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;***;; Copyright (c) 1984-2001, Microsoft Corporation. All rights reserved.;; Revision History:; 01-26-01 PML Pentium4 merge.; 02-25-01 PML Fix pow(+/-0,-denorm);;*******************************************************************************
.xlist include cruntime.inc include elem87.inc.list
_FUNC_ equ <pow>_FUNC_DEF_ equ <_pow_default>_FUNC_P4_ equ <_pow_pentium4>_FUNC_P4_EXTERN_ equ 1 include disp_pentium4.inc
_FUNC_ equ <_CIpow>_FUNC_DEF_ equ <_CIpow_default>_FUNC_P4_ equ <_CIpow_pentium4> include disp_pentium4.inc
.dataglobalQ _half, 03fe0000000000000RPOW_name db 'pow',0
extrn _infinity:tbyteextrn _indefinite:tbyteextrn __fastflag:dword
CODESEG
extrn _startTwoArgErrorHandling:nearextrn _fload_withFB:nearextrn _convertTOStoQNaN:nearextrn _checkTOS_withFB:nearextrn _check_range_exit:nearextrn _fast_exit:nearextrn _load_CW:nearextrn _powhlp:nearextrn _twoToTOS:near
; arg1(base) arg2(exponent) ErrorType result;-----------------------------------------------------------;infinity not NaN called powhlp();not NaN infinity called powhlp();QNaN not SNaN DOMAIN_QNAN QNaN;SNaN any DOMAIN ;;*0 *0 - 1;*0 positive,not odd - +0;+0 positive, odd - +0;-0 positive, odd - -0;*0 negative,not odd SING infinity;+0 negative, odd SING infinity;-0 negative, odd SING -infinity;negative non-integer DOMAIN indefinite;indefinite is like QNaN;denormal(53) fld converts it to normal (64 bits);; * in table above stands for both + and -;; if exponent field of result is 0, error type is set to UNDERFLOW; if result is infinity, error type is set to OVERFLOW
public _CIpow_default,_pow_default_CIpow_default proc sub esp,2*DBLSIZE+4 ; prepare place for argument fxch st(1) fstp qword ptr [esp] ; base fst qword ptr [esp+8] ; exponent mov eax,[esp+12] ; high dword of exponent call start add esp,2*DBLSIZE+4 ; clean stack ret
_pow_default label proc
lea edx,[esp+12] ; load exponent(arg2) call _fload_withFBstart: mov ecx,eax ; make copy of eax push eax ; allocate space for Control Word fstcw [esp] ; store Control Word cmp word ptr[esp],default_CW je CW_is_set_to_default call _load_CW ; edx is destroyedCW_is_set_to_default:; at this point we have on stack: cw(4), ret_addr(4), arg1(8bytes), arg2(8bytes) and ecx,7ff00000H lea edx,[esp+8] ; edx points to arg1(base)
cmp ecx,7ff00000H je special_exponent
call _fload_withFB ; edx already initialized jz special_base test eax,7ff00000H jz test_if_we_have_zero_basebase_is_not_zero: mov cl,[esp+15] ; cl will contain sign and cl,80H ; test sign of base jnz test_if_exp_is_intnormal: ; denormal is like normal fyl2x ; compute y*log2(x) call _twoToTOS cmp cl,1 ; power was odd and base<0 ? jnz exit fchs ; if yes, we should change signexit: cmp __fastflag,0 jnz _fast_exit
; prepare in registers arguments for math_exit lea ecx,[POW_name] mov edx,OP_POW jmp _check_range_exit
_ErrorHandling: cmp __fastflag,0 jnz _fast_exit
lea ecx,[POW_name] mov edx,OP_POW call _startTwoArgErrorHandling pop edx ; remove saved CW from stack ret
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; some special cases;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; 1.One of arguments is NaNexponent_is_NAN: lea edx,[esp+8] ; pointer to arg1(base) call _fload_withFB ; load arg1 to FPU stack test byte ptr[esp+22],08H ; test if arg2(exponent) is SNaN jnz SNaN_detected inc ecx ; ecx!=0 when one of args is QNaN jmp test_base
SNaN_detected: fadd mov eax,DOMAIN jmp _ErrorHandling
