x86 Hash Algorithm

hash.asm

int Hash(char *str)
{
    char *p = str;

    __asm {
        mov ecx, dword ptr [esp+4]
        test ecx, 3
        je go
bloop:
        mov al, byte ptr[ecx]
        inc ecx
        test al,al
        je two
        test ecx, 3
        jne bloop
        add eax, 0
go:
        mov eax, dword ptr[ecx]
        mov edx, 7EFEFEFFh
        add edx, eax
        xor eax,0FFFFFFFFh
        xor eax, edx
        add ecx, 4
        test eax, 81010100h
        je go
        mov eax, dword ptr[ecx-4]
        test al, al
        je three
        test ah, ah
        je four
        test eax, 0FF0000h
        je ad
        test eax, 0FF000000h
        je two
        jmp go
two:
        lea eax, [ecx-1]
        mov ecx, dword ptr [p+4]
        sub eax, ecx
        ret
ad:
        lea eax, [ecx-2]
        mov ecx, dword ptr [p+4]
        sub eax, ecx
        ret
four:
        lea eax, [ecx-3]
        mov ecx, dword ptr [p+4]
        sub eax, ecx
        ret
three:
        lea eax, [ecx-4]
        mov ecx, dword ptr [p+4]
        sub eax, ecx
        ret
    }
}