Basic cooperative reg test tasks working.

Source/portable/GCC/PPC405/port.c

@@ -162,9 +162,9 @@ portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE
 	pxTopOfStack--;
 	*pxTopOfStack = portINITIAL_MSR;/* SRR1. */
 	pxTopOfStack--;
-	*pxTopOfStack = 0x00000000UL;/* Next LR. */
+	*pxTopOfStack = ( portSTACK_TYPE ) vStartFirstTask;/* Next LR. */
 	pxTopOfStack--;
-	*pxTopOfStack = portINITIAL_MSR;/* Backchain. */
+	*pxTopOfStack = 0x00000000UL;;/* Backchain. */
 //	pxTopOfStack--;
 
 	return pxTopOfStack;

Source/portable/GCC/PPC405/portasm.s

@@ -11,7 +11,7 @@
 .set portGPR_OFFSET, 32
 .set portCR_OFFSET, 28
 .set portXER_OFFSET, 24
-.set portLR_OFFSET, 20
+.set portLR_OFFSET, 16
 .set portCTR_OFFSET, 16
 .set portUSPRG0_OFFSET, 12
 .set portSRR0_OFFSET, 8
@@ -167,10 +167,24 @@
 	# Store the stack pointer into the TCB
 	stw		SP,	0( R2 )
 
+	# Save the link register
+	stwu	R1, -24( R1 )
+	mflr	R0
+	stw		R31, 20( R1 )
+	stw		R0, 28( R1 )
+	mr		R31, r1
+
 .endm
 
 .macro portEXIT_SWITCHING_ISR
 
+	# Restore the link register
+	lwz		R11, 0( R1 )
+	lwz		R0, 4( R11 )
+	mtlr	R0
+	lwz		R31, -4( R11 )
+	mr		R1, R11
+
 	# Get the address of the TCB.
 	xor		R0, R0, R0
 	addis   SP, R0, pxCurrentTCB@ha
@@ -179,11 +193,6 @@
 	# Get the task stack pointer from the TCB.
 	lwz		SP, 0( SP )
 
-	# Load up the LR for the correct return.
-	lwz	R0,LRField(R1)
-	mtlr	R0
-
-
 .endm
 
 

Source/portable/GCC/PPC405/portmacro.h

@@ -90,7 +90,7 @@ void vPortExitCritical( void );
 
 /* Task utilities. */
 void vPortYield( void );
-#define portYIELD() asm volatile ( "SC" )
+#define portYIELD() asm volatile ( "SC \n\t NOP" )
 #define portYIELD_FROM_ISR()
 /*-----------------------------------------------------------*/