brk.S revision 1.12 
1/*	$OpenBSD: brk.S,v 1.12 2023/12/10 16:45:52 deraadt 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. 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
37#include <machine/asm.h>
38
39#include "SYS.h"
40
41	.globl	__curbrk
42	.globl	_end
43
44	.data
45	.align	8
46__minbrk:
47	.xword	_end			/* lower brk limit; also for gmon code */
48	END(__minbrk)
49	OTYPE(__minbrk)
50	.text
51
52ENTRY_NB(brk)
53#ifdef __PIC__
54	PIC_PROLOGUE(%o5, %o4)
55	set	__minbrk, %o4
56	ldx	[%o5 + %o4], %o4
57	ldx	[%o4], %o1		/* %o1 = minbrk */
58	cmp	%o1, %o0		/* if (minbrk > %o0) */
59	movgu	%xcc, %o1, %o0		/*	%o0 = minbrk */
60	mov	%o0, %o2		/* save argument to syscall */
61	mov	SYS_break, %g1
6299:	t	ST_SYSCALL
63	PINSYSCALL(SYS_break, 99b)
64	set	__curbrk, %o3
65	bcc,a,pt	%icc, 1f
66	 ldx	[%o5 + %o3], %o4
67	ERROR()
681:
69	retl				/* success, return 0 & record new break */
70	 stx	%o2, [%o4]
71#else
72	sethi	%hi(__minbrk), %o1	/* %o1 = minbrk */
73	ldx	[%o1 + %lo(__minbrk)], %o1
74	cmp	%o1, %o0		/* if (minbrk > %o0) */
75	movgu	%xcc, %o1, %o0		/*	%o0 = minbrk */
76	mov	%o0, %o2		/* save argument to syscall */
77	mov	SYS_break, %g1
7898:	t	ST_SYSCALL
79	PINSYSCALL(SYS_break, 98b)
80	bcc,a,pt	%icc,1f
81	 sethi	%hi(__curbrk), %g1
82	ERROR()
831:
84	retl				/* success, return 0 & record new break */
85	 stx	%o2, [%g1 + %lo(__curbrk)]
86#endif
87END(brk)
88	.weak	brk
89