Add method to automatically retrieve sketch start

The exported variable is used by banzai() to avoid erasing any bootloader part

Author: facchinm

VARIANT_COMPLIANCE_CHANGELOG

@@ -1,3 +1,7 @@
+SAMD CORE 1.6.10
+
+* the linker script is use should define __text_start__ symbol at the beginning of .text section
+
 SAMD CORE 1.6.6
 
 * digitalPinToInterrupt #define moved to Arduino.h, variant.h must no longer define it

cores/arduino/Reset.cpp

@@ -24,7 +24,15 @@ extern "C" {
 #endif
 
 #define NVM_MEMORY ((volatile uint16_t *)0x000000)
+
+#if (ARDUINO_SAMD_VARIANT_COMPLIANCE >= 10610)
+
+extern const uint32_t __text_start__;
+#define APP_START ((volatile uint32_t)(&__text_start__) + 4)
+
+#else
 #define APP_START 0x00002004
+#endif
 
 static inline bool nvmReady(void) {
         return NVMCTRL->INTFLAG.reg & NVMCTRL_INTFLAG_READY;

variants/arduino_zero/linker_scripts/gcc/flash_with_bootloader.ld

@@ -65,6 +65,8 @@ SECTIONS
 {
 	.text :
 	{
+		__text_start__ = .;
+
 		KEEP(*(.isr_vector))
 		*(.text*)
 

variants/arduino_zero/linker_scripts/gcc/flash_without_bootloader.ld

@@ -66,6 +66,8 @@ SECTIONS
 {
 	.text :
 	{
+		__text_start__ = .;
+
 		KEEP(*(.isr_vector))
 		*(.text*)
 

variants/arduino_zero/variant.h

@@ -19,8 +19,8 @@
 #ifndef _VARIANT_ARDUINO_ZERO_
 #define _VARIANT_ARDUINO_ZERO_
 
-// The definitions here needs a SAMD core >=1.6.6
-#define ARDUINO_SAMD_VARIANT_COMPLIANCE 10606
+// The definitions here needs a SAMD core >=1.6.10
+#define ARDUINO_SAMD_VARIANT_COMPLIANCE 10610
 
 /*----------------------------------------------------------------------------
  *        Definitions

variants/mkr1000/linker_scripts/gcc/flash_with_bootloader.ld

@@ -65,6 +65,8 @@ SECTIONS
 {
 	.text :
 	{
+		__text_start__ = .;
+
 		KEEP(*(.isr_vector))
 		*(.text*)
 

variants/mkr1000/linker_scripts/gcc/flash_without_bootloader.ld

@@ -66,6 +66,8 @@ SECTIONS
 {
 	.text :
 	{
+		__text_start__ = .;
+
 		KEEP(*(.isr_vector))
 		*(.text*)
 

variants/mkr1000/variant.h

@@ -18,8 +18,8 @@
 
 #pragma once
 
-// The definitions here needs a SAMD core >=1.6.6
-#define ARDUINO_SAMD_VARIANT_COMPLIANCE 10606
+// The definitions here needs a SAMD core >=1.6.10
+#define ARDUINO_SAMD_VARIANT_COMPLIANCE 10610
 
 #include <WVariant.h>
 

variants/mkrzero/linker_scripts/gcc/flash_with_bootloader.ld

@@ -65,6 +65,8 @@ SECTIONS
 {
 	.text :
 	{
+		__text_start__ = .;
+
 		KEEP(*(.isr_vector))
 		*(.text*)
 

variants/mkrzero/linker_scripts/gcc/flash_without_bootloader.ld

@@ -66,6 +66,8 @@ SECTIONS
 {
 	.text :
 	{
+		__text_start__ = .;
+
 		KEEP(*(.isr_vector))
 		*(.text*)