Clean up some of the exception handling code in the new MicroBlaze port.

Demo/MicroBlaze_Spartan-6_EthernetLite/SDKProjects/RTOSDemoSource/FreeRTOS_Source/portable/GCC/MicroBlaze/port_exceptions.c

@@ -73,8 +73,8 @@ stacked register values. */
 #define portexR11_STACK_OFFSET	12
 #define portexR12_STACK_OFFSET	13
 #define portexR15_STACK_OFFSET	16
-#define portexR18_STACK_OFFSET  18
-#define portexMSR_STACK_OFFSET	19
+#define portexR18_STACK_OFFSET  19
+#define portexMSR_STACK_OFFSET	20
 #define portexR19_STACK_OFFSET  -1
 
 /* This is defined to equal the size, in bytes, of the stack frame generated by
@@ -90,9 +90,9 @@ exceptions, or the application defined configuration constant
 configINSTALL_EXCEPTION_HANDLERS is not set to 1. */
 #if ( MICROBLAZE_EXCEPTIONS_ENABLED == 1 ) && ( configINSTALL_EXCEPTION_HANDLERS == 1 )
 
-/* These variables are set in the exception entry code, before 
+/* This variable is set in the exception entry code, before
 vPortExceptionHandler is called. */
-unsigned long *pulStackPointerOnFunctionEntry = NULL, ulBTROnFunctionEntry = 0UL;
+unsigned long *pulStackPointerOnFunctionEntry = NULL;
 
 /* This is the structure that is filled with the MicroBlaze context as it
 existed immediately prior to the exception occurrence.  A pointer to this
@@ -159,8 +159,7 @@ extern void *pxCurrentTCB;
 	xRegisterDump.ulR13_read_write_small_data_area = mfgpr( R13 );
 	xRegisterDump.ulR14_return_address_from_interrupt = mfgpr( R14 );
 	xRegisterDump.ulR16_return_address_from_trap = mfgpr( R16 );
-	xRegisterDump.ulR17_return_address_from_some_exceptions = mfgpr( R17 );
-	xRegisterDump.ulR18 = mfgpr( R18 );
+	xRegisterDump.ulR17_return_address_from_exceptions = mfgpr( R17 );
 	xRegisterDump.ulR20 = mfgpr( R20 );
 	xRegisterDump.ulR21 = mfgpr( R21 );
 	xRegisterDump.ulR22 = mfgpr( R22 );
@@ -174,7 +173,6 @@ extern void *pxCurrentTCB;
 	xRegisterDump.ulR30 = mfgpr( R30 );
 	xRegisterDump.ulR31 = mfgpr( R31 );
 	xRegisterDump.ulR1_SP = ( ( unsigned long ) pulStackPointerOnFunctionEntry ) + portexASM_HANDLER_STACK_FRAME_SIZE;
-	xRegisterDump.ulBTR = ulBTROnFunctionEntry;
 	xRegisterDump.ulEAR = mfear();
 	xRegisterDump.ulESR = mfesr();
 	xRegisterDump.ulEDR = mfedr();
@@ -182,7 +180,7 @@ extern void *pxCurrentTCB;
 	/* Move the saved program counter back to the instruction that was executed
 	when the exception occurred.  This is only valid for certain types of
 	exception. */
-	xRegisterDump.ulPC = xRegisterDump.ulR17_return_address_from_some_exceptions - portexINSTRUCTION_SIZE;
+	xRegisterDump.ulPC = xRegisterDump.ulR17_return_address_from_exceptions - portexINSTRUCTION_SIZE;
 
 	#if XPAR_MICROBLAZE_0_USE_FPU == 1
 	{

Demo/MicroBlaze_Spartan-6_EthernetLite/SDKProjects/RTOSDemoSource/FreeRTOS_Source/portable/GCC/MicroBlaze/portasm.S

@@ -115,7 +115,6 @@ back into the caller stack. */
 	.extern ulTaskSwitchRequested
 	.extern vPortExceptionHandler
 	.extern pulStackPointerOnFunctionEntry
-	.extern ulBTROnFunctionEntry
 
 	.global _interrupt_handler
 	.global VPortYieldASM
@@ -350,8 +349,6 @@ vPortExceptionHandlerEntry:
 	/* Take a copy of the stack pointer before vPortExecptionHandler is called,
 	storing its value prior to the function stack frame being created. */
 	swi r1, r0, pulStackPointerOnFunctionEntry
-	mfs r18, RBTR
-	swi r18, r0, ulBTROnFunctionEntry
 	bralid r15, vPortExceptionHandler
 	or r0, r0, r0
 

Demo/MicroBlaze_Spartan-6_EthernetLite/SDKProjects/RTOSDemoSource/FreeRTOS_Source/portable/GCC/MicroBlaze/portmacro.h

@@ -168,7 +168,7 @@ typedef struct PORT_REGISTER_DUMP
 	unsigned long ulR14_return_address_from_interrupt;
 	unsigned long ulR15_return_address_from_subroutine;
 	unsigned long ulR16_return_address_from_trap;
-	unsigned long ulR17_return_address_from_some_exceptions;
+	unsigned long ulR17_return_address_from_exceptions; /* The exception entry code can copy the BTR in here for exceptions that occur in the delay slot of branch instructions. */
 	unsigned long ulR18;
 	unsigned long ulR19;
 	unsigned long ulR20;
@@ -185,7 +185,6 @@ typedef struct PORT_REGISTER_DUMP
 	unsigned long ulR31;
 	unsigned long ulPC;
 	unsigned long ulESR;
-	unsigned long ulBTR;
 	unsigned long ulMSR;
 	unsigned long ulEAR;
 	unsigned long ulFSR;

Demo/MicroBlaze_Spartan-6_EthernetLite/SDKProjects/RTOSDemoSource/main-full.c

@@ -102,6 +102,7 @@
 
 /* BSP includes. */
 #include "xtmrctr.h"
+#include "microblaze_exceptions_g.h"
 
 /* Kernel includes. */
 #include "FreeRTOS.h"