sqrt32.asm

这是我本人编写的一个32位定点小数运算的函数库。对于没有浮点运算器的场合

		.386
		.MODEL		SMALL

		.CODE
		PUBLIC		_FixSqrt32

_FixSqrt32	PROC
; (long x,long y)

		push        ebp
		mov         ebp,esp
		push        ecx
		push        ebx
		push        esi
		push        edi

		mov         eax,dword ptr [ebp+8]	; x
		cdq
		xor         eax,edx
		sub         eax,edx
		mov         ebx,eax
		imul        eax
		mov         esi,eax
		mov         edi,edx

		mov         eax,dword ptr [ebp+0Ch]	; y
		cdq
		xor         eax,edx
		sub         eax,edx
		mov         ecx,eax
		imul        eax
		cmp         ebx,ecx
		jae         l3
		mov         ebx,ecx

l3:		add         esi,eax
		adc         edi,edx

		mov         eax,esi
		mov         edx,edi
		div         ebx
		add         ebx,eax
		shr         ebx,1

		mov         eax,esi
		mov         edx,edi
		div         ebx
		add         ebx,eax
		shr         ebx,1

		mov         eax,esi
		mov         edx,edi
		div         ebx
		add         ebx,eax
		shr         ebx,1
		mov         eax,ebx

		pop         edi
		pop         esi
		pop         ebx
		mov         esp,ebp
		pop         ebp
		ret
_FixSqrt32	ENDP

		END