Added GCC port files for AVR Mega0 and AVR Dx. (#101)
diff --git a/portable/GCC/AVR_AVRDx/port.c b/portable/GCC/AVR_AVRDx/port.c
new file mode 100644
index 0000000..8fca329
--- /dev/null
+++ b/portable/GCC/AVR_AVRDx/port.c
@@ -0,0 +1,350 @@
+/*
+ * FreeRTOS Kernel V10.0.0
+ * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software. If you wish to use our Amazon
+ * FreeRTOS name, please do so in a fair use way that does not cause confusion.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://www.FreeRTOS.org
+ * http://aws.amazon.com/freertos
+ *
+ * 1 tab == 4 spaces!
+ */
+
+#include <stdlib.h>
+
+#include <avr/interrupt.h>
+#include "porthardware.h"
+#include "FreeRTOS.h"
+#include "task.h"
+
+/*-----------------------------------------------------------
+ * Implementation of functions defined in portable.h for the AVR port.
+ *----------------------------------------------------------*/
+
+/* Start tasks with interrupts enables. */
+#define portFLAGS_INT_ENABLED ((StackType_t) 0x80)
+
+/*-----------------------------------------------------------*/
+
+/* We require the address of the pxCurrentTCB variable, but don't want to know
+any details of its type. */
+typedef void RTOS_TCB_t;
+extern volatile RTOS_TCB_t *volatile pxCurrentTCB;
+
+/*-----------------------------------------------------------*/
+
+/*
+ * Macro to save all the general purpose registers, the save the stack pointer
+ * into the TCB.
+ *
+ * The first thing we do is save the flags then disable interrupts. This is to
+ * guard our stack against having a context switch interrupt after we have already
+ * pushed the registers onto the stack - causing the 32 registers to be on the
+ * stack twice.
+ *
+ * r1 is set to zero as the compiler expects it to be thus, however some
+ * of the math routines make use of R1.
+ *
+ * The interrupts will have been disabled during the call to portSAVE_CONTEXT()
+ * so we need not worry about reading/writing to the stack pointer.
+
+ */
+
+#define portSAVE_CONTEXT() \
+ asm volatile("push r0 \n\t" \
+ "in r0, __SREG__ \n\t" \
+ "cli \n\t" \
+ "push r0 \n\t" \
+ "in r0, __RAMPZ__ \n\t" \
+ "push r0 \n\t" \
+ "push r1 \n\t" \
+ "clr r1 \n\t" \
+ "push r2 \n\t" \
+ "push r3 \n\t" \
+ "push r4 \n\t" \
+ "push r5 \n\t" \
+ "push r6 \n\t" \
+ "push r7 \n\t" \
+ "push r8 \n\t" \
+ "push r9 \n\t" \
+ "push r10 \n\t" \
+ "push r11 \n\t" \
+ "push r12 \n\t" \
+ "push r13 \n\t" \
+ "push r14 \n\t" \
+ "push r15 \n\t" \
+ "push r16 \n\t" \
+ "push r17 \n\t" \
+ "push r18 \n\t" \
+ "push r19 \n\t" \
+ "push r20 \n\t" \
+ "push r21 \n\t" \
+ "push r22 \n\t" \
+ "push r23 \n\t" \
+ "push r24 \n\t" \
+ "push r25 \n\t" \
+ "push r26 \n\t" \
+ "push r27 \n\t" \
+ "push r28 \n\t" \
+ "push r29 \n\t" \
+ "push r30 \n\t" \
+ "push r31 \n\t" \
+ "lds r26, pxCurrentTCB \n\t" \
+ "lds r27, pxCurrentTCB + 1 \n\t" \
+ "in r0, __SP_L__ \n\t" \
+ "st x+, r0 \n\t" \
+ "in r0, __SP_H__ \n\t" \
+ "st x+, r0 \n\t");
+
+/*
+ * Opposite to portSAVE_CONTEXT(). Interrupts will have been disabled during
+ * the context save so we can write to the stack pointer.
+ */
+
+#define portRESTORE_CONTEXT() \
+ asm volatile("lds r26, pxCurrentTCB \n\t" \
+ "lds r27, pxCurrentTCB + 1 \n\t" \
+ "ld r28, x+ \n\t" \
+ "out __SP_L__, r28 \n\t" \
+ "ld r29, x+ \n\t" \
+ "out __SP_H__, r29 \n\t" \
+ "pop r31 \n\t" \
+ "pop r30 \n\t" \
+ "pop r29 \n\t" \
+ "pop r28 \n\t" \
+ "pop r27 \n\t" \
+ "pop r26 \n\t" \
+ "pop r25 \n\t" \
+ "pop r24 \n\t" \
+ "pop r23 \n\t" \
+ "pop r22 \n\t" \
+ "pop r21 \n\t" \
+ "pop r20 \n\t" \
+ "pop r19 \n\t" \
+ "pop r18 \n\t" \
+ "pop r17 \n\t" \
+ "pop r16 \n\t" \
+ "pop r15 \n\t" \
+ "pop r14 \n\t" \
+ "pop r13 \n\t" \
+ "pop r12 \n\t" \
+ "pop r11 \n\t" \
+ "pop r10 \n\t" \
+ "pop r9 \n\t" \
+ "pop r8 \n\t" \
+ "pop r7 \n\t" \
+ "pop r6 \n\t" \
+ "pop r5 \n\t" \
+ "pop r4 \n\t" \
+ "pop r3 \n\t" \
+ "pop r2 \n\t" \
+ "pop r1 \n\t" \
+ "pop r0 \n\t" \
+ "out __RAMPZ__, r0 \n\t" \
+ "pop r0 \n\t" \
+ "out __SREG__, r0 \n\t" \
+ "pop r0 \n\t");
+
+/*-----------------------------------------------------------*/
+
+/*
+ * Perform hardware setup to enable ticks from timer.
