From bb365559cbe2ac3feb9c90e79a8fce01e05e231c Mon Sep 17 00:00:00 2001
From: richardbarry <richardbarry@1d2547de-c912-0410-9cb9-b8ca96c0e9e2>
Date: Wed, 29 Dec 2010 18:46:02 +0000
Subject: [PATCH] Tidy up the port layer for the MSP430X IAR port - still a
 work in progress.

git-svn-id: https://svn.code.sf.net/p/freertos/code/trunk@1190 1d2547de-c912-0410-9cb9-b8ca96c0e9e2
---
 Source/portable/IAR/MSP430X/port.c      | 25 +------------------------
 Source/portable/IAR/MSP430X/portext.s43 | 25 +++++++------------------
 2 files changed, 8 insertions(+), 42 deletions(-)

diff --git a/Source/portable/IAR/MSP430X/port.c b/Source/portable/IAR/MSP430X/port.c
index 669561cb6..5c44aa113 100644
--- a/Source/portable/IAR/MSP430X/port.c
+++ b/Source/portable/IAR/MSP430X/port.c
@@ -97,8 +97,6 @@ void vPortSetupTimerInterrupt( void );
  */
 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
 {
-unsigned short usNibble;
-unsigned long ulSP_PC_Combined;
 unsigned short *pusTopOfStack;
 
 	/*
@@ -113,30 +111,13 @@ unsigned short *pusTopOfStack;
 		pxTopOfStack--;
 	*/
 
-	/* The msp430x automatically pushes the PC then SR onto the stack before
-	executing an ISR.  We want the stack to look just as if this has happened
-	so place a pointer to the start of the task on the stack first - followed
-	by the flags we want the task to use when it starts up. */
-	
-	/* When placed on the stack, the top four bits of the status register
-	contain bits 19:16 of the 20 bit return address (pxCode). */
-#ifdef GENERATE_ISR_STACK_FRAME
-	usNibble = ( unsigned short ) ( ( ( unsigned long ) pxCode >> 15UL ) & 0x0fUL );
-
-	ulSP_PC_Combined = ( unsigned long ) pxCode;
-	ulSP_PC_Combined <<= 16;
-	ulSP_PC_Combined |= ( usNibble << 12 );
-	ulSP_PC_Combined |= portFLAGS_INT_ENABLED;
-	*pxTopOfStack = ulSP_PC_Combined;
-	pxTopOfStack--;
-#else
 	*pxTopOfStack = ( portSTACK_TYPE ) pxCode;
 	pusTopOfStack = ( unsigned short * ) pxTopOfStack;
 	pusTopOfStack--;
 	*pusTopOfStack = portFLAGS_INT_ENABLED;
 	pusTopOfStack -= 2;
 	pxTopOfStack = ( portSTACK_TYPE * ) pusTopOfStack;
-#endif
+
 	/* Next the general purpose registers. */
 	*pxTopOfStack = ( portSTACK_TYPE ) 0xffffff;
 	pxTopOfStack--;
@@ -154,12 +135,8 @@ unsigned short *pusTopOfStack;
 	pxTopOfStack--;
 	*pxTopOfStack = ( portSTACK_TYPE ) 0x888888;
 	pxTopOfStack--;	
-	
-	/* When the task starts is will expect to find the function parameter in
-	R15. */
 	*pxTopOfStack = ( portSTACK_TYPE ) 0x555555;
 	pxTopOfStack--;
-	
 	*pxTopOfStack = ( portSTACK_TYPE ) 0x666666;
 	pxTopOfStack--;
 	*pxTopOfStack = ( portSTACK_TYPE ) 0x555555;
diff --git a/Source/portable/IAR/MSP430X/portext.s43 b/Source/portable/IAR/MSP430X/portext.s43
index ee2daeb74..fe4e90714 100644
--- a/Source/portable/IAR/MSP430X/portext.s43
+++ b/Source/portable/IAR/MSP430X/portext.s43
@@ -71,8 +71,13 @@
  *
  * If the preemptive scheduler is in use a context switch can also occur.
  */
+	
 	RSEG ISR_CODE
+	
 vTickISR:
+	
+	/* The sr is not saved in portSAVE_CONTEXT() because vPortYield() needs
+	to save it manually before it gets modified (interrupts get disabled). */
 	push.w sr
 	portSAVE_CONTEXT
 				
@@ -92,15 +97,9 @@ vTickISR:
  */
 vPortYield:
 
-	/* 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. */
+	/* The sr needs saving before it is modified. */
 	push.w	sr
+	
 	/* Now the SR is stacked we can disable interrupts. */
 	dint	
 	nop
@@ -130,15 +129,5 @@ xPortStartScheduler:
 	portRESTORE_CONTEXT
 /*-----------------------------------------------------------*/
       		
-
-	/* Install vTickISR as the interrupt on the vector specified by the
-	application code. */
-	/*COMMON INTVEC *./
-	/*ORG 0xFF80 + configTICK_INTERRUPT_VECTOR
-	ORG 0xFFEC
-	
-	__vTickISR__: DC16 0xabcd*/
-	
-
 	END
 		
-- 
2.39.5