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