2004-04-15 Marcus Brinkmann <marcus@gnu.org>

	* Initial check-in.

1 files changed, 112 insertions, 0 deletions

diff --git a/task/ia32-cmain.c b/task/ia32-cmain.c
new file mode 100644
index 0000000..4443ea1
--- /dev/null
+++ b/task/ia32-cmain.c
@@ -0,0 +1,112 @@
+/* ia32-cmain.c - Startup code for the ia32.
+   Copyright (C) 2003 Free Software Foundation, Inc.
+   Written by Marcus Brinkmann.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd 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, or (at
+   your option) any later version.
+
+   The GNU Hurd 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, USA. */
+
+#if HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <alloca.h>
+#include <stdint.h>
+
+#include <l4/globals.h>
+#include <l4/init.h>
+#include <l4/stubs.h>
+#include <l4/stubs-init.h>
+
+#include "task.h"
+
+
+/* Initialize libl4, setup the argument vector, and pass control over
+   to the main function.  */
+void
+cmain (void)
+{
+  int argc = 0;
+  char **argv = 0;
+
+  l4_init ();
+  l4_init_stubs ();
+
+  argc = 1;
+  argv = alloca (sizeof (char *) * 2);
+  argv[0] = program_name;
+  argv[1] = 0;
+
+  /* Now invoke the main function.  */
+  main (argc, argv);
+
+  /* Never reached.  */
+}
+
+
+#define __thread_stack_pointer() ({					      \
+  void *__sp__;								      \
+  __asm__ ("movl %%esp, %0" : "=r" (__sp__));				      \
+  __sp__;								      \
+})
+
+
+#define __thread_set_stack_pointer(sp) ({				      \
+  __asm__ ("movl %0, %%esp" : : "r" (sp));				      \
+})
+
+
+/* Switch execution transparently to thread TO.  The thread FROM,
+   which must be the current thread, will be halted.  */
+void
+switch_thread (l4_thread_id_t from, l4_thread_id_t to)
+{
+  void *current_stack;
+  /* FIXME: Figure out how much we need.  Probably only one return
+     address.  */
+  char small_sub_stack[16];
+  unsigned int i;
+
+/* FIXME: FROM is an argument to force gcc to evaluate it before the
+   thread switch.  Maybe this can be done better, but it's
+   magical, so be careful.  */
+
+  /* Save the machine context.  */
+  __asm__ __volatile__ ("pusha");
+  __asm__ __volatile__ ("pushf");
+
+  /* Start the TO thread.  It will be eventually become a clone of our
+     thread.  */
+  current_stack = __thread_stack_pointer ();
+  l4_start_sp_ip (to, (l4_word_t) current_stack,
+		  (l4_word_t) &&thread_switch_entry);
+  
+  /* We need a bit of extra space on the stack for
+     l4_thread_switch.  */
+  __thread_set_stack_pointer (small_sub_stack);
+
+  /* We can't use while(1), because then gcc will become clever and
+     optimize away everything after thread_switch_entry.  */
+  for (i = 1; i; i++)
+    l4_thread_switch (to);
+
+ thread_switch_entry:
+  /* Restore the machine context.  */
+  __asm__ __volatile__ ("popf");
+  __asm__ __volatile__ ("popa");
+
+  /* The thread TO continues here.  */
+  l4_stop (from);
+}