+ */
+static void prvSetupTimerInterrupt(void);
+/*-----------------------------------------------------------*/
+
+/*
+ * See header file for description.
+ */
+StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters)
+{
+ uint16_t usAddress;
+
+ /*lint -e950 -e611 -e923 Lint doesn't like this much - but nothing I can do about it. */
+
+ /* Place a few bytes of known values on the bottom of the stack.
+ This is just useful for debugging. Uncomment if needed. */
+ // *pxTopOfStack = 0x11;
+ // pxTopOfStack--;
+ // *pxTopOfStack = 0x22;
+ // pxTopOfStack--;
+ // *pxTopOfStack = 0x33;
+ // pxTopOfStack--;
+
+ /* The start of the task code will be popped off the stack last, so place
+ it on first. */
+ usAddress = (uint16_t)pxCode;
+ *pxTopOfStack = (StackType_t)(usAddress & (uint16_t)0x00ff);
+ pxTopOfStack--;
+
+ usAddress >>= 8;
+ *pxTopOfStack = (StackType_t)(usAddress & (uint16_t)0x00ff);
+ pxTopOfStack--;
+
+ /* Next simulate the stack as if after a call to portSAVE_CONTEXT().
+ portSAVE_CONTEXT places the flags on the stack immediately after r0
+ to ensure the interrupts get disabled as soon as possible, and so ensuring
+ the stack use is minimal should a context switch interrupt occur. */
+ *pxTopOfStack = (StackType_t)0x00; /* R0 */
+ pxTopOfStack--;
+ *pxTopOfStack = portFLAGS_INT_ENABLED;
+ pxTopOfStack--;
+ *pxTopOfStack = ( StackType_t ) 0x00; /* RAMPZ */
+ pxTopOfStack--;
+
+ /* Now the remaining registers. The compiler expects R1 to be 0. */
+ *pxTopOfStack = (StackType_t)0x00; /* R1 */
+
+ /* Leave R2 - R23 untouched */
+ pxTopOfStack -= 23;
+
+ /* Place the parameter on the stack in the expected location. */
+ usAddress = (uint16_t)pvParameters;
+ *pxTopOfStack = (StackType_t)(usAddress & (uint16_t)0x00ff);
+ pxTopOfStack--;
+
+ usAddress >>= 8;
+ *pxTopOfStack = (StackType_t)(usAddress & (uint16_t)0x00ff);
+
+ /* Leave register R26 - R31 untouched */
+ pxTopOfStack -= 7;
+
+ /*lint +e950 +e611 +e923 */
+
+ return pxTopOfStack;
+}
+/*-----------------------------------------------------------*/
+
+BaseType_t xPortStartScheduler(void)
+{
+ /* Setup the hardware to generate the tick. */
+ prvSetupTimerInterrupt();
+
+ /* Restore the context of the first task that is going to run. */
+ portRESTORE_CONTEXT();
+
+ /* Simulate a function call end as generated by the compiler. We will now
+ jump to the start of the task the context of which we have just restored. */
+ asm volatile("ret");
+
+ /* Should not get here. */
+ return pdTRUE;
+}
+/*-----------------------------------------------------------*/
+
+void vPortEndScheduler(void)
+{
+ /* vPortEndScheduler is not implemented in this port. */
+}
+/*-----------------------------------------------------------*/
+
+/*
+ * Manual context switch. The first thing we do is save the registers so we
+ * can use a naked attribute.
+ */
+void vPortYield(void) __attribute__((naked));
+void vPortYield(void)
+{
+ portSAVE_CONTEXT();
+ vTaskSwitchContext();
+ portRESTORE_CONTEXT();
+ asm volatile("ret");
+}
+/*-----------------------------------------------------------*/
+
+/*
+ * 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__((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
+ * difference from vPortYield() is the tick count is incremented as the
+ * call comes from the tick ISR.
