getcontext implementation for Linux/x86.

sysdeps/unix/sysv/linux/i386/getcontext.S

@@ -0,0 +1,79 @@
+/* Save current context.
+   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(__getcontext)
+	/* Load address of the context data structure.  */
+	movl	4(%esp), %eax
+
+	/* Return value of getcontext.  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		/* Exclude the return address.  */
+	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)
+
+	/* Save the current signal mask.  */
+	pushl	%ebx
+	leal	oSIGMASK(%eax), %edx
+	xorl	%ecx, %ecx
+	movl	$SIG_BLOCK, %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.  */
+
+	/* All done, return 0 for success.  */
+	xorl	%eax, %eax
+L(pseudo_end):
+	ret
+PSEUDO_END(__getcontext)
+
+weak_alias(__getcontext, getcontext)