V6/usr/source/s5/putchr.s

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/ C library -- putchar

	.globl	_putchar,_flush
	.globl	_fout

_putchar:
	mov	r5,-(sp)
	mov	sp,r5
	mov	_fout+4,r0
	bne	1f
	jsr	pc,fl
	mov	_fout+4,r0
1:
	movb	4(r5),(r0)+
	beq	1f
	inc	_fout+4
	dec	_fout+2
	bgt	1f
	jsr	pc,fl
1:
	mov	4(r5),r0
	mov	(sp)+,r5
	rts	pc

_flush:
	mov	r5,-(sp)
	mov	sp,r5
	jsr	pc,fl
	mov	(sp)+,r5
	rts	pc

fl:
	mov	_fout+4,r0
	beq	1f
	sub	$_fout+6,r0
	mov	r0,0f
	mov	_fout,r0
	bne	2f
	inc	r0
2:
	sys	0; 9f
.data
9:	sys	write; _fout+6; 0:..
.text
1:
	mov	$_fout+6,_fout+4
	mov	$512.,_fout+2
	cmp	_fout,$2
	bhi	1f
	mov	$1,_fout+2
1:
	rts	pc

.bss
_fout:	.=.+518.