+ */
+void vPortYieldFromTick(void) __attribute__((naked));
+void vPortYieldFromTick(void)
+{
+ portSAVE_CONTEXT();
+
+ if (xTaskIncrementTick() != pdFALSE) {
+ vTaskSwitchContext();
+ }
+
+ portRESTORE_CONTEXT();
+
+ asm volatile("reti");
+}
+/*-----------------------------------------------------------*/
+
+/*
+ * Setup timer to generate a tick interrupt.
+ */
+static void prvSetupTimerInterrupt(void)
+{
+ TICK_init();
+}
+/*-----------------------------------------------------------*/
+
+#if configUSE_PREEMPTION == 1
+
+/*
+ * Tick ISR for preemptive scheduler. We can use a naked attribute as
+ * the context is saved at the start of vPortYieldFromTick(). The tick
+ * count is incremented after the context is saved.
+ */
+
+ISR(TICK_INT_vect, ISR_NAKED)
+{
+ /* Clear tick interrupt flag. */
+ CLR_INT(INT_FLAGS, INT_MASK);
+
+ vPortYieldFromTick();
+
+ asm volatile("reti");
+}
+
+#else
+
+/*
+ * Tick ISR for the cooperative scheduler. All this does is increment the
+ * tick count. We don't need to switch context, this can only be done by
+ * manual calls to taskYIELD();
+ */
+
+ISR(TICK_INT_vect)
+{
+ /* Clear tick interrupt flag. */
+ INT_FLAGS = INT_MASK;
+
+ xTaskIncrementTick();
+}
+
+
+#endif
diff --git a/portable/GCC/AVR_AVRDx/porthardware.h b/portable/GCC/AVR_AVRDx/porthardware.h
new file mode 100644
index 0000000..4b0e04b
--- /dev/null
+++ b/portable/GCC/AVR_AVRDx/porthardware.h
@@ -0,0 +1,133 @@
+#ifndef PORTHARDWARE_H
+#define PORTHARDWARE_H
+
+#include "FreeRTOSConfig.h"
+
+/*-----------------------------------------------------------*/
+
+#define CLR_INT(FLAG_REG, FLAG_MASK) \
+ asm volatile( "push r16\n\t" \
+ "ldi r16, %1\n\t" \
+ "sts %0, r16\n\t" \
+ "pop r16\n\t" \
+ : \
+ : "i"(_SFR_MEM_ADDR(FLAG_REG)),"i"((uint8_t)(FLAG_MASK)) \
+ );
+
+#if ( configUSE_TIMER_INSTANCE == 0 )
+
+ #define TICK_INT_vect TCB0_INT_vect
+ #define INT_FLAGS TCB0_INTFLAGS
+ #define INT_MASK TCB_CAPT_bm
+
+ #define TICK_init() { \
+ TCB0.CCMP = configCPU_CLOCK_HZ / configTICK_RATE_HZ; \
+ TCB0.INTCTRL = TCB_CAPT_bm; \
+ TCB0.CTRLA = TCB_ENABLE_bm; \
+ }
+
+ #define TICK_stop() { \
+ TCB0.INTCTRL &= ~TCB_CAPT_bm;\
+ TCB0.CTRLA &= ~TCB_ENABLE_bm; \
+ }
+
+#elif ( configUSE_TIMER_INSTANCE == 1 )
+
+ #define TICK_INT_vect TCB1_INT_vect
+ #define INT_FLAGS TCB1_INTFLAGS
+ #define INT_MASK TCB_CAPT_bm
+
+ #define TICK_init() { \
+ TCB1.CCMP = configCPU_CLOCK_HZ / configTICK_RATE_HZ; \
+ TCB1.INTCTRL = TCB_CAPT_bm; \
+ TCB1.CTRLA = TCB_ENABLE_bm; \
+ }
+
+ #define TICK_stop() { \
+ TCB1.INTCTRL &= ~TCB_CAPT_bm; \
+ TCB1.CTRLA &= ~TCB_ENABLE_bm; \
+ }
+
+#elif ( configUSE_TIMER_INSTANCE == 2 )
+
+ #define TICK_INT_vect TCB2_INT_vect
+ #define INT_FLAGS TCB2_INTFLAGS
+ #define INT_MASK TCB_CAPT_bm
+
+ #define TICK_init() { \
+ TCB2.CCMP = configCPU_CLOCK_HZ / configTICK_RATE_HZ; \
+ TCB2.INTCTRL = TCB_CAPT_bm; \
+ TCB2.CTRLA = TCB_ENABLE_bm; \
+ }
+
+ #define TICK_stop() { \
+ TCB2.INTCTRL &= ~TCB_CAPT_bm; \
+ TCB2.CTRLA &= ~TCB_ENABLE_bm; \
+ }
+
+#elif ( configUSE_TIMER_INSTANCE == 3 )
+
+ #define TICK_INT_vect TCB3_INT_vect
+ #define INT_FLAGS TCB3_INTFLAGS
+ #define INT_MASK TCB_CAPT_bm
+
+ #define TICK_init() { \
+ TCB3.CCMP = configCPU_CLOCK_HZ / configTICK_RATE_HZ; \
+ TCB3.INTCTRL = TCB_CAPT_bm; \
+ TCB3.CTRLA = TCB_ENABLE_bm; \
+ }
+
+ #define TICK_stop() { \
+ TCB3.INTCTRL &= ~TCB_CAPT_bm; \
+ TCB3.CTRLA &= ~TCB_ENABLE_bm; \
+ }
+
+#elif ( configUSE_TIMER_INSTANCE == 4 )
+
+ #define TICK_INT_vect TCB4_INT_vect
+ #define INT_FLAGS TCB4_INTFLAGS
+ #define INT_MASK TCB_CAPT_bm
+
+ #define TICK_init() { \
+ TCB4.CCMP = configCPU_CLOCK_HZ / configTICK_RATE_HZ; \
+ TCB4.INTCTRL = TCB_CAPT_bm; \
+ TCB4.CTRLA = TCB_ENABLE_bm; \
+ }
+
+ #define TICK_stop() { \
+ TCB4.INTCTRL &= ~TCB_CAPT_bm; \
+ TCB4.CTRLA &= ~TCB_ENABLE_bm; \
+ }
+
+#elif ( configUSE_TIMER_INSTANCE == 5 )
+
+ /* Hertz to period for RTC setup */
+ #define RTC_PERIOD_HZ(x) (32768 * ((1.0 / x)))
+
