windows-nt/Source/XPSP1/NT/base/crts/fpw32/tran/i386/atan.asm

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2020-09-26 03:20:57 -05:00
;***
;
; Copyright (c) 1984-2001, Microsoft Corporation. All rights reserved.
;
;Purpose:
; support for atan() function
;
;Revision History:
; 01-26-01 PML Pentium4 merge.
;
;*******************************************************************************
.xlist
include cruntime.inc
include elem87.inc
.list
_FUNC_ equ <atan>
_FUNC_DEF_ equ <_atan_default>
_FUNC_P4_ equ <_atan_pentium4>
_FUNC_P4_EXTERN_ equ 1
include disp_pentium4.inc
_FUNC_ equ <_CIatan>
_FUNC_DEF_ equ <_CIatan_default>
_FUNC_P4_ equ <_CIatan_pentium4>
include disp_pentium4.inc
.data
_NAME_ db 'atan',0,0,0,0
extrn _indefinite:tbyte
extrn __fastflag:dword
extrn _piby2:tbyte
extrn _DEFAULT_CW_in_mem:word
CODESEG
extrn _startOneArgErrorHandling:near
extrn _fload_withFB:near
extrn _convertTOStoQNaN:near
extrn _checkTOS_withFB:near
extrn _math_exit:near
extrn _fast_exit:near
; arg ErrorType result
;-------------------------------------------
;+infinity - pi/2
;-infinity - -pi/2
;QNaN DOMAIN_QNAN QNaN | ? to distinguish them???
;SNaN DOMAIN indefinite | ? it costs 14 bytes per function
;indefinite is like QNaN
;denormal fld converts it to normal (80 bits)
public _atan_default,_CIatan_default
_CIatan_default proc
sub esp,DBLSIZE+4 ; for argument
fst qword ptr [esp]
call _checkTOS_withFB
call start
add esp, DBLSIZE+4
ret
_atan_default label proc
lea edx, [esp+4]
call _fload_withFB
start:
push edx ; allocate space for Control Word
fstcw [esp] ; store Control Word
; 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
; fpatan is not affected by precision bits. So we may ignore user's CW
fldcw _DEFAULT_CW_in_mem
CW_is_set_to_default:
fld1 ; load 1.0
fpatan ; fpatan(x,1.0)
exit:
cmp __fastflag, 0
jnz _fast_exit
; prepare in registers arguments for math_exit
mov edx,OP_ATAN
lea ecx,[_NAME_]
jmp _math_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
jne not_infinity
fstp st(0)
fld [_piby2]
test eax,80000000H
jz exit ; return pi/2
fchs
jmp exit ; return -pi/2
mov eax,DOMAIN
_Error_handling:
cmp __fastflag, 0
jnz _fast_exit
mov edx,OP_ATAN
lea ecx,[_NAME_]
call _startOneArgErrorHandling
pop edx ; remove saved CW from stack
ret
_CIatan_default endp
end