diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/i386/swapcontext.S')
| -rw-r--r-- | sysdeps/unix/sysv/linux/i386/swapcontext.S | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/swapcontext.S b/sysdeps/unix/sysv/linux/i386/swapcontext.S new file mode 100644 index 0000000000..5fdf76050b --- /dev/null +++ b/sysdeps/unix/sysv/linux/i386/swapcontext.S @@ -0,0 +1,129 @@ +/* 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) |