/ u9 -- unix

trcv:
	jsr	r0,1f
	jsr	r0,1f
	jsr	r0,1f
	jsr	r0,1f
	jsr	r0,1f
	jsr	r0,1f
	jsr	r0,1f
	jsr	r0,1f
1:
	mov	r1,-(sp)
	mov	r2,-(sp)
	mov	r3,-(sp)
	mov	clockp,-(sp)
	mov	$s.syst+2,clockp
	sub	$trcv+4,r0 / 0%4 / calculate offset for tty causing
	asl	r0 / 0%8 / this interrupt
	mov	rcsr(r0),r2
	mov	rcbr(r0),r1
	tst	r2
	blt	1f / error
	tst	tty+6(r0)
	beq	1f
	bit	$40,r2 / parity
	bne	3f / branch if set
	tstb	tty+4(r0)
	blt	4f / 37 parity not allowed
	br	2f
3:
	bitb	$100,tty+4(r0)
	beq	2f / non-37 parity not allowed
4:
	bic	$!177,r1
	bit	$40,tty+4(r0)
	bne	3f / raw
	cmp	r1,$177
	beq	5f
	cmp	r1,$34
	bne	3f
5:
	mov	tty+6(r0),r0
	beq	2f
	movb	r1,6(r0) / interrupt or quit
	jsr	r0,wakeall
	br	2f
3:
	cmp	r1,$15 / or
	bne	3f
	bit	$20,tty+4(r0)
	beq	3f
	mov	$12,r1
3:
	bitb	$4,tty+4(r0)