sbrk.S revision 1.16
1/* $OpenBSD: sbrk.S,v 1.16 2022/06/10 01:56:02 guenther Exp $ */ 2 3/* 4 * Copyright (c) 1996 Dale Rahn 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28#include "SYS.h" 29 30 .data 31 .globl _end 32 .globl __curbrk 33 .hidden __curbrk 34__curbrk: 35 .long _C_LABEL(_end) 36 END(__curbrk) 37 .type __curbrk,@object 38 39 .text 40ENTRY_NB(sbrk) 41 42 /* call break(__curbrk + size) */ 43#ifndef __PIC__ 44 addis 6, 0, __curbrk@H 45 ori 6, 6, __curbrk@L /* # 6 = &__curbrk */ 46#else 47 mflr 10 48 bcl 20, 31, 1f 491: mflr 9 50 addis 9, 9, _GLOBAL_OFFSET_TABLE_-1b@ha 51 addi 9, 9, _GLOBAL_OFFSET_TABLE_-1b@l 52 mtlr 10 53 lwz 6,__curbrk@got(9) 54#endif 55 lwz 5, 0(6) /* # 5 = *6 (old_curbrk) */ 56 add 3, 5, 3 /* # 3 = new_curbrk */ 57 mr 7, 3 58 59 li 0, SYS_break 60 sc 61 62 /* check for error */ 63 cmpwi 0, 0 64 beq+ .L_sbrk_ok 65 stw 0, R2_OFFSET_ERRNO(2) 66 li 3, -1 67 blr 68 69 /* update, __curbrk and return */ 70.L_sbrk_ok: 71 stw 7, 0(6) /* # remember, 6=&__curbrk, 7=new_curbrk */ 72 mr 3, 5 /* # remember, 5=old_curbrk */ 73 blr 74END(sbrk) 75 .weak sbrk 76