mcrt0.s

Version 6 Unix 核心源代码 Version 6 Unix 核心源代码

/ C runtime startoff including monitoring

cbufs	= 150.

.globl	_monitor
.globl	_sbrk
.globl	_main
.globl	_exit
.globl	_etext
.comm	countbase,2

.comm	savr5,2

start:
	setd
	mov	sp,r0
	mov	(r0),-(sp)
	tst	(r0)+
	mov	r0,2(sp)

	mov	$_etext,r1
	sub	$eprol,r1
	add	$7,r1
	ash	$-3,r1
	bic	$!17777,r1
	mov	$cbufs,-(sp)
	add	$3*[cbufs+1],r1
	mov	r1,-(sp)
	asl	r1
	mov	r1,-(sp)
	jsr	pc,_sbrk
	tst	(sp)+
	cmp	r0,$-1
	beq	9f
	mov	r0,-(sp)
	add	$6,r0
	mov	r0,countbase
	mov	$_etext,-(sp)
	mov	$eprol,-(sp)
	jsr	pc,_monitor
	add	$10.,sp
	jsr	pc,_main
	cmp	(sp)+,(sp)+
	jsr	pc,_exit

9:
	mov	$2,r0
	sys	write; 8f; 9f-8f

.data; 8: <No space for monitor buffer\n>; 9:.even; .text

_exit:
	mov	r5,-(sp)
	mov	sp,r5
	clr	-(sp)
	jsr	pc,_monitor
	tst	(sp)+
	mov	4(r5),r0
	sys	exit
eprol: