From f709a37e5659fd591b5a61d80b45257105ac1850 Mon Sep 17 00:00:00 2001
From: batt <batt@38d2e660-2303-0410-9eaa-f027e97ec537>
Date: Thu, 10 Sep 2009 13:53:01 +0000
Subject: [PATCH] New macro to fill a new process stack: in this way the stack
 is always aligned.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@2928 38d2e660-2303-0410-9eaa-f027e97ec537
---
 bertos/cpu/frame.h | 56 +++++++++++++++++++++++++++++++++++-----------
 bertos/kern/proc.c | 14 +++---------
 2 files changed, 46 insertions(+), 24 deletions(-)

diff --git a/bertos/cpu/frame.h b/bertos/cpu/frame.h
index 1a80fa1d..2244b3b1 100644
--- a/bertos/cpu/frame.h
+++ b/bertos/cpu/frame.h
@@ -64,24 +64,37 @@
 
 	/**
 	 * Initialization value for registers in stack frame.
-	 * The register index is not directly corrispondent to CPU
-	 * register numbers, but is related to how are pushed to
-	 * stack (\see asm_switch_context).
-	 * Index (CPU_SAVED_REGS_CNT - 1) is the CPSR register,
-	 * the initial value is set to:
+	 * For the CPSR register, the initial value is set to:
 	 * - All flags (N, Z, C, V) set to 0.
 	 * - IRQ and FIQ enabled.
 	 * - ARM state.
 	 * - CPU in Supervisor Mode (SVC).
 	 */
-	#define CPU_REG_INIT_VALUE(reg) \
-	({  int a = 0; \
-		if(reg == 0) \
-			a = (int)proc_exit; \
-		else if(reg == (CPU_SAVED_REGS_CNT - 1)) \
-			a = 0x13; \
-		a; \
-	})
+	#define CPU_CREATE_NEW_STACK(stack, entry, exit) \
+	do { \
+		/* Process entry point */ \
+		CPU_PUSH_CALL_FRAME(stack, entry); \
+		/* LR (proc_exit) */ \
+		CPU_PUSH_CALL_FRAME(stack, exit); \
+		/* R11 */ \
+		CPU_PUSH_WORD(stack, 0x11111111); \
+		/* R10 */ \
+		CPU_PUSH_WORD(stack, 0x10101010); \
+		/* R9 */ \
+		CPU_PUSH_WORD(stack, 0x09090909); \
+		/* R8 */ \
+		CPU_PUSH_WORD(stack, 0x08080808); \
+		/* R7 */ \
+		CPU_PUSH_WORD(stack, 0x07070707); \
+		/* R6 */ \
+		CPU_PUSH_WORD(stack, 0x06060606); \
+		/* R5 */ \
+		CPU_PUSH_WORD(stack, 0x05050505); \
+		/* R4 */ \
+		CPU_PUSH_WORD(stack, 0x04040404); \
+		/* CPSR */ \
+		CPU_PUSH_WORD(stack, 0x00000013); \
+	} while (0)
 
 #elif CPU_PPC
 
@@ -244,4 +257,21 @@
 	#endif /* !ARCH_EMUL */
 #endif /* !CPU_IDLE */
 
+/**
+ * Default macro for creating a new Process stack
+ */ 
+#ifndef CPU_CREATE_NEW_STACK
+
+	#define CPU_CREATE_NEW_STACK(stack, entry, exit) \
+		do { \
+			size_t i; \
+			/* Initialize process stack frame */ \
+			CPU_PUSH_CALL_FRAME(stack, exit); \
+			CPU_PUSH_CALL_FRAME(stack, entry); \
+			/* Push a clean set of CPU registers for asm_switch_context() */ \
+			for (i = 0; i < CPU_SAVED_REGS_CNT; i++) \
+				CPU_PUSH_WORD(stack, CPU_REG_INIT_VALUE(i)); \
+		} while (0)
+#endif
+
 #endif /* CPU_ATTR_H */
diff --git a/bertos/kern/proc.c b/bertos/kern/proc.c
index 267ace6c..15fe5b7f 100644
--- a/bertos/kern/proc.c
+++ b/bertos/kern/proc.c
@@ -240,17 +240,9 @@ struct Process *proc_new_with_name(UNUSED_ARG(const char *, name), void (*entry)
 		makecontext(&proc->context, (void (*)(void))proc_entry, 1, entry);
 
 	#else // !CONFIG_KERN_PREEMPT
-	{
-		size_t i;
-
-		/* Initialize process stack frame */
-		CPU_PUSH_CALL_FRAME(proc->stack, proc_exit);
-		CPU_PUSH_CALL_FRAME(proc->stack, entry);
-
-		/* Push a clean set of CPU registers for asm_switch_context() */
-		for (i = 0; i < CPU_SAVED_REGS_CNT; i++)
-			CPU_PUSH_WORD(proc->stack, CPU_REG_INIT_VALUE(i));
-	}
+	
+		CPU_CREATE_NEW_STACK(proc->stack, entry, proc_exit);
+		
 	#endif // CONFIG_KERN_PREEMPT
 
 	#if CONFIG_KERN_MONITOR
-- 
2.25.1