+ #define TICK_INT_vect RTC_CNT_vect
+ #define INT_FLAGS RTC_INTFLAGS
+ #define INT_MASK RTC_OVF_bm
+
+ #define TICK_init() { \
+ while (RTC.STATUS > 0); \
+ RTC.CTRLA = RTC_PRESCALER_DIV1_gc | 1 << RTC_RTCEN_bp; \
+ RTC.PER = RTC_PERIOD_HZ(configTICK_RATE_HZ); \
+ RTC.INTCTRL |= 1 << RTC_OVF_bp; \
+ }
+
+ #define TICK_stop() { \
+ RTC.CTRLA &= ~(1 << RTC_RTCEN_bp); \
+ RTC.INTCTRL &= ~(1 << RTC_OVF_bp); \
+ }
+
+#else
+ #undef TICK_INT_vect
+ #undef INT_FLAGS
+ #undef INT_MASK
+ #undef TICK_init()
+ #error Invalid timer setting.
+#endif
+
+/*-----------------------------------------------------------*/
+
+#endif /* PORTHARDWARE_H */
diff --git a/portable/GCC/AVR_AVRDx/portmacro.h b/portable/GCC/AVR_AVRDx/portmacro.h
new file mode 100644
index 0000000..83d41d3
--- /dev/null
+++ b/portable/GCC/AVR_AVRDx/portmacro.h
@@ -0,0 +1,107 @@
+/*
+ * FreeRTOS Kernel V10.3.1
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://www.FreeRTOS.org
+ * http://aws.amazon.com/freertos
+ *
+ * 1 tab == 4 spaces!
+*/
+
+#ifndef PORTMACRO_H
+#define PORTMACRO_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*-----------------------------------------------------------
+ * Port specific definitions.
+ *
+ * The settings in this file configure FreeRTOS correctly for the
+ * given hardware and compiler.
+ *
+ * These settings should not be altered.
+ *-----------------------------------------------------------
+ */
+
+/* Type definitions. */
+#define portCHAR char
+#define portFLOAT float
+#define portDOUBLE double
+#define portLONG long
+#define portSHORT int
+#define portSTACK_TYPE uint8_t
+#define portBASE_TYPE char
+
+#define portPOINTER_SIZE_TYPE uint16_t
+
+typedef portSTACK_TYPE StackType_t;
+typedef signed char BaseType_t;
+typedef unsigned char UBaseType_t;
+
+#if (configUSE_16_BIT_TICKS == 1)
+typedef uint16_t TickType_t;
+#define portMAX_DELAY (TickType_t)0xffff
+#else
+typedef uint32_t TickType_t;
+#define portMAX_DELAY (TickType_t)0xffffffffUL
+#endif
+
+/*-----------------------------------------------------------*/
+
+/* Critical section management. */
+#define portENTER_CRITICAL() \
+ asm volatile("in __tmp_reg__, __SREG__"); \
+ asm volatile("cli"); \
+ asm volatile("push __tmp_reg__")
+
+#define portEXIT_CRITICAL() \
+ asm volatile("pop __tmp_reg__"); \
+ asm volatile("out __SREG__, __tmp_reg__")
+
+#define portDISABLE_INTERRUPTS() asm volatile("cli" ::);
+#define portENABLE_INTERRUPTS() asm volatile("sei" ::);
+/*-----------------------------------------------------------*/
+
+/* Architecture specifics. */
+#define portSTACK_GROWTH (-1)
+#define portTICK_PERIOD_MS ((TickType_t)1000 / configTICK_RATE_HZ)
+#define portBYTE_ALIGNMENT 1
+#define portNOP() asm volatile("nop");
+/*-----------------------------------------------------------*/
+
+/* Kernel utilities. */
+extern void vPortYield(void) __attribute__((naked));
+#define portYIELD() vPortYield()
+
+extern void vPortYieldFromISR(void) __attribute__((naked));
+#define portYIELD_FROM_ISR() vPortYieldFromISR()
+/*-----------------------------------------------------------*/
+
+/* Task function macros as described on the FreeRTOS.org WEB site. */
+#define portTASK_FUNCTION_PROTO(vFunction, pvParameters) void vFunction(void *pvParameters)
+#define portTASK_FUNCTION(vFunction, pvParameters) void vFunction(void *pvParameters)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PORTMACRO_H */
diff --git a/portable/GCC/AVR_Mega0/port.c b/portable/GCC/AVR_Mega0/port.c
new file mode 100644
index 0000000..39cdd84
--- /dev/null
+++ b/portable/GCC/AVR_Mega0/port.c
@@ -0,0 +1,338 @@
+/*
+ * FreeRTOS Kernel V10.0.0
+ * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software. If you wish to use our Amazon
+ * FreeRTOS name, please do so in a fair use way that does not cause confusion.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://www.FreeRTOS.org
+ * http://aws.amazon.com/freertos
+ *
+ * 1 tab == 4 spaces!
