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; file: floor_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 floor (double x);; Willamette specific version (MASM 6.15 required);; Description:; The floor functions return the largest integer value not greater than x,; expressed as a (double-precision) floating-point number.;; Special cases:; floor(NaN) = that NaN; floor(INF) = that INF; floor(0) = that 0;; Accuracy:; The result is always exact.
.xlist include cruntime.inc.list
EXTRN C __libm_error_support : NEAR
_FUNC_ equ <floor>_FUNC_DEF_ equ <_floor_default>_FUNC_P4_ equ <_floor_pentium4>_FUNC_DEF_EXTERN_ equ 1 include disp_pentium4.inc
.const ALIGN 16
;-- 16x-aligned data --------------------------------------------------------
_One DQ 03ff0000000000000H,03ff0000000000000H_Bns DQ 00000000000000433H,00000000000000433H_NegOne DQ 0bff0000000000000H,04330000000000000H_NegZero DQ 08000000000000000H,08000000000000000H_S DQ 000000000000007ffH,00000000000000000H
codeseg ALIGN 16
; double floor (double x);
; Stack frame locations
floor_x TEXTEQU <esp+4>XMMWORD TEXTEQU <OWORD>
PUBLIC _floor_pentium4_floor_pentium4 PROC NEAR movq xmm0, QWORD PTR [floor_x] ; X movapd xmm2, XMMWORD PTR _Bns ; movapd xmm1, xmm0 ; movapd xmm7, xmm0 ; psrlq xmm0, 52 ; exp(x) ; sign(X) | exp(X) in XMM reg movd eax, xmm0 ; sign(X) | exp(X) in eax reg andpd xmm0, XMMWORD PTR _S ; exp(X) (+3ff) psubd xmm2, xmm0 ; exp(X) psrlq xmm1, xmm2 ; truncate the fraction (shift right)
test eax, 0800h ; jne SHORT negat ; if (X<0.0) goto negat cmp eax, 03ffh ;**** POSITIVE X ***** jl SHORT ret_zero ; if (X<1.0) return zero psllq xmm1, xmm2 ; truncate the fraction (integer part) cmp eax, 0432h ; if X is integer, return X jg SHORT return_x movq QWORD PTR [floor_x], xmm1 ; save integer part fld QWORD PTR [floor_x] ; return integer part ret ;
return_x:
ucomisd xmm7, xmm7 jnp not_nan
mov edx, 1005 ;call libm_error_support(void *arg1,void *arg2,void *retval,error_types input_tag) sub esp, 16 mov DWORD PTR [esp+12],edx mov edx, esp add edx, 16+4 mov DWORD PTR [esp+8],edx mov DWORD PTR [esp+4],edx mov DWORD PTR [esp],edx call NEAR PTR __libm_error_support add esp, 16
not_nan: fld QWORD PTR [floor_x] ; return integer part ret ;
negat: ; **** NEGATIVE X ****
movq xmm0, QWORD PTR [floor_x] ; psllq xmm1, xmm2 ; movapd xmm3, xmm0 ; cmppd xmm0, xmm1, 1 ; if X<integer part, form Mask
cmp eax, 0bffh ; if X > -1.0 return -1.0 jl SHORT ret_neg_one ; cmp eax, 0c32h ; if X is integer, return X jg SHORT return_x ;
andpd xmm0, XMMWORD PTR _One ; Mask & One subsd xmm1, xmm0 ; if X<integer part, movq QWORD PTR [floor_x], xmm1 ; return (int.part-1.0) fld QWORD PTR [floor_x] ; ret ;
ret_zero:
fldz ; ret ;
ret_neg_one:
cmppd xmm3, XMMWORD PTR _NegZero, 1 ; case for X = Negative Zero orpd xmm3, XMMWORD PTR _NegZero ; return X, if X == Negative Zero andpd xmm3, XMMWORD PTR _NegOne ; if X==NegZero, xmm3=0.0 movq QWORD PTR [floor_x], xmm3 ; fld QWORD PTR [floor_x] ; ret ;
_floor_pentium4 ENDP
END
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