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; file: modf_wmt.asm
; Copyright (C) 1985-2000 Intel Corporation.;; The information and source code contained herein is the exclusive property; of Intel Corporation and may not be disclosed, examined, or reproduced in; whole or in part without explicit written authorization from the Company.;; Implemented in VNIIEF-STL, july 2000
; double modf (double x, double *iptr); Returns the value of the signed fractional part of argument;; Willamette specific version (MASM 6.15 required);; Description:; The modf functions break the argument value into integral and fractional parts,; each of which has the same type and sign as the argument. They store the integral; part (in floating-point format) in the object pointed to by iptr.;; Special cases:; modf(NaN,iptr) = that NaN and stores that NaN in the *iptr object; modf(INF,iptr) = 0 at the sign of x and stores that INF in the *iptr object;; Accuracy:; The result is always exact.
.xlist include cruntime.inc.list
_FUNC_ equ <modf>_FUNC_DEF_ equ <_modf_default>_FUNC_P4_ equ <_modf_pentium4>_FUNC_DEF_EXTERN_ equ 1 include disp_pentium4.inc
EXTRN C __libm_error_support : NEAR
.const ALIGN 16
;-- 16x-aligned data --------------------------------------------------------
_Mantissa DQ 0000fffffffffffffH,0000fffffffffffffH_Bns DQ 00000000000000433H,00000000000000433H_Sign DQ 08000000000000000H,08000000000000000H_Zero DQ 00000000000000000H,00000000000000000H
codeseg ALIGN 16
; double modf (double x, double *iptr);
; Stack frame locations
modf_x TEXTEQU <esp+4>modf_iptr TEXTEQU <esp+12>modf_result TEXTEQU <modf_x>XMMWORD TEXTEQU <OWORD>
PUBLIC _modf_pentium4_modf_pentium4 PROC NEAR
movq xmm0, QWORD PTR [modf_x] ; x movapd xmm2, XMMWORD PTR _Bns ; movapd xmm3, xmm0 ; x movapd xmm1, xmm0 ; x movapd xmm4, xmm0 ; x movapd xmm6, xmm0 psllq xmm0, 1 ; exp(x) ; remove sign psrlq xmm0, 53 ; exp(x) ; exp(x) psrlq xmm3, 52 ; exp(x) ; sign(x) | exp(x) andpd xmm4, XMMWORD PTR _Sign ; sign(x) movd eax, xmm0 ; exp(x) psubd xmm2, xmm0 ; mov ecx, DWORD PTR [modf_iptr] ; iptr psrlq xmm1, xmm2 ; truncate psllq xmm1, xmm2 ; t = trunc(x) movd edx, xmm3 ; sign(x) | exp(x)
cmp eax, 03ffH ; if abs(x) < 1.0 jl SHORT ret_z ; case A cmp eax, 0432H ; if abs(x) >=2**53 jg SHORT ret_xm ; case B
movq QWORD PTR [ecx], xmm1 ; *iptr = t subsd xmm6, xmm1 orpd xmm6, xmm4 ; set sign if frac = 0.0
movq QWORD PTR [modf_result], xmm6 fld QWORD PTR [modf_result] ; return signed result ret ;
ret_z: ; case A: |x|<1.0
movq QWORD PTR [ecx], xmm4 ; *iptr = properly-signed 0.0 fld QWORD PTR [modf_x] ; return (X) ret ;
ret_xm: ; case B: exp(x) >= 53
cmp eax, 07ffH ; check Inf (NaN) movq xmm0, QWORD PTR [modf_x] ; x je SHORT ret_inf_nan ;
movq QWORD PTR [ecx], xmm0 ;
cmp edx, 800H ; fldz ; if x is positive, return 0.0 jl SHORT return ;
fchs ; if x is negative, return -0.0
return:
ret ;
ret_inf_nan:
movapd xmm1, xmm0 addsd xmm0, xmm0 movq QWORD PTR [ecx], xmm0 ; andpd xmm0, XMMWORD PTR _Mantissa ; cmppd xmm0, XMMWORD PTR _Zero, 4 ; Mask = (x == Inf) ? 0 : 1 pextrw eax, xmm0, 0 ; eax=(x==INF)? 0:1
andpd xmm0, xmm1 ; t = Mask & x orpd xmm0, xmm4 ; t |= Sign(x)
mov edx, 1007 cmp eax, 0 ; if NaN, call libm_error_support jnz CALL_LIBM_ERROR
movq QWORD PTR [modf_result], xmm0 ; fld QWORD PTR [modf_result] ; return (t) ret ;
CALL_LIBM_ERROR: ;call libm_error_support(void *arg1,void *arg2,void *retval,error_types input_tag) sub esp, 28 movlpd QWORD PTR [esp+16], xmm0 mov DWORD PTR [esp+12],edx mov edx, esp add edx,16 mov DWORD PTR [esp+8],edx add edx,16+8 mov DWORD PTR [esp+4],edx sub edx, 8 mov DWORD PTR [esp],edx call NEAR PTR __libm_error_support; movlpd xmm0, QWORD PTR [esp+16]
; movlpd QWORD PTR [esp+16], xmm0 ; return result fld QWORD PTR [esp+16] ; add esp,28 ret
_modf_pentium4 ENDP
END
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