+ */
+
+#include <stdlib.h>
+
+#include <avr/interrupt.h>
+
+#include "porthardware.h"
+
+#include "FreeRTOS.h"
+#include "task.h"
+
+/*-----------------------------------------------------------
+ * Implementation of functions defined in portable.h for the AVR port.
+ *----------------------------------------------------------*/
+
+/* Start tasks with interrupts enables. */
+#define portFLAGS_INT_ENABLED ((StackType_t) 0x80)
+
+/*-----------------------------------------------------------*/
+
+/* We require the address of the pxCurrentTCB variable, but don't want to know
+any details of its type. */
+typedef void RTOS_TCB_t;
+extern volatile RTOS_TCB_t *volatile pxCurrentTCB;
+
+/*-----------------------------------------------------------*/
+
+/*
+ * Macro to save all the general purpose registers, the save the stack pointer
+ * into the TCB.
+ *
+ * The first thing we do is save the flags then disable interrupts. This is to
+ * guard our stack against having a context switch interrupt after we have already
+ * pushed the registers onto the stack - causing the 32 registers to be on the
+ * stack twice.
+ *
+ * r1 is set to zero as the compiler expects it to be thus, however some
+ * of the math routines make use of R1.
+ *
+ * The interrupts will have been disabled during the call to portSAVE_CONTEXT()
+ * so we need not worry about reading/writing to the stack pointer.
+ */
+
+#define portSAVE_CONTEXT() \
+ asm volatile("push r0 \n\t" \
+ "in r0, __SREG__ \n\t" \
+ "cli \n\t" \
+ "push r0 \n\t" \
+ "push r1 \n\t" \
+ "clr r1 \n\t" \
+ "push r2 \n\t" \
+ "push r3 \n\t" \
+ "push r4 \n\t" \
+ "push r5 \n\t" \
+ "push r6 \n\t" \
+ "push r7 \n\t" \
+ "push r8 \n\t" \
+ "push r9 \n\t" \
+ "push r10 \n\t" \
+ "push r11 \n\t" \
+ "push r12 \n\t" \
+ "push r13 \n\t" \
+ "push r14 \n\t" \
+ "push r15 \n\t" \
+ "push r16 \n\t" \
+ "push r17 \n\t" \
+ "push r18 \n\t" \
+ "push r19 \n\t" \
+ "push r20 \n\t" \
+ "push r21 \n\t" \
+ "push r22 \n\t" \
+ "push r23 \n\t" \
+ "push r24 \n\t" \
+ "push r25 \n\t" \
+ "push r26 \n\t" \
+ "push r27 \n\t" \
+ "push r28 \n\t" \
+ "push r29 \n\t" \
+ "push r30 \n\t" \
+ "push r31 \n\t" \
+ "lds r26, pxCurrentTCB \n\t" \
+ "lds r27, pxCurrentTCB + 1 \n\t" \
+ "in r0, __SP_L__ \n\t" \
+ "st x+, r0 \n\t" \
+ "in r0, __SP_H__ \n\t" \
+ "st x+, r0 \n\t");
+
+/*
+ * Opposite to portSAVE_CONTEXT(). Interrupts will have been disabled during
+ * the context save so we can write to the stack pointer.
