sbrk.S revision 1.3 
1/*-
2 * Copyright (c) 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Ralph Campbell.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include "SYS.h"
34
35#if defined(SYSLIBC_SCCS)
36	.text
37	.asciz "$OpenBSD: sbrk.S,v 1.3 2004/09/09 16:14:02 pefo Exp $"
38#endif /* SYSLIBC_SCCS */
39
40	.globl	curbrk
41
42	.data
43curbrk:	PTR_VAL	_C_LABEL(end)
44	.text
45
46FRAMESZ= MKFSIZ(1,1)
47GPOFF= FRAMESZ-2*REGSZ
48
49LEAF(sbrk, FRAMESZ)
50	PTR_SUBU sp, FRAMESZ
51	SETUP_GP64(GPOFF, sbrk)
52	.set	reorder
53	PTR_L	v1, curbrk
54	li	v0, SYS_break
55	PTR_ADDU a0, a0, v1	# compute current break
56	syscall
57
58	bne	a3, zero, 1f
59	move	v0, v1		# return old val of curbrk from above
60	PTR_S	a0, curbrk	# save current val of curbrk from above
61	RESTORE_GP64
62	PTR_ADDU sp, FRAMESZ
63	j	ra
641:
65	LA	t9, _C_LABEL(cerror)
66	RESTORE_GP64
67	PTR_ADDU sp, FRAMESZ
68	jr	t9
69END(sbrk)
70