sbrk.S revision 1.11 
1/*	$OpenBSD: sbrk.S,v 1.11 2023/12/10 16:45:51 deraadt Exp $ */
2/*-
3 * Copyright (c) 1991, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Ralph Campbell.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include "SYS.h"
35
36	.globl	__curbrk
37	.hidden	__curbrk
38
39	.data
40__curbrk:	PTR_VAL	_end
41	.size	__curbrk, . - __curbrk
42	.type	__curbrk,@object
43	.text
44
45FRAMESZ= MKFSIZ(1,1)
46GPOFF= FRAMESZ-2*REGSZ
47
48LEAF(sbrk, FRAMESZ)
49	PTR_SUBU sp, FRAMESZ
50	SETUP_GP64(GPOFF, sbrk)
51	.set	reorder
52	PTR_L	v1, __curbrk
53	li	v0, SYS_break
54	PTR_ADDU a0, a0, v1	# compute current break
5599:	syscall
56	PINSYSCALL(SYS_break, 99b)
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, CERROR
66	RESTORE_GP64
67	PTR_ADDU sp, FRAMESZ
68	jr	t9
69END(sbrk)
70	.weak	sbrk
71