+ */
+
+#define portRESTORE_CONTEXT() \
+ asm volatile("lds r26, pxCurrentTCB \n\t" \
+ "lds r27, pxCurrentTCB + 1 \n\t" \
+ "ld r28, x+ \n\t" \
+ "out __SP_L__, r28 \n\t" \
+ "ld r29, x+ \n\t" \
+ "out __SP_H__, r29 \n\t" \
+ "pop r31 \n\t" \
+ "pop r30 \n\t" \
+ "pop r29 \n\t" \
+ "pop r28 \n\t" \
+ "pop r27 \n\t" \
+ "pop r26 \n\t" \
+ "pop r25 \n\t" \
+ "pop r24 \n\t" \
+ "pop r23 \n\t" \
+ "pop r22 \n\t" \
+ "pop r21 \n\t" \
+ "pop r20 \n\t" \
+ "pop r19 \n\t" \
+ "pop r18 \n\t" \
+ "pop r17 \n\t" \
+ "pop r16 \n\t" \
+ "pop r15 \n\t" \
+ "pop r14 \n\t" \
+ "pop r13 \n\t" \
+ "pop r12 \n\t" \
+ "pop r11 \n\t" \
+ "pop r10 \n\t" \
+ "pop r9 \n\t" \
+ "pop r8 \n\t" \
+ "pop r7 \n\t" \
+ "pop r6 \n\t" \
+ "pop r5 \n\t" \
+ "pop r4 \n\t" \
+ "pop r3 \n\t" \
+ "pop r2 \n\t" \
+ "pop r1 \n\t" \
+ "pop r0 \n\t" \
+ "out __SREG__, r0 \n\t" \
+ "pop r0 \n\t");
+
+/*-----------------------------------------------------------*/
+
+/*
+ * Perform hardware setup to enable ticks from timer.
+ */
+static void prvSetupTimerInterrupt(void);
+/*-----------------------------------------------------------*/
+
+/*
+ * See header file for description.
+ */
+StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters)
+{
+ uint16_t usAddress;
+
+ /*lint -e950 -e611 -e923 Lint doesn't like this much - but nothing I can do about it. */
+
+ /* Place a few bytes of known values on the bottom of the stack.
+ This is just useful for debugging. Uncomment if needed. */
+ // *pxTopOfStack = 0x11;
+ // pxTopOfStack--;
+ // *pxTopOfStack = 0x22;
+ // pxTopOfStack--;
+ // *pxTopOfStack = 0x33;
+ // pxTopOfStack--;
+
+ /* The start of the task code will be popped off the stack last, so place
+ it on first. */
+ usAddress = (uint16_t)pxCode;
+ *pxTopOfStack = (StackType_t)(usAddress & (uint16_t)0x00ff);
+ pxTopOfStack--;
+
+ usAddress >>= 8;
+ *pxTopOfStack = (StackType_t)(usAddress & (uint16_t)0x00ff);
+ pxTopOfStack--;
+
+ /* Next simulate the stack as if after a call to portSAVE_CONTEXT().
+ portSAVE_CONTEXT places the flags on the stack immediately after r0
+ to ensure the interrupts get disabled as soon as possible, and so ensuring
+ the stack use is minimal should a context switch interrupt occur. */
+ *pxTopOfStack = (StackType_t)0x00; /* R0 */
+ pxTopOfStack--;
+ *pxTopOfStack = portFLAGS_INT_ENABLED;
+ pxTopOfStack--;
+
+ /* Now the remaining registers. The compiler expects R1 to be 0. */
+ *pxTopOfStack = (StackType_t)0x00; /* R1 */
+
+ /* Leave R2 - R23 untouched */
+ pxTopOfStack -= 23;
+
+ /* Place the parameter on the stack in the expected location. */
+ usAddress = (uint16_t)pvParameters;
+ *pxTopOfStack = (StackType_t)(usAddress & (uint16_t)0x00ff);
+ pxTopOfStack--;
+
+ usAddress >>= 8;
+ *pxTopOfStack = (StackType_t)(usAddress & (uint16_t)0x00ff);
+
+ /* Leave register R26 - R31 untouched */
+ pxTopOfStack -= 7;
+
+ /*lint +e950 +e611 +e923 */
+
+ return pxTopOfStack;
+}
+/*-----------------------------------------------------------*/
+
+BaseType_t xPortStartScheduler(void)
+{
+ /* Setup the hardware to generate the tick. */
+ prvSetupTimerInterrupt();
+
+ /* Restore the context of the first task that is going to run. */
+ portRESTORE_CONTEXT();
+
+ /* Simulate a function call end as generated by the compiler. We will now
+ jump to the start of the task the context of which we have just restored. */
+ asm volatile("ret");
+
+ /* Should not get here. */
+ return pdTRUE;
+}
+/*-----------------------------------------------------------*/
+
+void vPortEndScheduler(void)
+{
+ /* vPortEndScheduler is not implemented in this port. */
+}
+/*-----------------------------------------------------------*/
+
+/*
+ * Manual context switch. The first thing we do is save the registers so we
+ * can use a naked attribute.
+ */
+void vPortYield(void) __attribute__((naked));
+void vPortYield(void)
+{
+ portSAVE_CONTEXT();
+ vTaskSwitchContext();
+ portRESTORE_CONTEXT();
+ asm volatile("ret");
+}
+/*-----------------------------------------------------------*/
+
+/*
+ * 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__((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
+ * difference from vPortYield() is the tick count is incremented as the
+ * call comes from the tick ISR.
