;----------------------------------------------------------------
; This is a module in the PL/I-80 utility library
;
; This module do all the 16 bit crc math
;
; CLRCRC	Clear the current crc -> call clrcrc();
; GETCRC	return the CRC        -> crc = getcrc(); /* bit(16) */
; ADDCRC	Add a byte to the crc -> call addcrc(option);
; MEMCRC	Add memory to the crc -> call memcrc(addr(mem),size);

;	Written By     Richard Holmes  09-12-84
;	Last update    Richard Holmes  09-12-84
;----------------------------------------------------------------
;
	name	'crc'
	public	getcrc,clrcrc,addcrc,memcrc
	extrn	getp2,getp1
;
getcrc:
	lhld	crc
	mov	a,l
	ret
clrcrc:
	lxi	h,0
	shld	crc
;
addcrc:
	call	getp1			; fetch the byte
;
addit:

	ret
;
memcrc:	; p1 -> memory, p2 = size
	call	getp2			; DE -> string
	mov	c,m
	inx	h
	mov	b,m			; BC = size
	mov	a,b
	ora	c
	rz
;
mem$loop:
	ldax	d
	push	b
	push	d
	call	addit
	pop	d
	pop	b			; save and restore all
	dcx	b
	mov	a,b
	ora	c
	jnz	mem$loop
	ret
;
	dseg
crc:	db	00,00
	end