**
**	termCRC.asm
**
**	CRC 32 bit checksum calculation routines
**
**	Written by Ralf Thanner, Georg Hörmann & Olaf `Olsen' Barthel
**
**	Copyright © 1990-1995 by Olaf `Olsen' Barthel
**		All Rights Reserved
**

	csect	text,0,0,1,2

	xdef	_DoCRC

_DoCRC:	movem.l	d2/d3,-(sp)	; Save registers

	move.l	d0,d3		; Save the length
	lea	Table(pc),a1	; Get the CRC table

	moveq	#-1,d0		; Reset CRC value
	moveq	#8,d2		; Store for shifting

1$	moveq	#0,d1		; Avoid ext.w and ext.l
	move.b	(a0)+,d1	; Get the next data byte

	eor.b	d0,d1		; Data = Data ^ CRC

	add.w	d1,d1
	add.w	d1,d1		; Turn byte index into long word index

	move.l	0(a1,d1.w),d1	; Get table entry

	lsr.l	d2,d0		; CRC = CRC >> 8
	eor.l	d1,d0		; CRC = Entry ^ CRC

	subq.l	#1,d3		; Get next data byte
	bne.b	1$

	movem.l	(sp)+,d2/d3	; Restore registers
	rts

	cnop	0,4

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

	end