1/* Copyright (C) 1991, 93, 96, 97, 98, 99, 2000 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, see 16 <http://www.gnu.org/licenses/>. */ 17 18#include <jmpbuf-offsets.h> 19 20#define ENV(base,reg) [%base + (reg * 4)] 21#define ST_FLUSH_WINDOWS 3 22#define RW_FP [%fp + 0x48] 23 24.global __longjmp 25.type __longjmp,%function 26.align 4 27__longjmp: 28 .register %g2, #scratch 29 .register %g3, #scratch 30 /* Store our arguments in global registers so we can still 31 * use them while unwinding frames and their register windows. */ 32 33 ld ENV(o0,JB_FP), %g3 /* Cache target FP in register %g3. */ 34 mov %o0, %g1 /* ENV in %g1 */ 35 orcc %o1, %g0, %g2 /* VAL in %g2 */ 36 be,a 0f /* Branch if zero; else skip delay slot. */ 37 mov 1, %g2 /* Delay slot only hit if zero: VAL = 1. */ 380: 39 xor %fp, %g3, %o0 40 add %fp, 512, %o1 41 andncc %o0, 4095, %o0 42 bne .Lthread 43 cmp %o1, %g3 44 bl .Lthread 45 46 /* Now we will loop, unwinding the register windows up the stack 47 * until the restored %fp value matches the target value in %g3. */ 48 49.Lloop: 50 cmp %fp, %g3 /* Have we reached the target frame? */ 51 bl,a .Lloop /* Loop while current fp is below target. */ 52 restore /* Unwind register window in delay slot. */ 53 be,a .Lfound /* Better have hit it exactly. */ 54 ld ENV(g1,JB_SP), %o0 /* Delay slot: extract target SP. */ 55 56.Lthread: 57 /* 58 * Do a "flush register windows trap". The trap handler in the 59 * kernel writes all the register windows to their stack slots, and 60 * marks them all as invalid (needing to be sucked up from the 61 * stack when used). This ensures that all information needed to 62 * unwind to these callers is in memory, not in the register 63 * windows. 64 */ 65 ta ST_FLUSH_WINDOWS 66 ld ENV(g1,JB_PC), %o7 /* Set return PC. */ 67 ld ENV(g1,JB_SP), %fp /* Set saved SP on restore below. */ 68 sub %fp, 64, %sp /* Allocate a register frame. */ 69 st %g3, RW_FP /* Set saved FP on restore below. */ 70 retl 71 restore %g2, 0, %o0 /* Restore values from above register frame. */ 72 73.Lfound: 74 /* We have unwound register windows so %fp matches the target. */ 75 mov %o0, %sp /* OK, install new SP. */ 76 77.Lsp_ok: 78 ld ENV(g1,JB_PC), %o0 /* Extract target return PC. */ 79 jmp %o0 + 8 /* Return there. */ 80 mov %g2, %o0 /* Delay slot: set return value. */ 81 82.size __longjmp,.-__longjmp 83 84libc_hidden_def(__longjmp) 85