General tidy up of SH files.

[freertos] / Source / portable / Renesas / SH2A_FPU / port.c

diff --git a/Source/portable/Renesas/SH2A_FPU/port.c b/Source/portable/Renesas/SH2A_FPU/port.c
index c52485c8169ae1cb327ded740db0b6dbc23f3e4d..7ce291939c3a14b446ec696741fb274c3db18907 100644 (file)
--- a/Source/portable/Renesas/SH2A_FPU/port.c
+++ b/Source/portable/Renesas/SH2A_FPU/port.c
@@ -62,9 +62,14 @@
 /* Library includes. */\r
 #include "string.h"\r
 \r
-#define portINITIAL_SR                 0UL /* No interrupts masked. */\r
+/*-----------------------------------------------------------*/\r
+\r
+/* The SR assigned to a newly created task.  The only important thing in this\r
+value is for all interrupts to be enabled. */\r
+#define portINITIAL_SR                         ( 0UL )\r
 \r
-/* Allocate enough space for FPR0 to FPR15, FPUL and FPSCR, each of which is 4\r
+/* Dimensions the array into which the floating point context is saved.  \r
+Allocate enough space for FPR0 to FPR15, FPUL and FPSCR, each of which is 4\r
 bytes big.  If this number is changed then the 72 in portasm.src also needs\r
 changing. */\r
 #define portFLOP_REGISTERS_TO_STORE    ( 18 )\r
@@ -72,11 +77,6 @@ changing. */
 \r
 /*-----------------------------------------------------------*/\r
 \r
-/*\r
- * Setup a peripheral timer to generate the RTOS tick interrupt.\r
- */\r
-static void prvSetupTimerInterrupt( void );\r
-\r
 /*\r
  * The TRAPA handler used to force a context switch.\r
  */\r
@@ -200,10 +200,18 @@ pxTopOfStack--;
 \r
 portBASE_TYPE xPortStartScheduler( void )\r
 {\r
-       /* Start the tick interrupt. */\r
-       prvSetupTimerInterrupt();\r
-       \r
-       /* Start the first task. */\r
+extern void vApplicationSetupTimerInterrupt( void );\r
+\r
+       /* Call an application function to set up the timer that will generate the\r
+       tick interrupt.  This way the application can decide which peripheral to \r
+       use.  A demo application is provided to show a suitable example. */\r
+       vApplicationSetupTimerInterrupt();\r
+\r
+       /* Start the first task.  This will only restore the standard registers and\r
+       not the flop registers.  This does not really matter though because the only\r
+       flop register that is initialised to a particular value is fpscr, and it is\r
+       only initialised to the current value, which will still be the current value\r
+       when the first task starts executing. */\r
        trapa( portSTART_SCHEDULER_TRAP_NO );\r
 \r
        /* Should not get here. */\r
@@ -217,30 +225,12 @@ void vPortEndScheduler( void )
 }\r
 /*-----------------------------------------------------------*/\r
 \r
-void vPortTickInterrupt( void )\r
-{\r
-       vTaskIncrementTick();\r
-       #if configUSE_PREEMPTION == 1\r
-               vTaskSwitchContext();\r
-       #endif\r
-}\r
-/*-----------------------------------------------------------*/\r
-\r
-static void prvSetupTimerInterrupt( void )\r
-{\r
-extern void vApplicationSetupTimerInterrupt( void );\r
-\r
-       /* Call an application function to set up the timer.  This way the application\r
-       can decide which peripheral to use.  A demo application is provided to show a\r
-       suitable example. */\r
-       vApplicationSetupTimerInterrupt();\r
-}\r
-/*-----------------------------------------------------------*/\r
-\r
 void vPortYield( void )\r
 {\r
 long lInterruptMask;\r
 \r
+       /* Ensure the yield trap runs at the same priority as the other interrupts\r
+       that can cause a context switch. */\r
        lInterruptMask = get_imask();\r
 \r
        /* taskYIELD() can only be called from a task, not an interrupt, so the\r
@@ -250,6 +240,8 @@ long lInterruptMask;
        \r
        trapa( portYIELD_TRAP_NO );\r
        \r
+       /* Restore the interrupt mask to whatever it was previously (when the\r
+       function was entered. */\r
        set_imask( ( int ) lInterruptMask );\r
 }\r
 /*-----------------------------------------------------------*/\r
@@ -260,9 +252,15 @@ unsigned long *pulFlopBuffer;
 portBASE_TYPE xReturn;\r
 extern void * volatile pxCurrentTCB;\r
 \r
+       /* This function tells the kernel that the task referenced by xTask is\r
+       going to use the floating point registers and therefore requires the\r
+       floating point registers saved as part of its context. */\r
+\r
+       /* Passing NULL as xTask is used to indicate that the calling task is the\r
+       subject task - so pxCurrentTCB is the task handle. */\r
        if( xTask == NULL )\r
        {\r
-               xTask = pxCurrentTCB;\r
+               xTask = ( xTaskHandle ) pxCurrentTCB;\r
        }\r
 \r
        /* Allocate a buffer large enough to hold all the flop registers. */\r
@@ -270,12 +268,15 @@ extern void * volatile pxCurrentTCB;
        \r
        if( pulFlopBuffer != NULL )\r
        {\r
+               /* Start with the registers in a benign state. */\r
                memset( ( void * ) pulFlopBuffer, 0x00, portFLOP_STORAGE_SIZE );\r
                \r
+               /* The first thing to get saved in the buffer is the FPSCR value -\r
+               initialise this to the current FPSCR value. */\r
                *pulFlopBuffer = get_fpscr();\r
                \r
-               /* Use the task tag to point to the flop buffer.  Pass pointer to just above\r
-               the buffer because the flop save routine uses a pre-decrement. */\r
+               /* Use the task tag to point to the flop buffer.  Pass pointer to just \r
+               above the buffer because the flop save routine uses a pre-decrement. */\r
                vTaskSetApplicationTaskTag( xTask, ( void * ) ( pulFlopBuffer + portFLOP_REGISTERS_TO_STORE ) );                \r
                xReturn = pdPASS;\r
        }\r