xref: /openbsd-src/lib/libc/arch/arm/sys/tfork_thread.S (revision c6f64c6fd2f950c7ce17d31c283f1cb710580942)
1/* $OpenBSD: tfork_thread.S,v 1.1 2012/03/22 00:44:55 guenther Exp $ */
2/*
3 * Copyright (c) 2005 Dale Rahn <drahn@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17#include <sys/syscall.h>
18#include <machine/asm.h>
19#include "SYS.h"
20
21/*
22 *                r0     r1          r2         r3
23 * __tfork_thread(param, stack_addr, start_fnc, start_arg);
24 */
25
26ENTRY(__tfork_thread)
27	stmdb   sp!, {r4}
28	mov	r4, r1
29
30
31	SYSTRAP(__tfork)
32	bcs	1f
33
34	/* check if we are parent or child */
35	cmp	r0, #0
36	ldmneia   sp!, {r4}
37	movne	pc, lr
38
39	/* child */
40	mov	sp, r4
41	mov	r0, r3
42	mov	lr, pc
43	mov	pc, r2
44	nop
45	SYSTRAP(__threxit)
461:
47	ldmia   sp!, {r4}
48	b     PIC_SYM(CERROR, PLT)
49