diff options
Diffstat (limited to 'ports/sysdeps/unix/sysv/linux/arm/swapcontext.S')
| -rw-r--r-- | ports/sysdeps/unix/sysv/linux/arm/swapcontext.S | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/ports/sysdeps/unix/sysv/linux/arm/swapcontext.S b/ports/sysdeps/unix/sysv/linux/arm/swapcontext.S new file mode 100644 index 0000000000..09492d0000 --- /dev/null +++ b/ports/sysdeps/unix/sysv/linux/arm/swapcontext.S @@ -0,0 +1,63 @@ +/* Copyright (C) 2012 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> + +#include "ucontext_i.h" + + .syntax unified + .text + +/* int swapcontext (ucontext_t *oucp, const ucontext_t *ucp) */ + +ENTRY(swapcontext) + + /* Have getcontext() do most of the work then fix up + LR afterwards. Save R3 to keep the stack aligned. */ + push {r0,r1,r3,r14} + cfi_adjust_cfa_offset (16) + cfi_rel_offset (r0,0) + cfi_rel_offset (r1,4) + cfi_rel_offset (r3,8) + cfi_rel_offset (r14,12) + + bl __getcontext + mov r4, r0 + + pop {r0,r1,r3,r14} + cfi_adjust_cfa_offset (-16) + cfi_restore (r0) + cfi_restore (r1) + cfi_restore (r3) + cfi_restore (r14) + + /* Exit if getcontext() failed. */ + cmp r4, #0 + itt ne + movne r0, r4 + RETINSTR(ne, r14) + + /* Fix up LR and the PC. */ + str r13,[r0, #MCONTEXT_ARM_SP] + str r14,[r0, #MCONTEXT_ARM_LR] + str r14,[r0, #MCONTEXT_ARM_PC] + + /* And swap using swapcontext(). */ + mov r0, r1 + b __setcontext + +END(swapcontext) |