+ */
+void vPortYieldFromTick(void) __attribute__((naked));
+void vPortYieldFromTick(void)
+{
+ portSAVE_CONTEXT();
+ if (xTaskIncrementTick() != pdFALSE) {
+ vTaskSwitchContext();
+ }
+
+ portRESTORE_CONTEXT();
+
+ asm volatile("reti");
+}
+/*-----------------------------------------------------------*/
+
+/*
+ * Setup timer to generate a tick interrupt.
+ */
+static void prvSetupTimerInterrupt(void)
+{
+ TICK_init();
+}
+/*-----------------------------------------------------------*/
+
+#if configUSE_PREEMPTION == 1
+
+/*
+ * Tick ISR for preemptive scheduler. We can use a naked attribute as
+ * the context is saved at the start of vPortYieldFromTick(). The tick
+ * count is incremented after the context is saved.
+ */
+ISR(TICK_INT_vect, ISR_NAKED)
+{
+ /* Clear tick interrupt flag. */
+ CLR_INT(INT_FLAGS, INT_MASK);
+
+ vPortYieldFromTick();
+
+ asm volatile("reti");
+}
+#else
+
+/*
+ * Tick ISR for the cooperative scheduler. All this does is increment the
+ * tick count. We don't need to switch context, this can only be done by
+ * manual calls to taskYIELD();
+ */
+ISR(TICK_INT_vect)
+{
+ /* Clear tick interrupt flag. */
+ INT_FLAGS = INT_MASK;
+ xTaskIncrementTick();
+}
+#endif
diff --git a/portable/GCC/AVR_Mega0/porthardware.h b/portable/GCC/AVR_Mega0/porthardware.h
new file mode 100644
index 0000000..b0d9002
--- /dev/null
+++ b/portable/GCC/AVR_Mega0/porthardware.h
@@ -0,0 +1,113 @@
+#ifndef PORTHARDWARE_H
+#define PORTHARDWARE_H
+
+#include "FreeRTOSConfig.h"
+
+/*-----------------------------------------------------------*/
+
+#define CLR_INT(FLAG_REG, FLAG_MASK) \
+ asm volatile( "push r16\n\t" \
+ "ldi r16, %1\n\t" \
+ "sts %0, r16\n\t" \
+ "pop r16\n\t" \
+ : \
+ : "i"(_SFR_MEM_ADDR(FLAG_REG)),"i"((uint8_t)(FLAG_MASK)) \
+ );
+
+#if ( configUSE_TIMER_INSTANCE == 0 )
+
+ #define TICK_INT_vect TCB0_INT_vect
+ #define INT_FLAGS TCB0_INTFLAGS
+ #define INT_MASK TCB_CAPT_bm
+
+ #define TICK_init() { \
+ TCB0.CCMP = configCPU_CLOCK_HZ / configTICK_RATE_HZ; \
+ TCB0.INTCTRL = TCB_CAPT_bm; \
+ TCB0.CTRLA = TCB_ENABLE_bm; \
+ }
+
+ #define TICK_stop() { \
+ TCB0.INTCTRL &= ~TCB_CAPT_bm;\
+ TCB0.CTRLA &= ~TCB_ENABLE_bm; \
+ }
+
+#elif ( configUSE_TIMER_INSTANCE == 1 )
+
+ #define TICK_INT_vect TCB1_INT_vect
+ #define INT_FLAGS TCB1_INTFLAGS
+ #define INT_MASK TCB_CAPT_bm
+
+ #define TICK_init() { \
+ TCB1.CCMP = configCPU_CLOCK_HZ / configTICK_RATE_HZ; \
+ TCB1.INTCTRL = TCB_CAPT_bm; \
+ TCB1.CTRLA = TCB_ENABLE_bm; \
+ }
+
+ #define TICK_stop() { \
+ TCB1.INTCTRL &= ~TCB_CAPT_bm; \
+ TCB1.CTRLA &= ~TCB_ENABLE_bm; \
+ }
+
+#elif ( configUSE_TIMER_INSTANCE == 2 )
+
+ #define TICK_INT_vect TCB2_INT_vect
+ #define INT_FLAGS TCB2_INTFLAGS
+ #define INT_MASK TCB_CAPT_bm
+
+ #define TICK_init() { \
+ TCB2.CCMP = configCPU_CLOCK_HZ / configTICK_RATE_HZ; \
+ TCB2.INTCTRL = TCB_CAPT_bm; \
+ TCB2.CTRLA = TCB_ENABLE_bm; \
+ }
+
+ #define TICK_stop() { \
+ TCB2.INTCTRL &= ~TCB_CAPT_bm; \
+ TCB2.CTRLA &= ~TCB_ENABLE_bm; \
+ }
+
+#elif ( configUSE_TIMER_INSTANCE == 3 )
+
+ #define TICK_INT_vect TCB3_INT_vect
+ #define INT_FLAGS TCB3_INTFLAGS
+ #define INT_MASK TCB_CAPT_bm
+
+ #define TICK_init() { \
+ TCB3.CCMP = configCPU_CLOCK_HZ / configTICK_RATE_HZ; \
+ TCB3.INTCTRL = TCB_CAPT_bm; \
+ TCB3.CTRLA = TCB_ENABLE_bm; \
+ }
+
+ #define TICK_stop() { \
+ TCB3.INTCTRL &= ~TCB_CAPT_bm; \
+ TCB3.CTRLA &= ~TCB_ENABLE_bm; \
+ }
+
+#elif ( configUSE_TIMER_INSTANCE == 4 )
+
