Tidy up and comment.

git-svn-id: https://freertos.svn.sourceforge.net/svnroot/freertos/trunk@674 1d2547de-c912-0410-9cb9-b8ca96c0e9e2

3 files changed, 64 insertions, 72 deletions

diff --git a/Source/portable/IAR/78K0R/ISR_Support.h b/Source/portable/IAR/78K0R/ISR_Support.h
index 6b291cc9..126d738b 100644
--- a/Source/portable/IAR/78K0R/ISR_Support.h
+++ b/Source/portable/IAR/78K0R/ISR_Support.h
@@ -39,29 +39,28 @@
 

 ;------------------------------------------------------------------------------

 ;   portSAVE_CONTEXT MACRO

-;   Saves the context of the remaining general purpose registers, CS and ES

-;   (only in far memory mode) registers

-;   the usCriticalNesting Value and the Stack Pointer

+;   Saves the context of the general purpose registers, CS and ES (only in far 

+;	memory mode) registers the usCriticalNesting Value and the Stack Pointer

 ;   of the active Task onto the task stack

 ;------------------------------------------------------------------------------

 portSAVE_CONTEXT MACRO

 

-	PUSH      AX                    ; save AX Register to stack

+	PUSH      AX                    ; Save AX Register to stack.

 	PUSH      HL

 #if configMEMORY_MODE == 1

-	MOV       A, CS                 ; save CS register

+	MOV       A, CS                 ; Save CS register.

 	XCH       A, X

-	MOV       A, ES                 ; save ES register

+	MOV       A, ES                 ; Save ES register.

 	PUSH      AX

 #else

-	MOV       A, CS                 ; save CS register

+	MOV       A, CS                 ; Save CS register.

 	PUSH      AX

 #endif

-	PUSH      DE                    ; save the  remaining general purpose registers

+	PUSH      DE                    ; Save the remaining general purpose registers.

 	PUSH      BC

-	MOVW      AX, usCriticalNesting ; save the usCriticalNesting value	

+	MOVW      AX, usCriticalNesting ; Save the usCriticalNesting value.

 	PUSH      AX	

-	MOVW      AX, pxCurrentTCB 	    ; save the Stack pointer	

+	MOVW      AX, pxCurrentTCB 	    ; Save the Stack pointer.

 	MOVW      HL, AX					

 	MOVW      AX, SP					

 	MOVW      [HL], AX					

@@ -70,30 +69,29 @@ portSAVE_CONTEXT MACRO
 

 ;------------------------------------------------------------------------------

 ;   portRESTORE_CONTEXT MACRO

-;   Restores the context of the Stack Pointer, usCriticalNesting

-;   value, general purpose registers and the CS and ES (only in far memory mode)

+;   Restores the task Stack Pointer then use this to restore usCriticalNesting,

+;   general purpose registers and the CS and ES (only in far memory mode)

 ;   of the selected task from the task stack

 ;------------------------------------------------------------------------------

-

 portRESTORE_CONTEXT MACRO

-	MOVW      AX, pxCurrentTCB	    ; restore the Stack pointer

+	MOVW      AX, pxCurrentTCB	    ; Restore the Stack pointer.

 	MOVW      HL, AX

 	MOVW      AX, [HL]

 	MOVW      SP, AX

-	POP	      AX	            ; restore usCriticalNesting value

+	POP	      AX	                ; Restore usCriticalNesting value.

 	MOVW      usCriticalNesting, AX

-	POP	      BC                    ; restore the necessary general purpose registers

+	POP	      BC                    ; Restore the necessary general purpose registers.

 	POP	      DE

 #if configMEMORY_MODE == 1

-	POP       AX                    ; restore the ES register

+	POP       AX                    ; Restore the ES register.

 	MOV       ES, A

-	XCH       A, X                  ; restore the CS register

+	XCH       A, X                  ; Restore the CS register.

 	MOV       CS, A

 #else

 	POP       AX

-	MOV       CS, A                 ; restore CS register

+	MOV       CS, A                 ; Restore CS register.

 #endif

-	POP       HL                    ; restore general purpose register HL

-	POP       AX                    ; restore AX	

+	POP       HL                    ; Restore general purpose register HL.

+	POP       AX                    ; Restore AX.

