg2 arg5 arg6 t5 t6 t7 t8 t9 t10)
		   (r0)
  (clr R31)
  (cons-double-float-internal  arg5 arg6 R31 arg2 t5 t6 t7 t8 t9 t10))

(define-instruction |DoDoubleFloatOp| :operand-from-stack-immediate ()
    ;; The top four things are the stack are fixnums that represent the
    ;; two double-float quantities.  We don't bother to type-check them.
    (LWA arg3 -20 (iSP) "X high")
    (LWA arg4 -12 (iSP) "X low")
    (LWA arg5 -4 (iSP) "Y high")
    (LWA arg6  4 (iSP) "Y low")
    (sldi arg3 arg3 32 "Get high part up top")
    (clrldi arg4 arg4 32)
    (sldi arg5 arg5 32 "Get high part up top")
    (clrldi arg6 arg6 32)
    (OR arg3 arg3 arg4 "ARG3 is now X")
    (OR arg5 arg5 arg6 "ARG5 is now Y")
    (STD arg3 PROCESSORSTATE_FP0 (ivory))
    (STD arg5 PROCESSORSTATE_FP1 (ivory))
    (srdi t2 arg1 32 "Immediate tag")
    (clrldi t1 arg1 32 "Immediate data")
    (CheckDataType t2 |TypeFixnum| doublefloatiop t3)
    (LFD f1 PROCESSORSTATE_FP0 (ivory))
    (LFD f2 PROCESSORSTATE_FP1 (ivory))
    (floating-exception-checking-prelude)
    (register-dispatch t1  t2 t3
      (|DoubleFloatOpAdd|
	(FADD f1 f2 f1))
      (|DoubleFloatOpSub|
	(FSUB f1 f2 f1))
      (|DoubleFloatOpMultiply|
	(FMUL f1 f2 f1))
      (|DoubleFloatOpDivide|
	(FDIV f1 f2 f1)))
    (floating-exception-checking-postlude doublefloatexc t1)
    (get-nil t3 "There was no FP exception")
  (unlikely-label doublefloatmerge)
    (STFD f1 PROCESSORSTATE_FP0 (ivory))
    (LWA t1 PROCESSORSTATE_FP0+4 (ivory))
    (LWA t2 PROCESSORSTATE_FP0 (ivory))
    ;;+++ The next four lines should be made more efficient
    (ADDI iSP iSP -32 "Pop all the operands")
    (stack-push-fixnum t2 t4 "Push high result")
    (stack-push-fixnum t1 t4 "Push low result")
    (stack-push t3 t4 "Push the exception predicate")
    (ContinueToNextInstruction)
  (label doublefloatexc)
    ;; We don't signal a real exception because this gets used in Genera's
    ;; floating point exception handlers, and we don't want recursive lossage.
    (get-t t3 "Indicate an FP exception occurred")
    (B doublefloatmerge)
  (label doublefloatiop)
    (illegal-operand unknown-double-float-op))


(comment "Fin.")