/* Save current context and install the given one.
Copyright (C) 2001-2024 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
. */
#include
#include "ucontext_i.h"
ENTRY(__swapcontext)
/* Load address of the context data structure we save in. */
movl 4(%esp), %eax
/* Save the preserved register values and the return address. */
movl %edi, oEDI(%eax)
movl %esi, oESI(%eax)
movl %ebp, oEBP(%eax)
movl (%esp), %ecx
movl %ecx, oEIP(%eax)
leal 4(%esp), %ecx
movl %ecx, oESP(%eax)
movl %ebx, oEBX(%eax)
/* Save the FS segment register. */
xorl %edx, %edx
movw %fs, %dx
movl %edx, oFS(%eax)
/* 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. */
leal oFPREGSMEM(%eax), %ecx
movl %ecx, oFPREGS(%eax)
/* Save the floating-point context. */
fnstenv (%ecx)
/* Load address of the context data structure we have to load. */
movl 8(%esp), %ecx
/* Save the current signal mask and install the new one. */
pushl %ebx
leal oSIGMASK(%eax), %edx
leal oSIGMASK(%ecx), %ecx
movl $SIG_SETMASK, %ebx
movl $__NR_sigprocmask, %eax
ENTER_KERNEL
popl %ebx
cmpl $-4095, %eax /* Check %eax for error. */
jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */
/* EAX was modified, reload it. */
movl 8(%esp), %eax
/* Restore the floating-point context. Not the registers, only the
rest. */
movl oFPREGS(%eax), %ecx
fldenv (%ecx)
/* Restore the FS segment register. We don't touch the GS register
since it is used for threads. */
movl oFS(%eax), %edx
movw %dx, %fs
/* Fetch the address to return to. */
movl oEIP(%eax), %ecx
/* Load the new stack pointer. */
movl oESP(%eax), %esp
/* Push the return address on the new stack so we can return there. */
pushl %ecx
/* Load the values of all the preserved registers (except ESP). */
movl oEDI(%eax), %edi
movl oESI(%eax), %esi
movl oEBP(%eax), %ebp
movl oEBX(%eax), %ebx
/* All done, return 0 for success. */
xorl %eax, %eax
/* The following 'ret' will pop the address of the code and jump
to it. */
ret
PSEUDO_END(__swapcontext)
weak_alias (__swapcontext, swapcontext)