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##--------------------------------------------------------------------##
##--- Support for doing system calls. ---##
##--- vg_syscall.S ---##
##--------------------------------------------------------------------##
/*
This file is part of Valgrind, an x86 protected-mode emulator
designed for debugging and profiling binaries on x86-Unixes.
Copyright (C) 2000-2002 Julian Seward
jseward@acm.org
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307, USA.
The GNU General Public License is contained in the file LICENSE.
*/
#include "vg_constants.h"
.globl VG_(do_syscall)
# NOTE that this routine expects the simulated machines state
# to be in m_state_static. Therefore it needs to be wrapped by
# code which copies from baseBlock before the call, into
# m_state_static, and back afterwards.
VG_(do_syscall):
# Save all the int registers of the real machines state on the
# simulators stack.
pushal
# and save the real FPU state too
fwait
fnsave VG_(real_fpu_state_saved_over_syscall_d1)
frstor VG_(real_fpu_state_saved_over_syscall_d1)
# remember what the simulators stack pointer is
movl %esp, VG_(esp_saved_over_syscall_d1)
# Now copy the simulated machines state into the real one
# esp still refers to the simulators stack
frstor VG_(m_state_static)+40
movl VG_(m_state_static)+32, %eax
pushl %eax
popfl
movl VG_(m_state_static)+0, %eax
movl VG_(m_state_static)+4, %ecx
movl VG_(m_state_static)+8, %edx
movl VG_(m_state_static)+12, %ebx
movl VG_(m_state_static)+16, %esp
movl VG_(m_state_static)+20, %ebp
movl VG_(m_state_static)+24, %esi
movl VG_(m_state_static)+28, %edi
# esp now refers to the simulatees stack
# Do the actual system call
int $0x80
# restore stack as soon as possible
# esp refers to simulatees stack
movl %esp, VG_(m_state_static)+16
movl VG_(esp_saved_over_syscall_d1), %esp
# esp refers to simulators stack
# ... and undo everything else.
# Copy real state back to simulated state.
movl %eax, VG_(m_state_static)+0
movl %ecx, VG_(m_state_static)+4
movl %edx, VG_(m_state_static)+8
movl %ebx, VG_(m_state_static)+12
movl %ebp, VG_(m_state_static)+20
movl %esi, VG_(m_state_static)+24
movl %edi, VG_(m_state_static)+28
pushfl
popl %eax
movl %eax, VG_(m_state_static)+32
fwait
fnsave VG_(m_state_static)+40
frstor VG_(m_state_static)+40
# Restore the state of the simulator
frstor VG_(real_fpu_state_saved_over_syscall_d1)
popal
ret
##--------------------------------------------------------------------##
##--- end vg_syscall.S ---##
##--------------------------------------------------------------------##