swapcontext.S revision 1.10 
1/*	$NetBSD: swapcontext.S,v 1.10 2013/09/03 00:30:19 matt Exp $	*/
2
3/*-
4 * Copyright (c) 2001 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Klaus Klein.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include "SYS.h"
33#include "assym.h"
34
35#if defined(LIBC_SCCS) && !defined(lint)
36        RCSID("$NetBSD: swapcontext.S,v 1.10 2013/09/03 00:30:19 matt Exp $")
37#endif /* LIBC_SCCS && !lint */
38
39ENTRY(swapcontext)
40	.fnstart
41	.cfi_startproc
42	push	{r0-r2, lr}	/* Must save oucp, ucp, lr. */
43	.save	{r0-r2, lr}
44	.cfi_def_cfa_offset 16
45	.cfi_offset 14, -4
46	.cfi_offset 2, -8
47	.cfi_offset 1, -12
48	.cfi_offset 0, -16
49	bl	PIC_SYM(_C_LABEL(_getcontext), PLT)  /* getcontext(oucp) */
50	cmp	r0, #0
51#if !defined(__thumb__)
52	pop	{r0-r2, lr}
53	.cfi_def_cfa_offset 0
54	RETc(ne)
55#else
56	pop	{r0-r3}
57	beq	1f
58	.cfi_def_cfa_offset 0
59	.cfi_register 14, 3
60	RETr(r3)
611:
62#endif
63#if !defined(__thumb__)
64	str	sp, [r0, #_UC_REGS_SP]	/* Adjust saved SP. */
65	str	lr, [r0, #_UC_REGS_PC]	/* Adjust saved SP. */
66#else
67	mov	r2, sp
68	str	r2, [r0, #_UC_REGS_SP]	/* Adjust saved SP. */
69	str	r3, [r0, #_UC_REGS_PC]	/* Adjust saved PC. */
70	mov	lr, r3
71#endif
72#ifdef SOFTFLOAT
73	/* Ahem. */
74#endif
75	mov	r0, r1
76#if !defined(__thumb__) || defined(_ARM_ARCH_T2)
77	b	PIC_SYM(_C_LABEL(setcontext), PLT)
78#else
79	push	{lr}
80	bl	PIC_SYM(_C_LABEL(setcontext), PLT)
81	pop	{pc}
82#endif
83	.cfi_endproc
84	.fnend
85END(swapcontext)
86