base_is_NAN: test byte ptr[esp+14],08H ; is it SNaN jnz SNaN_detectedone_of_args_is_QNaN: fadd ; one of args is QNaN, and second is not SNaN mov eax,DOMAIN_QNAN jmp _ErrorHandling
special_base:; both arguments are loaded to FPU stack xor ecx,ecx jmp test_base
special_exponent:; only one argument is loaded to FPU stack xor ecx,ecx ; we use ecx to set flags and eax,000fffffH ; eax=high or eax,[esp+16] ; test whether mantissa is zero jne exponent_is_NAN lea edx,[esp+8] ; pointer to arg1(base) call _fload_withFB ; load arg1(base) to FPU stacktest_base: ; arg2 may be inf, QNaN or normal; both arguments are loaded to FPU stack mov eax,[esp+12] ; arg1 high mov edx,eax and eax,7ff00000H and edx,000fffffH ; test mantissa of arg2 cmp eax,7ff00000H jne end_of_tests or edx,[esp+8] jnz base_is_NAN ; arg1 is NaN,
end_of_tests: test ecx,ecx jnz one_of_args_is_QNaN ; base is QNaN
; one of args is infinity and second is not NaN. In this case we use powhlp();_usepowhlp sub esp, SBUFSIZE+8 ; get storage for _retval and savebuf mov ecx, esp push ecx ; push address for result
sub esp, 16 fstp qword ptr [esp] fstp qword ptr [esp+8]
fsave [ecx+8] call _powhlp add esp, 16 ; clear arguments if _cdecl. pop ecx frstor [ecx+8] fld qword ptr [ecx] ; load result on the NDP stack add esp, SBUFSIZE+8 ; get rid of storage
test eax,eax jz _fast_exit mov eax,DOMAIN jmp _ErrorHandling
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; 2. Base has zero exponent field;test_if_we_have_zero_base: mov eax,[esp+12] and eax,000fffffH or eax,[esp+8] jnz base_is_not_zero
; at this point we have two arguments on FPU stack.; We know that TOS is zero, and arg2 is not special.; We disinguish 3 cases:; (1) exponent is zero; (2) exponent is odd; (3) none of above
fstp st(0) ; remove zero from FPU stack mov eax,[esp+20] ; test if arg2 is also zero and eax,7fffffffh or eax,[esp+16] jz zero_to_zero; check whether exponent is odd call _test_whether_TOS_is_int; cl=1 if exponent is odd, 2 - if even and 0 otherwise mov ch,[esp+15] shr ch,7 ; ch==1 iff base is negative test [esp+23],80H ; check sign of exponent jz exp_is_positive; exponent is negative fld [_infinity] test cl,ch jz ret_inf fchs ; base <0 and exponent is negative oddret_inf: mov eax,SING jmp _ErrorHandling
exp_is_positive: ; eax=error_code fldz test cl,ch jz _fast_exit fchs ; base <0 and exponent positive is odd jmp _fast_exit ; return -0.0
zero_to_zero: ; arg1 and arg2 are zero fstp st(0) ; remove useless argument from FPU stack fld1 jmp _fast_exit
;;;;;;;;;;;;;;;;;;;;;;;;;;;;3. Base is negative.;; If exponent is not integer it's a DOMAIN error;
test_if_exp_is_int: fld st(1) call _test_whether_TOS_is_int fchs test cl,cl jnz normal fstp st(0) fstp st(0) fld [_indefinite] mov eax,DOMAIN jmp _ErrorHandling
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; _test_whether_TOS_is_int;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; returns in cl : 0,1,2 if TOS is non-int, odd int or even int respectively;_test_whether_TOS_is_int: fld st(0) ; duplicate stack top frndint fcomp ; is TOS integer??? mov cl,0 ; prepare return value fstsw ax sahf jne _not_int ; TOS is not integer fmul [_half] inc cl ; cl>0, when exponent is integer fld st(0) ; (exponent/2) frndint fcompp ; check if (exponent/2)==(int)(exponent/2) fstsw ax sahf jne _odd inc cl ; sign that exponent is even_odd: ret
_not_int: fstp st(0) ret_CIpow_default endp end
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