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/**
* Marlin 3D Printer Firmware
* Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
/**
* InterruptVectors_Due.cpp - This module relocates the Interrupt vector table to SRAM,
* allowing to register new interrupt handlers at runtime. Specially valuable and needed
* because Arduino runtime allocates some interrupt handlers that we NEED to override to
* properly support extended functionality, as for example, USB host or USB device (MSD, MTP)
* and custom serial port handlers, and we don't actually want to modify and/or recompile the
* Arduino runtime. We just want to run as much as possible on Stock Arduino
*
* Copyright (c) 2017 Eduardo José Tagle. All right reserved
*/
#ifdef ARDUINO_ARCH_SAM
#include "../../inc/MarlinConfig.h"
#include "HAL.h"
#include "InterruptVectors.h"
/* The relocated Exception/Interrupt Table - According to the ARM
reference manual, alignment to 128 bytes should suffice, but in
practice, we need alignment to 256 bytes to make this work in all
cases */
__attribute__ ((aligned(256)))
static DeviceVectors ram_tab = { nullptr };
/**
* This function checks if the exception/interrupt table is already in SRAM or not.
* If it is not, then it copies the ROM table to the SRAM and relocates the table
* by reprogramming the NVIC registers
*/
static pfnISR_Handler* get_relocated_table_addr() {
// Get the address of the interrupt/exception table
uint32_t isrtab = SCB->VTOR;
// If already relocated, we are done!
if (isrtab >= IRAM0_ADDR)
return (pfnISR_Handler*)isrtab;
// Get the address of the table stored in FLASH
const pfnISR_Handler* romtab = (const pfnISR_Handler*)isrtab;
// Copy it to SRAM
memcpy(&ram_tab, romtab, sizeof(ram_tab));
// Disable global interrupts
CRITICAL_SECTION_START();
// Set the vector table base address to the SRAM copy
SCB->VTOR = (uint32_t)(&ram_tab);
// Reenable interrupts
CRITICAL_SECTION_END();
// Return the address of the table
return (pfnISR_Handler*)(&ram_tab);
}
pfnISR_Handler install_isr(IRQn_Type irq, pfnISR_Handler newHandler) {
// Get the address of the relocated table
pfnISR_Handler *isrtab = get_relocated_table_addr();
// Disable global interrupts
CRITICAL_SECTION_START();
// Get the original handler
pfnISR_Handler oldHandler = isrtab[irq + 16];
// Install the new one
isrtab[irq + 16] = newHandler;
// Reenable interrupts
CRITICAL_SECTION_END();
// Return the original one
return oldHandler;
}
#endif
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