1/* $OpenBSD: sbrk.S,v 1.5 2023/12/10 16:45:52 deraadt 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 .quad _end 36 END(__curbrk) 37 .type __curbrk,@object 38 39 .weak sbrk 40 41 .text 42SYSENTRY(sbrk) 43 RETGUARD_SETUP(sbrk, %r11) 44 45 /* call break(__curbrk + size) */ 46 addis %r6, %r2, __curbrk@toc@ha 47 addi %r6, %r6, __curbrk@toc@l /* # %r6 = &__curbrk */ 48 49 ld %r5, 0(%r6) /* # %r5 = *%r6 (old_curbrk) */ 50 add %r3, %r5, %r3 /* # %r3 = new_curbrk */ 51 mr %r7, %r3 52 53 li %r0, SYS_break 5499: sc 55 PINSYSCALL(SYS_break, 99b) 56 57 /* check for error */ 58 cmpwi %r0, 0 59 beq+ .L_sbrk_ok 60 stw %r0, R13_OFFSET_ERRNO(%r13) 61 li %r3, -1 62 b .L_done 63 64 /* update, __curbrk and return */ 65.L_sbrk_ok: 66 std %r7, 0(%r6) /* # remember, %r6=&__curbrk, %r7=new_curbrk */ 67 mr %r3, %r5 /* # remember, %r5=old_curbrk */ 68.L_done: 69 RETGUARD_CHECK(sbrk, %r11); 70 blr 71 END(sbrk) 72