title	PUSHBF
	subttl	Module from library C_4 : PUSHBF
	maclib	SYSEQU.LIB

; FILE:	PUSHBF.MAC
; DATE: 820819:1221
; MOD:	820820:1641	; Complete externals
; FOR:	Write A to pushback buf for channel C

; Push char back on specified channel
; ENTRY	: Accu contains char to push back
;	  Reg C contains channel number

	entry	pushbf

	ext	conbuf,fndbuf,cerror,moveu

pushbf:
	push	hl
	push	af
	ld	a,c		; Get channel
	and	00001111b	; .. check console
	jr	nz,pbf0
	ld	hl,conbuf	; OK, console is devic
	jr	pbf2
pbf0:
	call	fndbuf		; Check file mode
	inc	a
	jr	nz,pbf1
	call	cerror
	msg	<'PUSHBF: Pushback to output file'>
pbf1:
	ld	a,(hl)		; Get buffer
	inc	hl
	ld	h,(hl)
	ld	l,a
pbf2:
	ld	a,(hl)
	inc	(hl)
	cp	90
	jr	nc,full		; Check current count
	push	de
	push	bc
	ld	c,a
	ld	b,0
	inc	hl
	ld	d,h
	ld	e,l
	inc	de
	call	moveu		; .. make room
	pop	bc
	pop	de
	pop	af
	ld	(hl),a		; Insert character
	pop	hl
	ret
full:
	call	cerror
	msg	<'PUSHBF: Pushback buffer full'>

	end