lineget.src

	.page
	.subttl 'lineget subroutine

; linget  reads a line # from the current txtptr position
;	  and stores it in linnum  (valid range is 0-63999).
;
;	  on exit txtptr is pointing to the terminating char
;	  which is in .a with condition codes set.
;	  endchr will be =0 if no digit input, else >0. use it
;	  to distinguish between line # 0 & null input.

linget	ldx #0
	stx endchr	;flags line # input
	stx linnum	;init line # to 0
	stx linnum+1

1$	bcs 4$		;it's not a digit, do rts
	inc endchr	;indicate line # input
	sbc #$2f	;'0'-1 since c=0
	sta charac	;save for later
	lda linnum+1
	sta index
	cmp #25		;line number will be .lt. 64000?
	bcc 2$
	jmp snerr	;..no, syntax error.
2$	lda linnum
	asl a	    	;multiply by 10
	rol index
	asl a
	rol index
	adc linnum
	sta linnum
	lda index
	adc linnum+1
	sta linnum+1
	asl linnum
	rol linnum+1
	lda linnum
	adc charac	;add in digit
	sta linnum
	bcc 3$
	inc linnum+1
3$	jsr chrget
	jmp 1$

4$	rts
;end