 	ENDM

 ;------------------------------------------------------------------------------

diff --git a/Source/portable/IAR/78K0R/port.c b/Source/portable/IAR/78K0R/port.c
index 73658f8a..a14c2e51 100644
--- a/Source/portable/IAR/78K0R/port.c
+++ b/Source/portable/IAR/78K0R/port.c
@@ -54,20 +54,22 @@
 #include "FreeRTOS.h"

 #include "task.h"

 

+/* The critical nesting value is initialised to a non zero value to ensure

+interrupts don't accidentally become enabled before the scheduler is started. */

 #define portINITIAL_CRITICAL_NESTING  (( unsigned portSHORT ) 10)

 

-/* default Initialization of the PSW for the task:

+/* Initial PSW value allocated to a newly created task.

  *   1100011000000000

  *   ||||||||-------------- Fill byte

- *   |||||||--------------- Cary Flag cleared

+ *   |||||||--------------- Carry Flag cleared

  *   |||||----------------- In-service priority Flags set to low level

  *   ||||------------------ Register bank Select 0 Flag cleared

- *   |||------------------- Auxiliary Cary Flag cleared

+ *   |||------------------- Auxiliary Carry Flag cleared

  *   ||-------------------- Register bank Select 1 Flag cleared

  *   |--------------------- Zero Flag set

  *   ---------------------- Global Interrupt Flag set (enabled)

  */

-#define portPSW		  (0xc6000000UL)

+#define portPSW		  (0xc6UL)

 

 /* We require the address of the pxCurrentTCB variable, but don't want to know

 any details of its type. */

@@ -112,36 +114,39 @@ unsigned long *pulLocal;
 

 	#if configMEMORY_MODE == 1

 	{

-		/* Parameters are passed in on the stack. */

+		/* Parameters are passed in on the stack, and written using a 32bit value

+		hence a space is left for the second two bytes. */

 		pxTopOfStack--;

+

+		/* Write in the parameter value. */

 		pulLocal =  ( unsigned long * ) pxTopOfStack;

 		*pulLocal = ( unsigned long ) pvParameters;

 		pxTopOfStack--;

 

-		/* Dummy values on the stack because there normaly the return address

-		of the funtion is written. */

+		/* These values are just spacers.  The return address of the function

+		would normally be written here. */

 		*pxTopOfStack = ( portSTACK_TYPE ) 0xcdcd;

 		pxTopOfStack--;

 		*pxTopOfStack = ( portSTACK_TYPE ) 0xcdcd;

 		pxTopOfStack--;

 

-		/* Initial PSW value. */

-//		*pxTopOfStack = portPSW;

-		

+		/* The start address / PSW value is also written in as a 32bit value,

+		so leave a space for the second two bytes. */

 		pxTopOfStack--;

-

 	

-		/* Task function start address. */

+		/* Task function start address combined with the PSW. */

 		pulLocal = ( unsigned long * ) pxTopOfStack;

-		*pulLocal = ( ( ( unsigned long ) pxCode ) | portPSW );

+		*pulLocal = ( ( ( unsigned long ) pxCode ) | ( portPSW << 24UL ) );

 		pxTopOfStack--;

 

-		/* Next general purpose register AX. */

+		/* An initial value for the AX register. */

 		*pxTopOfStack = ( portSTACK_TYPE ) 0x1111;

 		pxTopOfStack--;

 	}

 	#else

 	{

+		TBD

+

 		pxTopOfStack--;

 

 		/* Task function start address. */

@@ -159,7 +164,7 @@ unsigned long *pulLocal;
 	}

 	#endif

 

-	/* HL. */

+	/* An initial value for the HL register. */

 	*pxTopOfStack = ( portSTACK_TYPE ) 0x2222;

 	pxTopOfStack--;

 

@@ -172,12 +177,13 @@ unsigned long *pulLocal;
 	pxTopOfStack--;

 	*pxTopOfStack = ( portSTACK_TYPE ) 0xBCBC;

 	pxTopOfStack--;

+

+	/* Finally the critical section nesting count is set to zero when the task

+	first starts. */

 	*pxTopOfStack = ( portSTACK_TYPE ) portNO_CRITICAL_SECTION_NESTING;	

 

-	/*

-	 * Return a pointer to the top of the stack we have generated so this can

-	 * be stored in the task control block for the task.

-	 */

+	/* Return a pointer to the top of the stack we have generated so this can

+	be stored in the task control block for the task. */

 	return pxTopOfStack;

 }

 /*-----------------------------------------------------------*/

@@ -198,17 +204,15 @@ portBASE_TYPE xPortStartScheduler( void )
 

 void vPortEndScheduler( void )

 {

-	/* It is unlikely that the 78K0R/Kx3 port will get stopped.  If required simply

+	/* It is unlikely that the 78K0R port will get stopped.  If required simply

 	disable the tick interrupt here. */

 }

 /*-----------------------------------------------------------*/

 

-/*

- * Hardware initialisation to generate the RTOS tick.  This uses Channel 5 of

- * the Timer Array Unit (TAU). Any other Channel could also be used.

