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/* Save current context and install the given one.
Copyright (C) 2001 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2001.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <sysdep.h>
#include "ucontext_i.h"
ENTRY(__swapcontext)
/* Load address of the context data structure we save in. */
movl 4(%esp), %eax
/* Return value of swapcontext. EAX is the only register whose
value is not preserved. */
movl $0, oEAX(%eax)
/* Save the 32-bit register values and the return address. */
movl %ecx, oECX(%eax)
movl %edx, oEDX(%eax)
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 and GS segment register. */
xorl %edx, %edx
xorl %ecx, %ecx
movw %gs, %dx
movw %fs, %cx
movl %edx, oGS(%eax)
movl %ecx, 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
int $0x80
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 and GS segment registers. */
movl oGS(%eax), %edx
movl oFS(%eax), %ecx
movw %dx, %gs
movw %cx, %fs
/* Load the new stack pointer. */
movl oESP(%eax), %ecx
/* Make room for 8 registers and the return address. We will load
the values from the stack. */
subl $36, %ecx
/* Move the values of all the 32-bit registers (except ESP) on
the stack. This happens in the form the 'popa' instruction
expects it. Before this block put the address of the code
to execute. */
movl oEDI(%eax), %ebx
movl oESI(%eax), %edx
movl oEBP(%eax), %esi
movl oEBX(%eax), %edi
movl %ebx, (%ecx)
movl %edx, 4(%ecx)
movl %esi, 8(%ecx)
movl %edi, 16(%ecx)
movl oEDX(%eax), %ebx
movl oECX(%eax), %edx
movl oEAX(%eax), %esi
movl oEIP(%eax), %edi
movl %ebx, 20(%ecx)
movl %edx, 24(%ecx)
movl %esi, 28(%ecx)
movl %edi, 32(%ecx)
/* Set the new stack address. The stack points now to the block
we put the register content in. */
movl %ecx, %esp
/* Restore the register content. */
popa
/* The following 'ret' will pop the addres of the code and jump
to it. */
L(pseudo_end):
ret
PSEUDO_END(__swapcontext)
weak_alias(__swapcontext, swapcontext)
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