further ATmegaxxxx port alignment

Author: feilipu

library.properties

@@ -1,5 +1,5 @@
 name=FreeRTOS
-version=10.3.0-7
+version=10.3.0-8
 author=Richard Barry <[email protected]>
 maintainer=Phillip Stevens <[email protected]>
 sentence=<h3>FreeRTOS Real Time Operating System implemented for AVR (Uno, Nano, Leonardo, Mega).</h3>

readme.md

@@ -66,7 +66,7 @@ Testing with the Software Serial library shows some incompatibilities at low bau
   * ATmega2560 @ 16MHz : Arduino Mega, Arduino ADK
   * ATmega2560 @ 16MHz : Seeed Studio ADK
 
-The new megaAVR 0-Series devices are not compatible with this library. They are not yet supported by avr-libc and their interrupt structure is substantially different to previous devices. It may be a while until the avr-libc is updated, but when that happens further support can be added.
+The new megaAVR 0-Series devices (eg. ATmega4809) are not fully compatible with this library. Their Timer configuration and structure is substantially different from previous devices, and forms part of a new __avr8x__ architecture. It may be a while until avr-libc is updated to include support, but when that happens further workd can be added here.
 
 ## Files & Configuration
 

src/port.c

@@ -27,6 +27,8 @@
 
 
 #include <stdlib.h>
+
+#include <avr/io.h>
 #include <avr/interrupt.h>
 #include <avr/sleep.h>
 #include <avr/wdt.h>
@@ -380,17 +382,6 @@ static void prvSetupTimerInterrupt( void );
 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
 {
 uint16_t usAddress;
-
-    /* Place a few bytes of known values on the bottom of the stack.
-    This is just useful for debugging. */
-
-    *pxTopOfStack = 0x11;
-    pxTopOfStack--;
-    *pxTopOfStack = 0x22;
-    pxTopOfStack--;
-    *pxTopOfStack = 0x33;
-    pxTopOfStack--;
-
     /* Simulate how the stack would look after a call to vPortYield() generated by
     the compiler. */
 
@@ -415,7 +406,6 @@ uint16_t usAddress;
      * In order to do this properly, we would need to get a full 3-byte pointer to
      * pxCode. That requires a change to GCC. Not likely to happen any time soon.
      */
-
     *pxTopOfStack = 0;
     pxTopOfStack--;
 #endif
@@ -447,51 +437,9 @@ uint16_t usAddress;
 
     /* Now the remaining registers. The compiler expects R1 to be 0. */
     *pxTopOfStack = ( StackType_t ) 0x00;    /* R1 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x02;    /* R2 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x03;    /* R3 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x04;    /* R4 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x05;    /* R5 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x06;    /* R6 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x07;    /* R7 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x08;    /* R8 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x09;    /* R9 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x10;    /* R10 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x11;    /* R11 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x12;    /* R12 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x13;    /* R13 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x14;    /* R14 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x15;    /* R15 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x16;    /* R16 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x17;    /* R17 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x18;    /* R18 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x19;    /* R19 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x20;    /* R20 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x21;    /* R21 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x22;    /* R22 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x23;    /* R23 */
-    pxTopOfStack--;
+
+    /* Leave R2 - R23 untouched */
+    pxTopOfStack -= 23;
 
     /* Place the parameter on the stack in the expected location. */
     usAddress = ( uint16_t ) pvParameters;
@@ -500,20 +448,9 @@ uint16_t usAddress;
 
     usAddress >>= 8;
     *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff );
-    pxTopOfStack--;
 
-    *pxTopOfStack = ( StackType_t ) 0x26;    /* R26 X */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x27;    /* R27 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x28;    /* R28 Y */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x29;    /* R29 */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x30;    /* R30 Z */
-    pxTopOfStack--;
-    *pxTopOfStack = ( StackType_t ) 0x031;   /* R31 */
-    pxTopOfStack--;
+    /* Leave register R26 - R31 untouched */
+    pxTopOfStack -= 7;
 
     return pxTopOfStack;
 }
@@ -560,6 +497,21 @@ void vPortYield( void )
 }
 /*-----------------------------------------------------------*/
 
+/*
+ * Manual context switch callable from ISRs. The first thing we do is save
+ * the registers so we can use a naked attribute.
+ */
+void vPortYieldFromISR(void) __attribute__ ( ( hot, flatten, naked ) );
+void vPortYieldFromISR(void)
+{
+    portSAVE_CONTEXT();
+    vTaskSwitchContext();
+    portRESTORE_CONTEXT();
+
+    __asm__ __volatile__ ( "reti" );
+}
+/*-----------------------------------------------------------*/
+
 /*
  * Context switch function used by the tick. This must be identical to
  * vPortYield() from the call to vTaskSwitchContext() onwards. The only
@@ -577,7 +529,7 @@ void vPortYieldFromTick( void )
     }
     portRESTORE_CONTEXT();
 
-    __asm__ __volatile__ ( "ret" );
+    __asm__ __volatile__ ( "reti" );
 }
 /*-----------------------------------------------------------*/
 
@@ -610,7 +562,6 @@ void prvSetupTimerInterrupt( void )
     ISR(portSCHEDULER_ISR)
     {
         vPortYieldFromTick();
-        __asm__ __volatile__ ( "reti" );
     }
 #else
 
@@ -629,3 +580,4 @@ void prvSetupTimerInterrupt( void )
         xTaskIncrementTick();
     }
 #endif
+