cc65/libsrc/cbm610/cgetc.s

;
; Ullrich von Bassewitz, 06.08.1998
;
; char cgetc (void);
;

	.export	   	_cgetc
	.import	   	plot, write_crtc
	.import	   	cursor

        .import         keyidx: zp, keybuf: zp, config: zp



_cgetc:	lda    	keyidx 	        ; Get number of characters
	bne	L2    	  	; Jump if there are already chars waiting

; Switch on the cursor if needed

       	lda	cursor
       	beq	L1    	    	; Jump if no cursor

       	jsr	plot  		; Set the current cursor position
       	ldy	#10
       	lda	config 	       	; Cursor format
       	jsr	write_crtc	; Set the cursor formar

L1:    	lda	keyidx
       	beq	L1

       	ldy	#10
       	lda	#$20  		; Cursor off
       	jsr	write_crtc

L2:    	ldx    	#$00  		; Get index
       	ldy	keybuf		; Get first character in the buffer
       	sei
L3:    	lda	keybuf+1,x	; Move up the remaining chars
       	sta	keybuf,x
       	inx
       	cpx	keyidx
       	bne	L3
       	dec	keyidx
       	cli

       	ldx	#$00  		; High byte
       	tya	      		; First char from buffer
       	rts