Add ulReadValueAPSR API

Author: kar-rahul-aws

portable/GCC/ARM_CRx_No_GIC/port.c

@@ -83,10 +83,12 @@
 /*-----------------------------------------------------------*/
 
 /*
- * Starts the first task executing.  This function is necessarily written in
+ * Starts the first task executing.  These functions are necessarily written in
  * assembly code so is implemented in portASM.s.
  */
 extern void vPortRestoreTaskContext( void );
+extern void vPortInitialiseFPSCR( void );
+extern uint32_t ulReadValueAPSR( void );
 
 /*
  * Used to catch tasks that attempt to return from their implementing function.
@@ -218,7 +220,7 @@ BaseType_t xPortStartScheduler( void )
 
     /* Only continue if the CPU is not in User mode.  The CPU must be in a
      * Privileged mode for the scheduler to start. */
-    __asm volatile ( "MRS %0, APSR" : "=r" ( ulAPSR )::"memory" );
+    ulAPSR = ulReadValueAPSR();
 
     ulAPSR &= portAPSR_MODE_BITS_MASK;
     configASSERT( ulAPSR != portAPSR_USER_MODE );
@@ -312,14 +314,11 @@ void FreeRTOS_Tick_Handler( void )
 
 void vPortTaskUsesFPU( void )
 {
-    //uint32_t ulInitialFPSCR = 0;
-
     /* A task is registering the fact that it needs an FPU context.  Set the
      * FPU flag (which is saved as part of the task context). */
     ulPortTaskHasFPUContext = pdTRUE;
 
     /* Initialise the floating point status register. */
     vPortInitialiseFPSCR();
-    /*__asm volatile ( "FMXR  FPSCR, %0" ::"r" ( ulInitialFPSCR ) : "memory" );*/
 }
 /*-----------------------------------------------------------*/

portable/GCC/ARM_CRx_No_GIC/portASM.S

@@ -48,6 +48,7 @@
     .global FreeRTOS_SVC_Handler
     .global vPortRestoreTaskContext
     .global vPortInitialiseFPSCR
+    .global ulReadValueAPSR
 
 
 .macro portSAVE_CONTEXT
@@ -162,6 +163,15 @@ vPortInitialiseFPSCR:
     FMXR    FPSCR, R0
     BX      LR
 
+/******************************************************************************
+ * ulReadValueAPSR is used to read the value of APSR context.
+ *****************************************************************************/
+.align 4
+.type ulReadValueAPSR, %function
+ulReadValueAPSR:
+    MRS R0, APSR
+    BX LR
+
 .align 4
 .type FreeRTOS_IRQ_Handler, %function
 FreeRTOS_IRQ_Handler: