brk.S revision 1.2 
1/*	$OpenBSD: brk.S,v 1.2 2001/09/24 13:20:26 art Exp $	*/
2/*	$NetBSD: brk.S,v 1.9 2000/07/25 20:15:40 mycroft Exp $	*/
3
4/*
5 * Copyright (c) 1992, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This software was developed by the Computer Systems Engineering group
9 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
10 * contributed to Berkeley.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 *    notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice, this list of conditions and the following disclaimer in the
19 *    documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 *    must display the following acknowledgement:
22 *	This product includes software developed by the University of
23 *	California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 *    may be used to endorse or promote products derived from this software
26 *    without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 */
40
41#include <machine/asm.h>
42
43#include "SYS.h"
44
45	.globl	_C_LABEL(__curbrk)
46	.globl	_C_LABEL(minbrk)
47	.globl	_C_LABEL(_end)
48
49#ifdef WEAK_ALIAS
50WEAK_ALIAS(brk, _brk)
51#endif
52
53	.data
54	.align	8
55_C_LABEL(minbrk):
56	.xword	_C_LABEL(_end)		/* lower brk limit; also for gmon code */
57	.text
58
59ENTRY(_brk)
60#ifdef PIC
61	PIC_PROLOGUE(%o5,%o4)
62	set	_C_LABEL(minbrk), %o4
63	ldx	[%o5 + %o4], %o4
64	ldx	[%o4], %o1		/* %o1 = minbrk */
65	cmp	%o1, %o0		/* if (minbrk > %o0) */
66	movg	%xcc, %o1, %o0		/*	%o0 = minbrk */
67	mov	%o0, %o2		/* save argument to syscall */
68	mov	SYS_break, %g1
69	t	ST_SYSCALL
70	set	_C_LABEL(__curbrk), %o3
71	bcc,a,pt	%icc, 1f
72	 ldx	[%o5 + %o3], %o4
73	ERROR()
741:
75	retl				/* success, return 0 & record new break */
76	 stx	%o2, [%o4]
77#else
78	sethi	%hi(_C_LABEL(minbrk)), %o1	/* %o1 = minbrk */
79	ldx	[%o1 + %lo(_C_LABEL(minbrk))], %o1
80	cmp	%o1, %o0		/* if (minbrk > %o0) */
81	movg	%xcc, %o1, %o0		/*	%o0 = minbrk */
82	mov	%o0, %o2		/* save argument to syscall */
83	mov	SYS_break, %g1
84	t	ST_SYSCALL
85	bcc,a,pt	%icc,1f
86	 sethi	%hi(_C_LABEL(__curbrk)), %g1
87	ERROR()
881:
89	retl				/* success, return 0 & record new break */
90	 stx	%o2, [%g1 + %lo(_C_LABEL(__curbrk))]
91#endif
92