-/*!
+/**
* \file
* <!--
- * Copyright 2004 Develer S.r.l. (http://www.develer.com/)
- * Copyright 1999,2000,2001 Bernardo Innocenti <bernie@develer.com>
- * This file is part of DevLib - See devlib/README for information.
+ * This file is part of BeRTOS.
+ *
+ * Bertos 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 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction. Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License. This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2004, 2008 Develer S.r.l. (http://www.develer.com/)
+ * Copyright 1999, 2000, 2001 Bernie Innocenti <bernie@codewiz.org>
* -->
*
+ * \author Bernie Innocenti <bernie@codewiz.org>
+ *
* \brief i386 context switch
*
- * \version $Id$
+ * x86 function calling convention:
+ * --------------------------------
+ * arguments | callee-saved | extra caller-saved | return
+ * [callee-clobbered] | | [callee-clobbered] |
+ * -------------------------------------------------------------------------
+ * eax edx ecx | ebx edi esi ebp [*] | <none> | eax, edx
*
- * \author Bernardo Innocenti <bernie@develer.com>
+ * [*] In the frame-pointers case rbp must hold a base address for the
+ * current stack frame.
+ *
+ * asm_switch_context() can be considered as a normal function call, so we need
+ * to save all the callee-clobbered registers minus the return registers.
*/
-/* void asm_switch_context(void ** new_sp, void ** save_sp) */
-.globl asm_switch_context
-asm_switch_context:
- pushl %eax
- pushl %ebx
- pushl %ecx
- pushl %edx
- pushl %esi
- pushl %edi
+#ifdef __APPLE__
+ // This workaround is necessary to compile under OS X assembler.
+ #define SWITCH_CONTEXT _asm_switch_context
+#else
+ #define SWITCH_CONTEXT asm_switch_context
+#endif
+
+/* void asm_switch_context(void ** new_sp [sp+4], void ** save_sp [sp+8]) */
+.globl SWITCH_CONTEXT
+SWITCH_CONTEXT:
pushl %ebp
- movl 0x24(%esp),%ebp /* ebp = save_sp */
+ pushl %ecx
+ movl 0x10(%esp),%ebp /* ebp = save_sp */
movl %esp,(%ebp) /* *save_sp = esp */
- movl 0x20(%esp),%ebp /* ebp = new_sp */
+ movl 0x0c(%esp),%ebp /* ebp = new_sp */
movl (%ebp),%esp /* esp = *new_sp */
- popl %ebp
- popl %edi
- popl %esi
- popl %edx
popl %ecx
- popl %ebx
- popl %eax
- ret
-
-/* int asm_switch_version(void) */
-.globl asm_switch_version
-asm_switch_version:
- mov $1,%eax
+ popl %ebp
ret
-