brk.S revision 1.7
1/* $OpenBSD: brk.S,v 1.7 2015/09/05 06:22:47 guenther Exp $ */ 2/* $NetBSD: brk.S,v 1.2 2002/06/03 18:30:33 fvdl Exp $ */ 3 4/*- 5 * Copyright (c) 1990 The Regents of the University of California. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * William Jolitz. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * from: @(#)brk.s 5.2 (Berkeley) 12/17/90 36 */ 37 38#include <machine/asm.h> 39 40#include "SYS.h" 41 42 .globl _end 43 .globl __curbrk 44 45 .data 46__minbrk: 47 .quad _end 48 END(__minbrk) 49 .type __minbrk,@object 50 .text 51 52 .weak brk 53ENTRY(brk) 54#ifdef __PIC__ 55 movq PIC_GOT(__minbrk),%rdx 56 cmpq %rdi,(%rdx) 57 jb 1f 58 movq (%rdx),%rdi 591: 60 SYSTRAP(break) 61 jc 1f 62 movq PIC_GOT(__curbrk),%rdx # set up GOT addressing 63 movq %rdi,(%rdx) 64 xorl %eax,%eax 65 ret 661: 67 movq PIC_GOT(CERROR),%rdx 68 jmp *%rdx 69#else 70 cmpq %rdi,__minbrk(%rip) 71 jb 1f 72 movq __minbrk(%rip),%rdi 731: 74 SYSTRAP(break) 75 jc 1f 76 movq %rdi,__curbrk(%rip) 77 xorl %eax,%eax 78 ret 791: 80 jmp CERROR 81#endif 82END(brk) 83