xref: /dragonfly/lib/libc/x86_64/sys/fake_sbrk.S (revision e5a92d33)
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. 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 * @(#)sbrk.s	5.1 (Berkeley) 4/23/90
33 * $FreeBSD: src/lib/libc/amd64/sys/sbrk.S,v 1.15 2008/11/02 01:10:54 peter Exp $
34 */
35
36#include <machine/asm.h>
37#include "SYS.h"
38
39	.globl	CNAME(_end)
40	.globl	HIDENAME(minbrk)
41	.globl	HIDENAME(curbrk)
42
43	.data
44HIDENAME(minbrk):	.quad	CNAME(_end)
45HIDENAME(curbrk):	.quad	CNAME(_end)
46	.text
47
48ENTRY(fake_sbrk)
49	pushq	%rdi
50	movq	%rdi,%rcx
51#ifdef PIC
52	movq	PIC_GOT(HIDENAME(curbrk)),%rdx
53	movq	(%rdx),%rax
54#else
55	movq	HIDENAME(curbrk)(%rip),%rax
56#endif
57	testq	%rcx,%rcx
58	jz	back
59	addq	%rax,%rdi
60	mov	$SYS_break,%eax
61	KERNCALL
62	jb	err
63#ifdef PIC
64	movq	PIC_GOT(HIDENAME(curbrk)),%rdx
65	movq	(%rdx),%rax
66#else
67	movq	HIDENAME(curbrk)(%rip),%rax
68#endif
69	movq	0(%rsp), %rcx
70#ifdef PIC
71	addq	%rcx,(%rdx)
72#else
73	addq	%rcx,HIDENAME(curbrk)(%rip)
74#endif
75back:
76	addq	$8, %rsp
77	ret
78err:
79	addq	$8, %rsp
80#ifdef PIC
81	movq	PIC_GOT(HIDENAME(cerror)),%rdx
82	jmp	*%rdx
83#else
84	jmp	HIDENAME(cerror)
85#endif
86END(fake_sbrk)
87
88	.section .note.GNU-stack,"",%progbits
89