Leaked source code of windows server 2003
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118 lines
3.6 KiB

;***
;
; Copyright (c) 1984-2001, Microsoft Corporation. All rights reserved.
;
;Purpose:
; support for sqrt() function
;
;Revision History:
;
;*******************************************************************************
.xlist
include cruntime.inc
include elem87.inc
.list
.data
extrn _indefinite:tbyte
extrn __fastflag:dword
_NAME_ db 'sqrt',0,0,0,0
CODESEG
extrn _startOneArgErrorHandling:near
extrn _fload_withFB:near
extrn _convertTOStoQNaN:near
extrn _checkTOS_withFB:near
extrn _math_exit:near
extrn _fast_exit:near
extrn _load_CW:near
; MUST BE MODIFIED
; arg ErrorType result
;-------------------------------------------
;QNaN DOMAIN_QNAN QNaN
;SNaN DOMAIN indefinite
;negative DOMAIN indefinite
;-infinity DOMAIN indefinite
;+infinity - infinity
;+0.0 - +0.0
;-0.0 - -0.0
;indefinite is like QNaN
;denormal fld converts it to normal (80 bits)
public sqrt,_CIsqrt
_CIsqrt proc
sub esp,DBLSIZE+4 ; for argument
fst qword ptr [esp]
call _checkTOS_withFB
call start
add esp,DBLSIZE+4
ret
sqrt label proc
lea edx,[esp+4]
call _fload_withFB
start:
push edx ; allocate space for Control Word
fstcw [esp] ; store Control Word
mov eax,[esp+0ch] ; eax contains high dword
; at this point we have on stack: cw(4), ret_addr(4), arg1(8bytes)
jz inf_or_nan
cmp word ptr[esp], default_CW
je CW_is_set_to_default
call _load_CW ; use user's precision bits
CW_is_set_to_default:
test eax,80000000h
jnz test_if_x_zero
x_is_denormal: ; denormal is like normal
fsqrt
exit:
cmp __fastflag,0
jnz _fast_exit
; prepare in registers arguments for math_exit
mov edx,OP_SQRT
lea ecx,[_NAME_]
jmp _math_exit
test_if_x_zero: ; x <= 0
test eax,7ff00000H
jnz negative_x
test eax,000fffffH
jnz negative_x ; denormal operand
cmp dword ptr[esp+8],0 ; test if low dword is zero
jnz negative_x ; denormal operand
jmp exit
not_infinity:
call _convertTOStoQNaN ; eax MUST contain high dword
jmp _Error_handling ; eax=error number
inf_or_nan:
test eax,000fffffh
jnz not_infinity
cmp dword ptr[esp+8],0 ; test if low dword is zero
jnz not_infinity
and eax,80000000H ; test sign of infinity
jz exit ; infinity is already in ST(0)
negative_x:
fstp st(0)
fld [_indefinite]
mov eax,DOMAIN
_Error_handling:
cmp __fastflag,0
jnz _fast_exit
mov edx,OP_SQRT
lea ecx,[_NAME_]
call _startOneArgErrorHandling
pop edx ; remove saved CW from stack
ret
_CIsqrt endp
end