Update.

2001-04-07  Ulrich Drepper  <drepper@redhat.com>

	* sysdeps/unix/sysv/linux/i386/getcontext.S: New file.
	* sysdeps/unix/sysv/linux/i386/setcontext.S: New file.
	* sysdeps/unix/sysv/linux/i386/makecontext.S: New file.
	* sysdeps/unix/sysv/linux/i386/swapcontext.S: New file.
	* sysdeps/unix/sysv/linux/i386/ucontext_i.h: New file.
	* sysdeps/unix/sysv/linux/i386/Dist: Add ucontext_i.h.

5 files changed, 380 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/i386/Dist b/sysdeps/unix/sysv/linux/i386/Dist
index e08e6bec06..30a5b63c81 100644
--- a/sysdeps/unix/sysv/linux/i386/Dist
+++ b/sysdeps/unix/sysv/linux/i386/Dist
@@ -14,3 +14,4 @@ sys/procfs.h
 sys/reg.h
 sys/user.h
 sys/vm86.h
+ucontext_i.h
diff --git a/sysdeps/unix/sysv/linux/i386/makecontext.S b/sysdeps/unix/sysv/linux/i386/makecontext.S
new file mode 100644
index 0000000000..a68e66c3f5
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/makecontext.S
@@ -0,0 +1,113 @@
+/* Create new 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(__makecontext)
+	movl	4(%esp), %eax
+
+	/* Load the address of the function we are supposed to run.  */
+	movl	8(%esp), %ecx
+
+	/* Compute the address of the stack.  The information comes from
+	   to us_stack element.  */
+	movl	oSS_SP(%eax), %edx
+	movl	%ecx, oEIP(%eax)
+	addl	oSS_SIZE(%eax), %edx
+
+	/* Put the next context on the new stack (from the uc_link
+	   element).  */
+	movl	oLINK(%eax), %ecx
+	movl	%ecx, -4(%edx)
+
+	/* Remember the number of parameters for the exit handler since
+	   it has to remove them.  We store the number in the EBX register
+	   which the function we will call must preserve.  */
+	movl	12(%esp), %ecx
+	movl	%ecx, oEBX(%eax)
+
+	/* Make room on the new stack for the parameters.  */
+	negl	%ecx
+	leal	-8(%edx,%ecx,4), %edx
+	negl	%ecx
+	/* Store the future stack pointer.  */
+	movl	%edx, oESP(%eax)
+
+	/* Copy all the parameters.  */
+	jecxz	2f
+1:	movl	12(%esp,%ecx,4), %eax
+	movl	%eax, (%edx,%ecx,4)
+	decl	%ecx
+	jnz	1b
+2:
+
+	/* If the function we call returns we must continue with the
+	   context which is given in the uc_link element.  To do this
+	   set the return address for the function the user provides
+	   to a little bit of helper code which does the magic (see
+	   below).  */
+#ifdef PIC
+	call	1f
+1:	popl	%ecx
+	addl	$L(exitcode)-1b, %ecx
+	movl	%ecx, (%edx)
+#else
+	movl	$L(exitcode), (%edx)
+#endif
+	/* 'makecontext' returns no value.  */
+	ret
+
+	/* This is the helper code which gets called if a function which
+	   is registered with 'makecontext' returns.  In this case we
+	   have to install the context listed in the uc_link element of
+	   the context 'makecontext' manipulated at the time of the
+	   'makecontext' call.  If the pointer is NULL the process must
+	   terminate.  */
+L(exitcode):
+	/* This removes the parameters passed to the function given to
+	   'makecontext' from the stack.  EBX contains the number of
+	   parameters (see above).  */
+	leal	(%esp,%ebx,4), %esp
+
+#ifdef	PIC
+	call	1f
+1:	popl	%ebx
+	addl	$_GLOBAL_OFFSET_TABLE_+[.-1b], %ebx
+#endif
+	popl	%eax			/* This is the next context.  */
+	testl	%eax, %eax
+	je	2f			/* If it is zero exit.  */
+
+	pushl	%eax
+	call	JUMPTARGET(__setcontext)
+	/* If this returns (which can happen if the syscall fails) we'll
+	   exit the program with the return error value (-1).  */
+
+2:	pushl	%eax
+	call	JUMPTARGET(exit)
+	/* The 'exit' call should never return.  In case it does cause
+	   the process to terminate.  */
+	hlt
+END(__makecontext)
+
+weak_alias(__makecontext, makecontext)
diff --git a/sysdeps/unix/sysv/linux/i386/setcontext.S b/sysdeps/unix/sysv/linux/i386/setcontext.S
new file mode 100644
index 0000000000..cd4b1bfe8a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/setcontext.S
@@ -0,0 +1,96 @@
+/* Install given 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(__setcontext)
+	/* Load address of the context data structure.  */
+	movl	4(%esp), %eax
+
+	/* Get the current signal mask.  Note that we preserve EBX in case
+	   the system call fails and we return from the function with an
+	   error.  */
+	pushl	%ebx
+	xorl	%edx, %edx
+	leal	oSIGMASK(%eax), %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	4(%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(__setcontext)
+
+weak_alias(__setcontext, setcontext)
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)
diff --git a/sysdeps/unix/sysv/linux/i386/ucontext_i.h b/sysdeps/unix/sysv/linux/i386/ucontext_i.h
new file mode 100644
index 0000000000..863c1adb7a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/ucontext_i.h
@@ -0,0 +1,41 @@
+/* Offsets and other constants needed in the *context() function
+   implementation.
+   Copyright (C) 2001 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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.  */
+
+#define SIG_BLOCK	0
+#define SIG_SETMASK	2
+
+/* Offsets of the fields in the ucontext_t structure.  */
+#define oLINK		4
+#define oSS_SP		8
+#define oSS_SIZE	16
+#define oGS		20
+#define oFS		24
+#define oEDI		36
+#define oESI		40
+#define oEBP		44
+#define oESP		48
+#define oEBX		52
+#define oEDX		56
+#define oECX		60
+#define oEAX		64
+#define oEIP		76
+#define oFPREGS		96
+#define oSIGMASK	108
+#define oFPREGSMEM	236