crc32

.386
.model flat
option casemap :none
 
.data
    sum DWORD 0
    POLY DWORD 0EDB88320h
    reminder DWORD 0FFFFFFFFh
    crc32tbl dd 000000000h, 077073096h, 0ee0e612ch, 0990951bah 
        dd      0076dc419h, 0706af48fh, 0e963a535h, 09e6495a3h 
        dd      00edb8832h, 079dcb8a4h, 0e0d5e91eh, 097d2d988h 
        dd      009b64c2bh, 07eb17cbdh, 0e7b82d07h, 090bf1d91h 
        dd      01db71064h, 06ab020f2h, 0f3b97148h, 084be41deh 
        dd      01adad47dh, 06ddde4ebh, 0f4d4b551h, 083d385c7h 
        dd      0136c9856h, 0646ba8c0h, 0fd62f97ah, 08a65c9ech 
        dd      014015c4fh, 063066cd9h, 0fa0f3d63h, 08d080df5h 
        dd      03b6e20c8h, 04c69105eh, 0d56041e4h, 0a2677172h 
        dd      03c03e4d1h, 04b04d447h, 0d20d85fdh, 0a50ab56bh 
        dd      035b5a8fah, 042b2986ch, 0dbbbc9d6h, 0acbcf940h 
        dd      032d86ce3h, 045df5c75h, 0dcd60dcfh, 0abd13d59h 
        dd      026d930ach, 051de003ah, 0c8d75180h, 0bfd06116h 
        dd      021b4f4b5h, 056b3c423h, 0cfba9599h, 0b8bda50fh 
        dd      02802b89eh, 05f058808h, 0c60cd9b2h, 0b10be924h 
        dd      02f6f7c87h, 058684c11h, 0c1611dabh, 0b6662d3dh 
        dd      076dc4190h, 001db7106h, 098d220bch, 0efd5102ah 
        dd      071b18589h, 006b6b51fh, 09fbfe4a5h, 0e8b8d433h 
        dd      07807c9a2h, 00f00f934h, 09609a88eh, 0e10e9818h 
        dd      07f6a0dbbh, 0086d3d2dh, 091646c97h, 0e6635c01h 
        dd      06b6b51f4h, 01c6c6162h, 0856530d8h, 0f262004eh 
        dd      06c0695edh, 01b01a57bh, 08208f4c1h, 0f50fc457h 
        dd      065b0d9c6h, 012b7e950h, 08bbeb8eah, 0fcb9887ch 
        dd      062dd1ddfh, 015da2d49h, 08cd37cf3h, 0fbd44c65h 
        dd      04db26158h, 03ab551ceh, 0a3bc0074h, 0d4bb30e2h 
        dd      04adfa541h, 03dd895d7h, 0a4d1c46dh, 0d3d6f4fbh 
        dd      04369e96ah, 0346ed9fch, 0ad678846h, 0da60b8d0h 
        dd      044042d73h, 033031de5h, 0aa0a4c5fh, 0dd0d7cc9h 
        dd      05005713ch, 0270241aah, 0be0b1010h, 0c90c2086h 
        dd      05768b525h, 0206f85b3h, 0b966d409h, 0ce61e49fh 
        dd      05edef90eh, 029d9c998h, 0b0d09822h, 0c7d7a8b4h 
        dd      059b33d17h, 02eb40d81h, 0b7bd5c3bh, 0c0ba6cadh 
        dd      0edb88320h, 09abfb3b6h, 003b6e20ch, 074b1d29ah 
        dd      0ead54739h, 09dd277afh, 004db2615h, 073dc1683h 
        dd      0e3630b12h, 094643b84h, 00d6d6a3eh, 07a6a5aa8h 
        dd      0e40ecf0bh, 09309ff9dh, 00a00ae27h, 07d079eb1h 
        dd      0f00f9344h, 08708a3d2h, 01e01f268h, 06906c2feh 
        dd      0f762575dh, 0806567cbh, 0196c3671h, 06e6b06e7h 
        dd      0fed41b76h, 089d32be0h, 010da7a5ah, 067dd4acch 
        dd      0f9b9df6fh, 08ebeeff9h, 017b7be43h, 060b08ed5h 
        dd      0d6d6a3e8h, 0a1d1937eh, 038d8c2c4h, 04fdff252h 
        dd      0d1bb67f1h, 0a6bc5767h, 03fb506ddh, 048b2364bh 
        dd      0d80d2bdah, 0af0a1b4ch, 036034af6h, 041047a60h 
        dd      0df60efc3h, 0a867df55h, 0316e8eefh, 04669be79h 
        dd      0cb61b38ch, 0bc66831ah, 0256fd2a0h, 05268e236h 
        dd      0cc0c7795h, 0bb0b4703h, 0220216b9h, 05505262fh 
        dd      0c5ba3bbeh, 0b2bd0b28h, 02bb45a92h, 05cb36a04h 
        dd      0c2d7ffa7h, 0b5d0cf31h, 02cd99e8bh, 05bdeae1dh 
        dd      09b64c2b0h, 0ec63f226h, 0756aa39ch, 0026d930ah 
        dd      09c0906a9h, 0eb0e363fh, 072076785h, 005005713h 
        dd      095bf4a82h, 0e2b87a14h, 07bb12baeh, 00cb61b38h 
        dd      092d28e9bh, 0e5d5be0dh, 07cdcefb7h, 00bdbdf21h 
        dd      086d3d2d4h, 0f1d4e242h, 068ddb3f8h, 01fda836eh 
        dd      081be16cdh, 0f6b9265bh, 06fb077e1h, 018b74777h 
        dd      088085ae6h, 0ff0f6a70h, 066063bcah, 011010b5ch 
        dd      08f659effh, 0f862ae69h, 0616bffd3h, 0166ccf45h 
        dd      0a00ae278h, 0d70dd2eeh, 04e048354h, 03903b3c2h 
        dd      0a7672661h, 0d06016f7h, 04969474dh, 03e6e77dbh 
        dd      0aed16a4ah, 0d9d65adch, 040df0b66h, 037d83bf0h 
        dd      0a9bcae53h, 0debb9ec5h, 047b2cf7fh, 030b5ffe9h 
        dd      0bdbdf21ch, 0cabac28ah, 053b39330h, 024b4a3a6h 
        dd      0bad03605h, 0cdd70693h, 054de5729h, 023d967bfh 
        dd      0b3667a2eh, 0c4614ab8h, 05d681b02h, 02a6f2b94h 
        dd      0b40bbe37h, 0c30c8ea1h, 05a05df1bh, 02d02ef8dh 
 
.code
_crc32 PROC PUBLIC
    push ebp
    mov ebp, esp ; build stack frame
    ; variables in stack
    ; [ebp+12]  data length (the second argument)
    ; [ebp+8]	pointer to string data (the first argument)
    ; [ebp+4]	return address
    ; [ebp]	previous ebp
 
;************************************************************************
; begin CRC32 calculation												*
;************************************************************************				
	MOV EAX, -1
	MOV EBX, [ebp+8]
	OR EBX, EBX
	MOV ECX, [ebp+12]
	OR ECX, ECX
	JZ _Done
 
_NextByte:
	MOV DL, [EBX]
	XOR DL, AL
	MOVZX EDX, DL
	SHR EAX, 8
	XOR EAX, [crc32tbl + EDX*4]
	INC EBX
	LOOP _NextByte
 
_Done:
	NOT EAX 
;************************************************************************
; end CRC32 calculation													*
;************************************************************************
	leave
	ret
_crc32 ENDP
END ; file ends here