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Assembly Source File  |  1994-07-30  |  4KB  |  111 lines
  1. **
  2. **    termCRC.asm
  3. **
  4. **    CRC 32 bit checksum calculation routines
  5. **
  6. **    Written by Ralf Thanner, Georg Hörmann & Olaf `Olsen' Barthel
  7. **
  8. **    Copyright © 1990-1994 by Olaf `Olsen' Barthel
  9. **        All Rights Reserved
  10. **
  11.  
  12.     csect    text,0,0,1,2
  13.  
  14.     xdef    _DoCRC
  15.  
  16. _DoCRC:    movem.l    d2/d3,-(sp)    ; Save registers
  17.  
  18.     move.l    d0,d3        ; Save the length
  19.     lea    Table(pc),a1    ; Get the CRC table
  20.  
  21.     moveq    #-1,d0        ; Reset CRC value
  22.     moveq    #8,d2        ; Store for shifting
  23.  
  24. 1$    moveq    #0,d1        ; Avoid ext.w and ext.l
  25.     move.b    (a0)+,d1    ; Get the next data byte
  26.  
  27.     eor.b    d0,d1        ; Data = Data ^ CRC
  28.  
  29.     add.w    d1,d1
  30.     add.w    d1,d1        ; Turn byte index into long word index
  31.  
  32.     move.l    0(a1,d1.w),d1    ; Get table entry
  33.  
  34.     lsr.l    d2,d0        ; CRC = CRC >> 8
  35.     eor.l    d1,d0        ; CRC = Entry ^ CRC
  36.  
  37.     subq.l    #1,d3        ; Get next data byte
  38.     bne.b    1$
  39.  
  40.     movem.l    (sp)+,d2/d3    ; Restore registers
  41.     rts
  42.  
  43.     cnop    0,4
  44.  
  45. Table:    dc.l    $00000000,$77073096,$EE0E612C,$990951BA
  46.     dc.l    $076DC419,$706AF48F,$E963A535,$9E6495A3
  47.     dc.l    $0EDB8832,$79DCB8A4,$E0D5E91E,$97D2D988
  48.     dc.l    $09B64C2B,$7EB17CBD,$E7B82D07,$90BF1D91
  49.     dc.l    $1DB71064,$6AB020F2,$F3B97148,$84BE41DE
  50.     dc.l    $1ADAD47D,$6DDDE4EB,$F4D4B551,$83D385C7
  51.     dc.l    $136C9856,$646BA8C0,$FD62F97A,$8A65C9EC
  52.     dc.l    $14015C4F,$63066CD9,$FA0F3D63,$8D080DF5
  53.     dc.l    $3B6E20C8,$4C69105E,$D56041E4,$A2677172
  54.     dc.l    $3C03E4D1,$4B04D447,$D20D85FD,$A50AB56B
  55.     dc.l    $35B5A8FA,$42B2986C,$DBBBC9D6,$ACBCF940
  56.     dc.l    $32D86CE3,$45DF5C75,$DCD60DCF,$ABD13D59
  57.     dc.l    $26D930AC,$51DE003A,$C8D75180,$BFD06116
  58.     dc.l    $21B4F4B5,$56B3C423,$CFBA9599,$B8BDA50F
  59.     dc.l    $2802B89E,$5F058808,$C60CD9B2,$B10BE924
  60.     dc.l    $2F6F7C87,$58684C11,$C1611DAB,$B6662D3D
  61.     dc.l    $76DC4190,$01DB7106,$98D220BC,$EFD5102A
  62.     dc.l    $71B18589,$06B6B51F,$9FBFE4A5,$E8B8D433
  63.     dc.l    $7807C9A2,$0F00F934,$9609A88E,$E10E9818
  64.     dc.l    $7F6A0DBB,$086D3D2D,$91646C97,$E6635C01
