From 3cf01adb3940f23808bcbf04d964bb15bed1ed5a Mon Sep 17 00:00:00 2001
From: Andreas Jaeger <aj@suse.de>
Date: Thu, 28 Mar 2002 19:07:58 +0000
Subject: Update.

2002-03-28  Andreas Jaeger  <aj@suse.de>

	* sysdeps/unix/sysv/linux/x86_64/swapcontext.S: New.
	* sysdeps/unix/sysv/linux/x86_64/getcontext.S: New.
	* sysdeps/unix/sysv/linux/x86_64/setcontext.S: New.
	* sysdeps/unix/sysv/linux/x86_64/ucontext_i.h: New.
---
 sysdeps/unix/sysv/linux/x86_64/swapcontext.S | 105 +++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 sysdeps/unix/sysv/linux/x86_64/swapcontext.S

(limited to 'sysdeps/unix/sysv/linux/x86_64/swapcontext.S')

diff --git a/sysdeps/unix/sysv/linux/x86_64/swapcontext.S b/sysdeps/unix/sysv/linux/x86_64/swapcontext.S
new file mode 100644
index 0000000000..3dddb3cec2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/swapcontext.S
@@ -0,0 +1,105 @@
+/* Save current context and install the given one.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Andreas Jaeger <aj@suse.de>, 2002.
+
+   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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <sysdep.h>
+
+#include "ucontext_i.h"
+
+
+/* int __swapcontext (ucontext_t *oucp, const ucontext_t *ucp);
+
+  Saves the machine context in oucp such that when it is activated,
+  it appears as if __swapcontextt() returned again, restores the
+  machine context in ucp and thereby resumes execution in that
+  context.
+
+  This implementation is intended to be used for *synchronous* context
+  switches only.  Therefore, it does not have to save anything
+  other than the PRESERVED state.  */
+
+ENTRY(__swapcontext)
+	/* Save the preserved registers and the return address.  */
+	movq	%rbx, oRBX(%rdi)
+	movq	%rbp, oRBP(%rdi)
+	movq	%r12, oR12(%rdi)
+	movq	%r13, oR13(%rdi)
+	movq	%r14, oR14(%rdi)
+	movq	%r15, oR15(%rdi)
+
+	movq	(%rsp), %rcx
+	movq	%rcx, oRIP(%rdi)
+	leaq	8(%rsp), %rcx		/* Exclude the return address.  */
+	movq	%rcx, oRSP(%rdi)
+
+	/* 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.  */
+	leaq	oFPREGSMEM(%rdi), %rcx
+	movq	%rcx, oFPREGS(%rdi)
+	/* Save the floating-point environment.  */
+	fnstenv	(%rcx)
+	stmxcsr oMXCSR(%rdi)
+
+
+	/* The syscall destroys some registers, save them.  */
+	movq	%rsi, %r12
+
+	/* Save the current signal mask and install the new one with
+	   rt_sigprocmask (SIG_BLOCK, newset, oldset,_NSIG/8).  */
+	leaq	oSIGMASK(%rdi), %rdx
+	leaq	oSIGMASK(%rsi), %rsi
+	movq	$SIG_SETMASK, %rdi
+	movq	$_NSIG8,%r10
+	movq	$__NR_rt_sigprocmask, %rax
+	syscall
+	cmpq	$-4095, %rax		/* Check %rax for error.  */
+	jae	SYSCALL_ERROR_LABEL	/* Jump to error handler if error.  */
+
+	/* Restore destroyed registers.  */
+	movq	%r12, %rsi
+
+	/* Restore the floating-point context.  Not the registers, only the
+	   rest.  */
+	movq	oFPREGS(%rsi), %rcx
+	fldenv	(%rcx)
+	ldmxcsr oMXCSR(%rsi)
+
+	/* Load the new stack pointer and the preserved registers.  */
+	movq	oRSP(%rsi), %rsp
+	movq	oRBX(%rsi), %rbx
+	movq	oRBP(%rsi), %rbp
+	movq	oR12(%rsi), %r12
+	movq	oR13(%rsi), %r13
+	movq	oR14(%rsi), %r14
+	movq	oR15(%rsi), %r15
+
+	/* The following ret should return to the address set with
+	getcontext.  Therefore push the address on the stack.  */
+	movq	oRIP(%rsi), %rcx
+	pushq	%rcx
+
+	/* Clear rax to indicate success.  */
+	xorq	%rax, %rax
+
+L(pseudo_end):
+	ret
+PSEUDO_END(__swapcontext)
+
+weak_alias(__swapcontext, swapcontext)
-- 
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