diff options
Diffstat (limited to 'libc/sysdeps/linux/x86_64/getcontext.S')
| -rw-r--r-- | libc/sysdeps/linux/x86_64/getcontext.S | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/x86_64/getcontext.S b/libc/sysdeps/linux/x86_64/getcontext.S new file mode 100644 index 000000000..dcebc4f29 --- /dev/null +++ b/libc/sysdeps/linux/x86_64/getcontext.S @@ -0,0 +1,88 @@ +/* Save current context. + Copyright (C) 2002-2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Andreas Jaeger <aj@suse.de>, 2002. + + 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" + +/* int __getcontext (ucontext_t *ucp) + + Saves the machine context in UCP such that when it is activated, + it appears as if __getcontext() returned again. + + This implementation is intended to be used for *synchronous* context + switches only. Therefore, it does not have to save anything + other than the PRESERVED state. */ + + +ENTRY(__getcontext) + /* Save the preserved registers, the registers used for passing + args, and the return address. */ + movq %rbx, oRBX(%rdi) + movq %rbp, oRBP(%rdi) + movq %r12, oR12(%rdi) + movq %r13, oR13(%rdi) + movq %r14, oR14(%rdi) + movq %r15, oR15(%rdi) + + movq %rdi, oRDI(%rdi) + movq %rsi, oRSI(%rdi) + movq %rdx, oRDX(%rdi) + movq %rcx, oRCX(%rdi) + movq %r8, oR8(%rdi) + movq %r9, oR9(%rdi) + + movq (%rsp), %rcx + movq %rcx, oRIP(%rdi) + leaq 8(%rsp), %rcx /* Exclude the return address. */ + movq %rcx, oRSP(%rdi) + + /* We have separate floating-point register content memory on the + stack. We use the __fpregs_mem block in the context. Set the + links up correctly. */ + + leaq oFPREGSMEM(%rdi), %rcx + movq %rcx, oFPREGS(%rdi) + /* Save the floating-point environment. */ + fnstenv (%rcx) + fldenv (%rcx) + stmxcsr oMXCSR(%rdi) + + /* Save the current signal mask with + rt_sigprocmask (SIG_BLOCK, NULL, set,_NSIG/8). */ + leaq oSIGMASK(%rdi), %rdx + xorl %esi,%esi +#if SIG_BLOCK == 0 + xorl %edi, %edi +#else + movl $SIG_BLOCK, %edi +#endif + movl $_NSIG8,%r10d + movl $__NR_rt_sigprocmask, %eax + syscall + cmpq $-4095, %rax /* Check %rax for error. */ + jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */ + + /* All done, return 0 for success. */ + xorl %eax, %eax +L(pseudo_end): + ret +PSEUDO_END(__getcontext) + +weak_alias (__getcontext, getcontext) |