  65.     dc.l    $6B6B51F4,$1C6C6162,$856530D8,$F262004E
  66.     dc.l    $6C0695ED,$1B01A57B,$8208F4C1,$F50FC457
  67.     dc.l    $65B0D9C6,$12B7E950,$8BBEB8EA,$FCB9887C
  68.     dc.l    $62DD1DDF,$15DA2D49,$8CD37CF3,$FBD44C65
  69.     dc.l    $4DB26158,$3AB551CE,$A3BC0074,$D4BB30E2
  70.     dc.l    $4ADFA541,$3DD895D7,$A4D1C46D,$D3D6F4FB
  71.     dc.l    $4369E96A,$346ED9FC,$AD678846,$DA60B8D0
  72.     dc.l    $44042D73,$33031DE5,$AA0A4C5F,$DD0D7CC9
  73.     dc.l    $5005713C,$270241AA,$BE0B1010,$C90C2086
  74.     dc.l    $5768B525,$206F85B3,$B966D409,$CE61E49F
  75.     dc.l    $5EDEF90E,$29D9C998,$B0D09822,$C7D7A8B4
  76.     dc.l    $59B33D17,$2EB40D81,$B7BD5C3B,$C0BA6CAD
  77.     dc.l    $EDB88320,$9ABFB3B6,$03B6E20C,$74B1D29A
  78.     dc.l    $EAD54739,$9DD277AF,$04DB2615,$73DC1683
  79.     dc.l    $E3630B12,$94643B84,$0D6D6A3E,$7A6A5AA8
  80.     dc.l    $E40ECF0B,$9309FF9D,$0A00AE27,$7D079EB1
  81.     dc.l    $F00F9344,$8708A3D2,$1E01F268,$6906C2FE
  82.     dc.l    $F762575D,$806567CB,$196C3671,$6E6B06E7
  83.     dc.l    $FED41B76,$89D32BE0,$10DA7A5A,$67DD4ACC
  84.     dc.l    $F9B9DF6F,$8EBEEFF9,$17B7BE43,$60B08ED5
  85.     dc.l    $D6D6A3E8,$A1D1937E,$38D8C2C4,$4FDFF252
  86.     dc.l    $D1BB67F1,$A6BC5767,$3FB506DD,$48B2364B
  87.     dc.l    $D80D2BDA,$AF0A1B4C,$36034AF6,$41047A60
  88.     dc.l    $DF60EFC3,$A867DF55,$316E8EEF,$4669BE79
  89.     dc.l    $CB61B38C,$BC66831A,$256FD2A0,$5268E236
  90.     dc.l    $CC0C7795,$BB0B4703,$220216B9,$5505262F
  91.     dc.l    $C5BA3BBE,$B2BD0B28,$2BB45A92,$5CB36A04
  92.     dc.l    $C2D7FFA7,$B5D0CF31,$2CD99E8B,$5BDEAE1D
  93.     dc.l    $9B64C2B0,$EC63F226,$756AA39C,$026D930A
  94.     dc.l    $9C0906A9,$EB0E363F,$72076785,$05005713
  95.     dc.l    $95BF4A82,$E2B87A14,$7BB12BAE,$0CB61B38
  96.     dc.l    $92D28E9B,$E5D5BE0D,$7CDCEFB7,$0BDBDF21
  97.     dc.l    $86D3D2D4,$F1D4E242,$68DDB3F8,$1FDA836E
  98.     dc.l    $81BE16CD,$F6B9265B,$6FB077E1,$18B74777
  99.     dc.l    $88085AE6,$FF0F6A70,$66063BCA,$11010B5C
  100.     dc.l    $8F659EFF,$F862AE69,$616BFFD3,$166CCF45
  101.     dc.l    $A00AE278,$D70DD2EE,$4E048354,$3903B3C2
  102.     dc.l    $A7672661,$D06016F7,$4969474D,$3E6E77DB
  103.     dc.l    $AED16A4A,$D9D65ADC,$40DF0B66,$37D83BF0
  104.     dc.l    $A9BCAE53,$DEBB9EC5,$47B2CF7F,$30B5FFE9
  105.     dc.l    $BDBDF21C,$CABAC28A,$53B39330,$24B4A3A6
  106.     dc.l    $BAD03605,$CDD70693,$54DE5729,$23D967BF
  107.     dc.l    $B3667A2E,$C4614AB8,$5D681B02,$2A6F2B94
  108.     dc.l    $B40BBE37,$C30C8EA1,$5A05DF1B,$2D02EF8D
  109.  
  110.     end
  111.