Working

bertos/emul/switch_ppc.S

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+/**
+ * \file
+ * <!--
+ * 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 2008 Bernie Innocenti <bernie@codewiz.org>
+ * -->
+ *
+ * \author Bernie Innocenti <bernie@codewiz.org>
+ *
+ * \brief PowerPC context switch
+ */
+
+#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
+
+.balign 4
+
+/* void asm_switch_context(void ** new_sp, void ** save_sp) */
+/*                                 r3              r4       */
+.globl SWITCH_CONTEXT
+SWITCH_CONTEXT:
+	mflr	0		/* r0 = lr */
+	stw	0,8(1)		/* store lr at *(sp+8) */
+	stw	1,0(4)		/* *save_sp = sp */
+	lwz	1,0(3)		/* sp = *new_sp */
+	lwz	0,8(1)		/* retrieve lr from *(sp+8) */
+	mtlr	0		/* lr = r0 */
+	blr			/* return */