xref: /netbsd-src/lib/libc/arch/i386/sys/brk.S (revision ae9172d6cd9432a6a1a56760d86b32c57a66c39c)
1/*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * William Jolitz.
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. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 *	from: @(#)brk.s	5.2 (Berkeley) 12/17/90
37 *	$Id: brk.S,v 1.9 1994/10/26 19:49:45 mycroft Exp $
38 */
39
40#if defined(SYSLIBC_SCCS) && !defined(lint)
41	.text
42	.asciz "$Id: brk.S,v 1.9 1994/10/26 19:49:45 mycroft Exp $"
43#endif /* SYSLIBC_SCCS and not lint */
44
45#include "SYS.h"
46
47	.globl	_end
48	.globl	minbrk
49	.globl	curbrk
50
51	.data
52minbrk:	.long	_end
53	.text
54
55ENTRY(brk)
56#ifdef PIC
57	movl	4(%esp),%ecx
58	PIC_PROLOGUE
59	movl	PIC_GOT(minbrk),%edx
60	PIC_EPILOGUE
61	cmpl	%ecx,(%edx)
62	jl	1f
63	movl	(%edx),%ecx
64	movl	%ecx,4(%esp)
651:
66	movl	$(SYS_break),%eax
67	int	$0x80
68	jc	err
69	PIC_PROLOGUE
70	movl	PIC_GOT(curbrk),%edx	# set up GOT addressing
71	PIC_EPILOGUE
72	xorl	%eax,%eax
73	movl	%ecx,(%edx)
74	ret
75err:
76	jmp	PIC_PLT(cerror)
77
78#else
79
80	movl	4(%esp),%ecx
81	cmpl	%ecx,minbrk
82	jl	1f
83	movl	minbrk,%ecx
84	movl	%ecx,4(%esp)
851:
86	movl	$(SYS_break),%eax
87	int	$0x80
88	jc	err
89	xorl	%eax,%eax
90	movl	%ecx,curbrk
91	ret
92err:
93	jmp	cerror
94#endif
95