- */

 static void prvSetupTimerInterrupt( void )

 {

+	/* Setup channel 5 of the TAU to generate the tick interrupt. */

+

 	/* First the Timer Array Unit has to be enabled. */

 	TAU0EN = 1;

 

diff --git a/Source/portable/IAR/78K0R/portasm.s26 b/Source/portable/IAR/78K0R/portasm.s26
index 2bb46e1c..a2ba1892 100644
--- a/Source/portable/IAR/78K0R/portasm.s26
+++ b/Source/portable/IAR/78K0R/portasm.s26
@@ -41,7 +41,6 @@
 

 ; Functions implemented in this file

 ;------------------------------------------------------------------------------

-

 	PUBLIC    vPortYield

 	PUBLIC    vPortStart

 

@@ -63,7 +62,9 @@ MD_INTTM05    SYMBOL "MD_INTTM05"
 

 

 ;------------------------------------------------------------------------------

-;   Port Yield function to check for a Task switch in the cooperative mode

+;   Yield to another task.  Implemented as a software interrupt.  The return

+;   address and PSW will have been saved to the stack automatically before

+;   this code runs.

 ;

 ;   Input:  NONE

 ;

@@ -75,9 +76,9 @@ MD_INTTM05    SYMBOL "MD_INTTM05"
     RSEG CODE:CODE

 vPortYield:

 	portSAVE_CONTEXT		        ; Save the context of the current task.

-	call      vTaskSwitchContext    ; Call the scheduler.

-	portRESTORE_CONTEXT		        ; Restore the context of whichever task the ...

-	RETB

+	call      vTaskSwitchContext    ; Call the scheduler to select the next task.

+	portRESTORE_CONTEXT		        ; Restore the context of the next task to run.

+	retb

 

 	

 ;------------------------------------------------------------------------------

@@ -93,8 +94,8 @@ vPortYield:
     RSEG CODE:CODE

 vPortStart:

 	portRESTORE_CONTEXT	            ; Restore the context of whichever task the ...

-;	POP       PSW                   ; restore active task PSW

-	reti					            ; ... scheduler decided should run.

+	reti					        ; An interrupt stack frame is used so the task

+                                    ; is started using a RETI instruction.

 

 ;------------------------------------------------------------------------------

 ;   Perform the necessary steps of the Tick Count Increment and Task Switch

@@ -107,42 +108,31 @@ vPortStart:
 ;   Output: NONE

 ;

 ;------------------------------------------------------------------------------	

-#if configUSE_PREEMPTION == 1

 

 MD_INTTM05:

 

 	portSAVE_CONTEXT		        ; Save the context of the current task.

 	call      vTaskIncrementTick    ; Call the timer tick function.

-	call      vTaskSwitchContext    ; Call the scheduler.

-	portRESTORE_CONTEXT		        ; Restore the context of whichever task the ...

-	RETI

-#else

-

-MD_INTTM05:

-	PUSH        AX                  ; save necessary general purpose register...

-	PUSH        HL                  ; ...used by the ISR

-	MOVW        AX, CS              ; save CS register

-	PUSH        AX

-	CALL        vTaskIncrementTick  ; Call the timer tick function.

-	POP         AX

-	MOVW        CS, AX              ; restore CS register

-	POP         HL                  ; restore used general purpose registers

-	POP         AX

-	RETI

+#if configUSE_PREEMPTION == 1

+	call      vTaskSwitchContext    ; Call the scheduler to select the next task.

 #endif

+	portRESTORE_CONTEXT		        ; Restore the context of the next task to run.

+	reti

+

+

 

 	REQUIRE ?CL78K0R_V2_L00

-	COMMON INTVEC:CODE:ROOT(1)      ; set ISR location to the Interrupt vector table

+	COMMON INTVEC:CODE:ROOT(1)      ; Set ISR location to the Interrupt vector table.

 	ORG 68

 `??MD_INTTM05??INTVEC 68`:

 	DW MD_INTTM05

 

-	COMMON INTVEC:CODE:ROOT(1)      ; set ISR location to the Interrupt vector table

+	COMMON INTVEC:CODE:ROOT(1)      ; Set ISR location to the Interrupt vector table.

 	ORG 126

 `??vPortYield??INTVEC 126`:

 	DW vPortYield

 

-									; set value for the usCriticalNesting

+									; Set value for the usCriticalNesting.

 	RSEG NEAR_ID:CONST:SORT:NOROOT(1)

 `?<Initializer for usCriticalNesting>`:

 	DW 10