# C library -- vfork

# pid = vfork();
#
# r1 == 0 in parent process, r1 == 1 in child process.
# r0 == pid of child in parent, r0 == pid of parent in child.
#
# trickery here, due to keith sklower, uses ret to clear the stack,
# and then returns with a jump indirect, since only one person can return
# with a ret off this stack... we do the ret before we vfork!
# 

	.set	vfork,66
.globl	_fork

_fork:
	.word	0x0000
	movl	16(fp),r2
	movab	here,16(fp)
	ret
here:
	chmk	$vfork
	tstl	r1		# child process ?
	bneq	child	# yes
	bcc 	parent		# if c-bit not set, fork ok
.globl	_errno
	movl	r0,_errno
	mnegl	$1,r0
	jmp	(r2)
child:
	clrl	r0
parent:
	jmp	(r2)