1/* $OpenBSD: brk.S,v 1.15 2020/10/26 22:07:05 gkoehler 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 .extern __curbrk 31 .extern _C_LABEL(_end) 32 33 .weak brk 34 35ENTRY(brk) 36 37 /* check >= _end, if not make the call for _end */ 38#ifndef __PIC__ 39 addis 5,0,_C_LABEL(_end)@h 40 ori 5,5,_C_LABEL(_end)@l /* # 5 = &_end */ 41#else 42 mflr 10 43 bcl 20, 31, 1f 441: mflr 9 45 addis 9, 9, _GLOBAL_OFFSET_TABLE_-1b@ha 46 addi 9, 9, _GLOBAL_OFFSET_TABLE_-1b@l 47 mtlr 10 48 lwz 5,_C_LABEL(_end)@got(9) 49#endif 50 cmplw 3,5 51 bge+ .L_brk_call 52 mr 3, 5 53 54.L_brk_call: 55 mr 7, 3 56 /* call break(size) */ 57#ifndef __PIC__ 58 addis 6, 0, __curbrk@H 59 ori 6, 6, __curbrk@L /* # 6 = &__curbrk */ 60#else 61 lwz 6,__curbrk@got(9) 62#endif 63 64 li 0, SYS_break 65 sc 66 67 /* check for error */ 68 cmpwi 0, 0 69 beq+ .L_brk_ok /* OK so this is stupid but I haven't read b */ 70 stw 0, R2_OFFSET_ERRNO(2) 71 li 3, -1 72 blr 73 74 /* update, __curbrk and return */ 75.L_brk_ok: 76 stw 7, 0(6) /* # remember, 6=&__curbrk, 3= new value */ 77 mr 3, 0 /* # return 0 */ 78 blr 79END(brk) 80