From 3d5ccfc3c08dd64f1923c09956406890d88fbc1f Mon Sep 17 00:00:00 2001
From: bernie <bernie@38d2e660-2303-0410-9eaa-f027e97ec537>
Date: Sun, 10 Aug 2008 19:06:11 +0000
Subject: [PATCH] ppc: Add cooperative task switching for PowerPC

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@1611 38d2e660-2303-0410-9eaa-f027e97ec537
---
 bertos/cpu/attr.h        |  8 ++++++
 bertos/emul/switch.S     |  2 ++
 bertos/emul/switch_ppc.S | 57 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)
 create mode 100644 bertos/emul/switch_ppc.S

diff --git a/bertos/cpu/attr.h b/bertos/cpu/attr.h
index bfcb705e..28986936 100644
--- a/bertos/cpu/attr.h
+++ b/bertos/cpu/attr.h
@@ -353,6 +353,14 @@
 	 */
 	#define CPU_IDLE NOP
 
+#elif CPU_PPC
+
+	#define CPU_PUSH_CALL_CONTEXT(sp, func) \
+		do { \
+			CPU_PUSH_WORD((sp), (cpustack_t)(func)); /* LR -> 8(SP) */ \
+			CPU_PUSH_WORD((sp), 0);                  /* CR -> 4(SP) */ \
+		} while (0)
+
 #else
 	#define CPU_PUSH_CALL_CONTEXT(sp, func) \
 		CPU_PUSH_WORD((sp), (cpustack_t)(func))
diff --git a/bertos/emul/switch.S b/bertos/emul/switch.S
index ce87cdce..50567d19 100644
--- a/bertos/emul/switch.S
+++ b/bertos/emul/switch.S
@@ -2,6 +2,8 @@
 	#include "switch_i386.S"
 #elif defined(__x86_64__)
 	#include "switch_x86_64.s"
+#elif defined(_ARCH_PPC) || defined(_ARCH_PPC64)
+	#include "switch_ppc.S"
 #else
 	#error Unknown CPU
 #endif
diff --git a/bertos/emul/switch_ppc.S b/bertos/emul/switch_ppc.S
new file mode 100644
index 00000000..082efa8e
--- /dev/null
+++ b/bertos/emul/switch_ppc.S
@@ -0,0 +1,57 @@
+/**
+ * \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>
+ * -->
+ *
+ * \version $Id: switch_i386.S 1578 2008-08-08 10:54:40Z bernie $
+ * \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 */
-- 
2.25.1