Add configUSE_TASK_FPU_SUPPORT to AARCH64 port

portable/GCC/ARM_AARCH64/port.c

@@ -133,6 +133,10 @@
 #define portMAX_8_BIT_VALUE                       ( ( uint8_t ) 0xff )
 #define portBIT_0_SET                             ( ( uint8_t ) 0x01 )
 
+/* The space on the stack required to hold the FPU registers.
+ * There are 32 128-bit registers.*/
+#define portFPU_REGISTER_WORDS     ( 32 * 2 )
+
 /*-----------------------------------------------------------*/
 
 /*
@@ -244,23 +248,47 @@ StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack,
     *pxTopOfStack = ( StackType_t ) 0x00;         /* XZR - has no effect, used so there are an even number of registers. */
     pxTopOfStack--;
     *pxTopOfStack = ( StackType_t ) 0x00;         /* R30 - procedure call link register. */
-    pxTopOfStack--;
 
-    *pxTopOfStack = portINITIAL_PSTATE;
-    pxTopOfStack--;
-
-    *pxTopOfStack = ( StackType_t ) pxCode; /* Exception return address. */
     pxTopOfStack--;
+    *pxTopOfStack = portINITIAL_PSTATE;
 
-    /* The task will start with a critical nesting count of 0 as interrupts are
-     * enabled. */
-    *pxTopOfStack = portNO_CRITICAL_NESTING;
     pxTopOfStack--;
+    *pxTopOfStack = ( StackType_t ) pxCode; /* Exception return address. */
 
-    /* The task will start without a floating point context.  A task that uses
-     * the floating point hardware must call vPortTaskUsesFPU() before executing
-     * any floating point instructions. */
-    *pxTopOfStack = portNO_FLOATING_POINT_CONTEXT;
+    #if ( configUSE_TASK_FPU_SUPPORT == 1 )
+    {
+        /* The task will start with a critical nesting count of 0 as interrupts are
+        * enabled. */
+        pxTopOfStack--;
+        *pxTopOfStack = portNO_CRITICAL_NESTING;
+
+        /* The task will start without a floating point context.  A task that
+         * uses the floating point hardware must call vPortTaskUsesFPU() before
+         * executing any floating point instructions. */
+        pxTopOfStack--;
+        *pxTopOfStack = portNO_FLOATING_POINT_CONTEXT;
+    }
+    #elif ( configUSE_TASK_FPU_SUPPORT == 2 )
+    {
+        /* The task will start with a floating point context.  Leave enough
+         * space for the registers - and ensure they are initialised to 0. */
+        pxTopOfStack -= portFPU_REGISTER_WORDS;
+        memset( pxTopOfStack, 0x00, portFPU_REGISTER_WORDS * sizeof( StackType_t ) );
+
+        /* The task will start with a critical nesting count of 0 as interrupts are
+        * enabled. */
+        pxTopOfStack--;
+        *pxTopOfStack = portNO_CRITICAL_NESTING;
+
+        pxTopOfStack--;
+        *pxTopOfStack = pdTRUE;
+        ullPortTaskHasFPUContext = pdTRUE;
+    }
+    #else /* if ( configUSE_TASK_FPU_SUPPORT == 1 ) */
+    {
+        #error "Invalid configUSE_TASK_FPU_SUPPORT setting - configUSE_TASK_FPU_SUPPORT must be set to 1, 2, or left undefined."
+    }
+    #endif /* if ( configUSE_TASK_FPU_SUPPORT == 1 ) */
 
     return pxTopOfStack;
 }