+ #define TICK_INT_vect RTC_CNT_vect
+ #define INT_FLAGS RTC_INTFLAGS
+ #define INT_MASK RTC_OVF_bm
+
+ #define RTC_PERIOD_HZ(x) (32768 * ( (1.0 / x) ) )
+ #define TICK_init() { \
+ while (RTC.STATUS > 0); \
+ RTC.CTRLA = RTC_PRESCALER_DIV1_gc | 1 << RTC_RTCEN_bp; \
+ RTC.PER = RTC_PERIOD_HZ(configTICK_RATE_HZ); \
+ RTC.INTCTRL |= 1 << RTC_OVF_bp; \
+ }
+
+ #define TICK_stop() { \
+ RTC.CTRLA &= ~(1 << RTC_RTCEN_bp); \
+ RTC.INTCTRL &= ~(1 << RTC_OVF_bp); \
+ }
+
+#else
+#undef TICK_INT_vect
+#undef INT_FLAGS
+#undef INT_MASK
+#error Invalid timer setting
+#endif
+
+/*-----------------------------------------------------------*/
+
+#endif /* PORTHARDWARE_H */
diff --git a/portable/GCC/AVR_Mega0/portmacro.h b/portable/GCC/AVR_Mega0/portmacro.h
new file mode 100644
index 0000000..040f498
--- /dev/null
+++ b/portable/GCC/AVR_Mega0/portmacro.h
@@ -0,0 +1,109 @@
+/*
+ * FreeRTOS Kernel V10.3.1
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://www.FreeRTOS.org
+ * http://aws.amazon.com/freertos
+ *
+ * 1 tab == 4 spaces!
+*/
+
+#ifndef PORTMACRO_H
+#define PORTMACRO_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*-----------------------------------------------------------
+ * Port specific definitions.
+ *
+ * The settings in this file configure FreeRTOS correctly for the
+ * given hardware and compiler.
+ *
+ * These settings should not be altered.
+ *-----------------------------------------------------------
+ */
+
+/* Type definitions. */
+#define portCHAR char
+#define portFLOAT float
+#define portDOUBLE double
+#define portLONG long
+#define portSHORT int
+#define portSTACK_TYPE uint8_t
+#define portBASE_TYPE char
+
+#define portPOINTER_SIZE_TYPE uint16_t
+
+typedef portSTACK_TYPE StackType_t;
+typedef signed char BaseType_t;
+typedef unsigned char UBaseType_t;
+
+#if (configUSE_16_BIT_TICKS == 1)
+typedef uint16_t TickType_t;
+#define portMAX_DELAY (TickType_t)0xffff
+#else
+typedef uint32_t TickType_t;
+#define portMAX_DELAY (TickType_t)0xffffffffUL
+#endif
+/*-----------------------------------------------------------*/
+
+/* Critical section management. */
+#define portENTER_CRITICAL() \
+ asm volatile("in __tmp_reg__, __SREG__"); \
+ asm volatile("cli"); \
+ asm volatile("push __tmp_reg__")
+
+#define portEXIT_CRITICAL() \
+ asm volatile("pop __tmp_reg__"); \
+ asm volatile("out __SREG__, __tmp_reg__")
+
+#define portDISABLE_INTERRUPTS() asm volatile("cli" ::);
+#define portENABLE_INTERRUPTS() asm volatile("sei" ::);
+/*-----------------------------------------------------------*/
+
+/* Architecture specifics. */
+#define portSTACK_GROWTH (-1)
+#define portTICK_PERIOD_MS ((TickType_t)1000 / configTICK_RATE_HZ)
+#define portBYTE_ALIGNMENT 1
+#define portNOP() asm volatile("nop");
+
+/*-----------------------------------------------------------*/
+
+/* Kernel utilities. */
+extern void vPortYield(void) __attribute__((naked));
+#define portYIELD() vPortYield()
+
+extern void vPortYieldFromISR(void) __attribute__((naked));
+#define portYIELD_FROM_ISR() vPortYieldFromISR()
+
+/*-----------------------------------------------------------*/
+
+/* Task function macros as described on the FreeRTOS.org WEB site. */
+#define portTASK_FUNCTION_PROTO(vFunction, pvParameters) void vFunction(void *pvParameters)
+#define portTASK_FUNCTION(vFunction, pvParameters) void vFunction(void *pvParameters)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PORTMACRO_H */
+
