1 /* Save current context and install the given one.
2 Copyright (C) 2001-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
21 #include "ucontext_i.h"
25 /* Load address of the context data structure we save in. */
28 /* Save the preserved register values and the return address. */
38 /* Save the FS segment register. */
43 /* We have separate floating-point register content memory on the
44 stack. We use the __fpregs_mem block in the context. Set the
45 links up correctly. */
46 leal oFPREGSMEM(%eax), %ecx
47 movl %ecx, oFPREGS(%eax)
48 /* Save the floating-point context. */
51 /* Load address of the context data structure we have to load. */
54 /* Save the current signal mask and install the new one. */
56 leal oSIGMASK(%eax), %edx
57 leal oSIGMASK(%ecx), %ecx
58 movl $SIG_SETMASK, %ebx
59 movl $__NR_sigprocmask, %eax
62 cmpl $-4095, %eax /* Check %eax for error. */
63 jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */
65 /* EAX was modified, reload it. */
68 /* Restore the floating-point context. Not the registers, only the
70 movl oFPREGS(%eax), %ecx
73 /* Restore the FS segment register. We don't touch the GS register
74 since it is used for threads. */
78 /* Fetch the address to return to. */
81 /* Load the new stack pointer. */
84 /* Push the return address on the new stack so we can return there. */
87 /* Load the values of all the preserved registers (except ESP). */
93 /* All done, return 0 for success. */
96 /* The following 'ret' will pop the address of the code and jump
99 PSEUDO_END(__swapcontext)
101 weak_alias (__swapcontext, swapcontext)