glibc/sysdeps/arm/arm-unwind-resume.S

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/* _Unwind_Resume wrapper for ARM EABI.
Copyright (C) 2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
/* This is just implementing exactly what the C version does.
We do it in assembly just to ensure that we get an unmolested tail
call to the libgcc function, which is necessary for the ARM unwinder. */
ENTRY (_Unwind_Resume)
LDR_HIDDEN (ip, ip, __libgcc_s_resume, 0)
cmp ip, #0
beq 1f
0: PTR_DEMANGLE (ip, ip, r2, r3)
bx ip
/* We need to save and restore LR (for our own return address)
and R0 (for the argument to _Unwind_Resume) around the call. */
1: push {r0, lr}
cfi_adjust_cfa_offset (8)
cfi_rel_offset (r0, 0)
cfi_rel_offset (lr, 4)
bl __libgcc_s_init
pop {r0, lr}
cfi_adjust_cfa_offset (-8)
cfi_restore (r0)
cfi_restore (lr)
LDR_HIDDEN (ip, ip, __libgcc_s_resume, 0)
b 0b
END (_Unwind_Resume)