I wrote a subroutine to calculate the CRC32 of a section of ROM/RAM. It can process a whole 512kB ROM in about 3 seconds. Not sure what anyone might use it for, it's just a fun mini-project I thought I'd share. https://github.com/cvghivebrain/CRC3268k Code (Text): ; --------------------------------------------------------------------------- ; Subroutine to calculate CRC32 of region of ROM/RAM ; input: ; a1 = start address ; d0.l = length of data ; output: ; d1.l = CRC32 ; uses d0.l, d2.l, a1, a2 ; usage: ; lea Address,a1 ; move.l #length,d0 ; bsr.w CalcCRC32 ; cmpi.l #expected_value,d1 ; bne.w Doesnt_match ; branch if CRC32 doesn't match ; --------------------------------------------------------------------------- CalcCRC32: moveq #-1,d1 ; initial value tst.l d0 ; check if size is valid bmi.s .exit ; branch if not beq.s .exit lea CRC32_Table(pc),a2 .loop: moveq #0,d2 move.b (a1)+,d2 ; get byte from source eor.b d1,d2 add.w d2,d2 add.w d2,d2 ; multiply by 4 lsr.l #8,d1 ; shift right 1 byte move.l (a2,d2.w),d2 eor.l d2,d1 ; eor with value from table subq.l #1,d0 ; subtract 1 from size bne.s .loop ; repeat if not 0 .exit: not.l d1 ; final result rts CRC32_Table: dc.l $00000000, $77073096, $EE0E612C, $990951BA dc.l $076DC419, $706AF48F, $E963A535, $9E6495A3 dc.l $0EDB8832, $79DCB8A4, $E0D5E91E, $97D2D988 dc.l $09B64C2B, $7EB17CBD, $E7B82D07, $90BF1D91 dc.l $1DB71064, $6AB020F2, $F3B97148, $84BE41DE dc.l $1ADAD47D, $6DDDE4EB, $F4D4B551, $83D385C7 dc.l $136C9856, $646BA8C0, $FD62F97A, $8A65C9EC dc.l $14015C4F, $63066CD9, $FA0F3D63, $8D080DF5 dc.l $3B6E20C8, $4C69105E, $D56041E4, $A2677172 dc.l $3C03E4D1, $4B04D447, $D20D85FD, $A50AB56B dc.l $35B5A8FA, $42B2986C, $DBBBC9D6, $ACBCF940 dc.l $32D86CE3, $45DF5C75, $DCD60DCF, $ABD13D59 dc.l $26D930AC, $51DE003A, $C8D75180, $BFD06116 dc.l $21B4F4B5, $56B3C423, $CFBA9599, $B8BDA50F dc.l $2802B89E, $5F058808, $C60CD9B2, $B10BE924 dc.l $2F6F7C87, $58684C11, $C1611DAB, $B6662D3D dc.l $76DC4190, $01DB7106, $98D220BC, $EFD5102A dc.l $71B18589, $06B6B51F, $9FBFE4A5, $E8B8D433 dc.l $7807C9A2, $0F00F934, $9609A88E, $E10E9818 dc.l $7F6A0DBB, $086D3D2D, $91646C97, $E6635C01 dc.l $6B6B51F4, $1C6C6162, $856530D8, $F262004E dc.l $6C0695ED, $1B01A57B, $8208F4C1, $F50FC457 dc.l $65B0D9C6, $12B7E950, $8BBEB8EA, $FCB9887C dc.l $62DD1DDF, $15DA2D49, $8CD37CF3, $FBD44C65 dc.l $4DB26158, $3AB551CE, $A3BC0074, $D4BB30E2 dc.l $4ADFA541, $3DD895D7, $A4D1C46D, $D3D6F4FB dc.l $4369E96A, $346ED9FC, $AD678846, $DA60B8D0 dc.l $44042D73, $33031DE5, $AA0A4C5F, $DD0D7CC9 dc.l $5005713C, $270241AA, $BE0B1010, $C90C2086 dc.l $5768B525, $206F85B3, $B966D409, $CE61E49F dc.l $5EDEF90E, $29D9C998, $B0D09822, $C7D7A8B4 dc.l $59B33D17, $2EB40D81, $B7BD5C3B, $C0BA6CAD dc.l $EDB88320, $9ABFB3B6, $03B6E20C, $74B1D29A dc.l $EAD54739, $9DD277AF, $04DB2615, $73DC1683 dc.l $E3630B12, $94643B84, $0D6D6A3E, $7A6A5AA8 dc.l $E40ECF0B, $9309FF9D, $0A00AE27, $7D079EB1 dc.l $F00F9344, $8708A3D2, $1E01F268, $6906C2FE dc.l $F762575D, $806567CB, $196C3671, $6E6B06E7 dc.l $FED41B76, $89D32BE0, $10DA7A5A, $67DD4ACC dc.l $F9B9DF6F, $8EBEEFF9, $17B7BE43, $60B08ED5 dc.l $D6D6A3E8, $A1D1937E, $38D8C2C4, $4FDFF252 dc.l $D1BB67F1, $A6BC5767, $3FB506DD, $48B2364B dc.l $D80D2BDA, $AF0A1B4C, $36034AF6, $41047A60 dc.l $DF60EFC3, $A867DF55, $316E8EEF, $4669BE79 dc.l $CB61B38C, $BC66831A, $256FD2A0, $5268E236 dc.l $CC0C7795, $BB0B4703, $220216B9, $5505262F dc.l $C5BA3BBE, $B2BD0B28, $2BB45A92, $5CB36A04 dc.l $C2D7FFA7, $B5D0CF31, $2CD99E8B, $5BDEAE1D dc.l $9B64C2B0, $EC63F226, $756AA39C, $026D930A dc.l $9C0906A9, $EB0E363F, $72076785, $05005713 dc.l $95BF4A82, $E2B87A14, $7BB12BAE, $0CB61B38 dc.l $92D28E9B, $E5D5BE0D, $7CDCEFB7, $0BDBDF21 dc.l $86D3D2D4, $F1D4E242, $68DDB3F8, $1FDA836E dc.l $81BE16CD, $F6B9265B, $6FB077E1, $18B74777 dc.l $88085AE6, $FF0F6A70, $66063BCA, $11010B5C dc.l $8F659EFF, $F862AE69, $616BFFD3, $166CCF45 dc.l $A00AE278, $D70DD2EE, $4E048354, $3903B3C2 dc.l $A7672661, $D06016F7, $4969474D, $3E6E77DB dc.l $AED16A4A, $D9D65ADC, $40DF0B66, $37D83BF0 dc.l $A9BCAE53, $DEBB9EC5, $47B2CF7F, $30B5FFE9 dc.l $BDBDF21C, $CABAC28A, $53B39330, $24B4A3A6 dc.l $BAD03605, $CDD70693, $54DE5729, $23D967BF dc.l $B3667A2E, $C4614AB8, $5D681B02, $2A6F2B94 dc.l $B40BBE37, $C30C8EA1, $5A05DF1B, $2D02EF8D
