flat assembler
Message board for the users of flat assembler.
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bzt
Here's how I do it (CRC-32 with Castagnoli polynom and pre-calculated lookup table):
Code: ; --- CRC-32c --- ; IN: esi = buffer, ecx = length ; OUT: edx = crc crc32_calc: xor edx, edx xor eax, eax xor ebx, ebx .next: lodsb mov bl, dl xor bl, al mov eax, edx shr edx, 8 xor edx, dword [crclkp+4*ebx] dec ecx jnz .next ret crclkp: dd 000000000h, 0F26B8303h, 0E13B70F7h, 01350F3F4h, 0C79A971Fh, 035F1141Ch, 026A1E7E8h, 0D4CA64EBh dd 08AD958CFh, 078B2DBCCh, 06BE22838h, 09989AB3Bh, 04D43CFD0h, 0BF284CD3h, 0AC78BF27h, 05E133C24h dd 0105EC76Fh, 0E235446Ch, 0F165B798h, 0030E349Bh, 0D7C45070h, 025AFD373h, 036FF2087h, 0C494A384h dd 09A879FA0h, 068EC1CA3h, 07BBCEF57h, 089D76C54h, 05D1D08BFh, 0AF768BBCh, 0BC267848h, 04E4DFB4Bh dd 020BD8EDEh, 0D2D60DDDh, 0C186FE29h, 033ED7D2Ah, 0E72719C1h, 0154C9AC2h, 0061C6936h, 0F477EA35h dd 0AA64D611h, 0580F5512h, 04B5FA6E6h, 0B93425E5h, 06DFE410Eh, 09F95C20Dh, 08CC531F9h, 07EAEB2FAh dd 030E349B1h, 0C288CAB2h, 0D1D83946h, 023B3BA45h, 0F779DEAEh, 005125DADh, 01642AE59h, 0E4292D5Ah dd 0BA3A117Eh, 04851927Dh, 05B016189h, 0A96AE28Ah, 07DA08661h, 08FCB0562h, 09C9BF696h, 06EF07595h dd 0417B1DBCh, 0B3109EBFh, 0A0406D4Bh, 0522BEE48h, 086E18AA3h, 0748A09A0h, 067DAFA54h, 095B17957h dd 0CBA24573h, 039C9C670h, 02A993584h, 0D8F2B687h, 00C38D26Ch, 0FE53516Fh, 0ED03A29Bh, 01F682198h dd 05125DAD3h, 0A34E59D0h, 0B01EAA24h, 042752927h, 096BF4DCCh, 064D4CECFh, 077843D3Bh, 085EFBE38h dd 0DBFC821Ch, 02997011Fh, 03AC7F2EBh, 0C8AC71E8h, 01C661503h, 0EE0D9600h, 0FD5D65F4h, 00F36E6F7h dd 061C69362h, 093AD1061h, 080FDE395h, 072966096h, 0A65C047Dh, 05437877Eh, 04767748Ah, 0B50CF789h dd 0EB1FCBADh, 0197448AEh, 00A24BB5Ah, 0F84F3859h, 02C855CB2h, 0DEEEDFB1h, 0CDBE2C45h, 03FD5AF46h dd 07198540Dh, 083F3D70Eh, 090A324FAh, 062C8A7F9h, 0B602C312h, 044694011h, 05739B3E5h, 0A55230E6h dd 0FB410CC2h, 0092A8FC1h, 01A7A7C35h, 0E811FF36h, 03CDB9BDDh, 0CEB018DEh, 0DDE0EB2Ah, 02F8B6829h dd 082F63B78h, 0709DB87Bh, 063CD4B8Fh, 091A6C88Ch, 0456CAC67h, 0B7072F64h, 0A457DC90h, 0563C5F93h dd 0082F63B7h, 0FA44E0B4h, 0E9141340h, 01B7F9043h, 0CFB5F4A8h, 03DDE77ABh, 02E8E845Fh, 0DCE5075Ch dd 092A8FC17h, 060C37F14h, 073938CE0h, 081F80FE3h, 055326B08h, 0A759E80Bh, 0B4091BFFh, 0466298FCh dd 01871A4D8h, 0EA1A27DBh, 0F94AD42Fh, 00B21572Ch, 0DFEB33C7h, 02D80B0C4h, 03ED04330h, 0CCBBC033h dd 0A24BB5A6h, 0502036A5h, 04370C551h, 0B11B4652h, 065D122B9h, 097BAA1BAh, 084EA524Eh, 07681D14Dh dd 02892ED69h, 0DAF96E6Ah, 0C9A99D9Eh, 03BC21E9Dh, 0EF087A76h, 01D63F975h, 00E330A81h, 0FC588982h dd 0B21572C9h, 0407EF1CAh, 0532E023Eh, 0A145813Dh, 0758FE5D6h, 087E466D5h, 094B49521h, 066DF1622h dd 038CC2A06h, 0CAA7A905h, 0D9F75AF1h, 02B9CD9F2h, 0FF56BD19h, 00D3D3E1Ah, 01E6DCDEEh, 0EC064EEDh dd 0C38D26C4h, 031E6A5C7h, 022B65633h, 0D0DDD530h, 00417B1DBh, 0F67C32D8h, 0E52CC12Ch, 01747422Fh dd 049547E0Bh, 0BB3FFD08h, 0A86F0EFCh, 05A048DFFh, 08ECEE914h, 07CA56A17h, 06FF599E3h, 09D9E1AE0h dd 0D3D3E1ABh, 021B862A8h, 032E8915Ch, 0C083125Fh, 0144976B4h, 0E622F5B7h, 0F5720643h, 007198540h dd 0590AB964h, 0AB613A67h, 0B831C993h, 04A5A4A90h, 09E902E7Bh, 06CFBAD78h, 07FAB5E8Ch, 08DC0DD8Fh dd 0E330A81Ah, 0115B2B19h, 0020BD8EDh, 0F0605BEEh, 024AA3F05h, 0D6C1BC06h, 0C5914FF2h, 037FACCF1h dd 069E9F0D5h, 09B8273D6h, 088D28022h, 07AB90321h, 0AE7367CAh, 05C18E4C9h, 04F48173Dh, 0BD23943Eh dd 0F36E6F75h, 00105EC76h, 012551F82h, 0E03E9C81h, 034F4F86Ah, 0C69F7B69h, 0D5CF889Dh, 027A40B9Eh dd 079B737BAh, 08BDCB4B9h, 0988C474Dh, 06AE7C44Eh, 0BE2DA0A5h, 04C4623A6h, 05F16D052h, 0AD7D5351h Note: this is the CRC that might have hardware implementation on Intel CPUs. Used mostly in networking. For the "standard" CRC, also called ANSI CRC (used by GPT, png and gzip for example) you'll have to XOR the checksum before and after the loop with 0FFFFFFFFh and the lookup table is different of course. Cheers, bzt |
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