From 03e1f298c44ef11e000cfd24d1c45bf5361cbfe3 Mon Sep 17 00:00:00 2001
From: richardbarry <richardbarry@1d2547de-c912-0410-9cb9-b8ca96c0e9e2>
Date: Tue, 28 Dec 2010 18:40:12 +0000
Subject: [PATCH] Continue development of MSP430X port.

git-svn-id: https://svn.code.sf.net/p/freertos/code/trunk@1188 1d2547de-c912-0410-9cb9-b8ca96c0e9e2
---
 Source/portable/IAR/MSP430X/port.c      |  2 +-
 Source/portable/IAR/MSP430X/portasm.h   | 28 ++++++++-----------------
 Source/portable/IAR/MSP430X/portext.s43 | 15 +++++++++----
 3 files changed, 21 insertions(+), 24 deletions(-)

diff --git a/Source/portable/IAR/MSP430X/port.c b/Source/portable/IAR/MSP430X/port.c
index a008016ff..5509599e1 100644
--- a/Source/portable/IAR/MSP430X/port.c
+++ b/Source/portable/IAR/MSP430X/port.c
@@ -143,7 +143,7 @@ unsigned long ulSP_PC_Combined;
 	pxTopOfStack--;
 	*pxTopOfStack = ( portSTACK_TYPE ) 0xdddddd;
 	pxTopOfStack--;
-	*pxTopOfStack = ( portSTACK_TYPE ) 0xcccccc;
+	*pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
 	pxTopOfStack--;
 	*pxTopOfStack = ( portSTACK_TYPE ) 0xbbbbbb;
 	pxTopOfStack--;
diff --git a/Source/portable/IAR/MSP430X/portasm.h b/Source/portable/IAR/MSP430X/portasm.h
index 95b0d5140..9f7c9ca65 100644
--- a/Source/portable/IAR/MSP430X/portasm.h
+++ b/Source/portable/IAR/MSP430X/portasm.h
@@ -54,34 +54,24 @@
 #ifndef PORTASM_H
 #define PORTASM_H
 
-portSAVE_CONTEXT macro
-
 		IMPORT pxCurrentTCB
 		IMPORT usCriticalNesting
 
+portSAVE_CONTEXT macro
+
 		/* Save the remaining registers. */
-		push	r4
-		push	r5
-		push	r6
-		push	r7
-		push	r8
-		push	r9
-		push	r10
-		push	r11
-		push	r12
-		push	r13
-		push	r14
-		push	r15
-		mov.w	&usCriticalNesting, r14
-		push	r14
-		mov.w	&pxCurrentTCB, r12
-		mov.w	r1, 0(r12)
+		pushm.a	#12, r15
+		movx.w	&usCriticalNesting, r14
+		pushx.a r14
+		movx.a	&pxCurrentTCB, r12
+		movx.a	sp, 0( r12 )
 		endm
 /*-----------------------------------------------------------*/
 		
 portRESTORE_CONTEXT macro
+
 		movx.a	&pxCurrentTCB, r12
-		movx.a	@r12, r1
+		movx.a	@r12, sp
 		popx.a	r15
 		movx.w	r15, &usCriticalNesting
 		popm.a	#12, r15
diff --git a/Source/portable/IAR/MSP430X/portext.s43 b/Source/portable/IAR/MSP430X/portext.s43
index a96a81baa..253da1574 100644
--- a/Source/portable/IAR/MSP430X/portext.s43
+++ b/Source/portable/IAR/MSP430X/portext.s43
@@ -90,16 +90,23 @@ vTickISR:
  */
 vPortYield:
 
-	/* Mimic an interrupt by pushing the SR. */
-	push	SR			
+	/* Mimic an interrupt by combining the SR and the PC, the latter having
+	already been pushed onto the stack.  R14 is a scratch registers. */
+	popx.a	r14 		/* r14 will hold the 20 bit PC. */
+	push.w	r14 		/* Push just 16 bits of the 20bit PC back onto the stack. */
+	rram.a	#4, r14 	/* Move the top 4 bits of the PC down ready to be combined with the SP. */
+	and.w	#0xf000, r14/* Ensure other bits are clear. */
+	add.w	sr, r14		/* Combine the top 4 bits of the PC with the SR. */
+	push.w	r14			/* Push the generated combined value onto the stack. */
 
 	/* Now the SR is stacked we can disable interrupts. */
-	dint			
+	dint	
+	nop
 				
 	/* Save the context of the current task. */
 	portSAVE_CONTEXT			
 
-	/* Switch to the highest priority task that is ready to run. */
+	/* Select the next task to run. */
 	calla	#vTaskSwitchContext		
 
 	/* Restore the context of the new task. */
-- 
2.39.5