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RIOT/cpu/atmega_common/irq_arch.c 1.98 KB
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  /*
   * Copyright (C) 2014 Freie Universitรคt Berlin, Hinnerk van Bruinehsen
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @ingroup     cpu_atmega_common
   * @{
   *
   * @file
   * @brief       Implementation of the kernels irq interface
   *
   * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
   * @author      Hinnerk van Bruinehsen <h.v.bruinehsen@fu-berlin.de>
   *
   * @}
   */
  
  #include <stdint.h>
  #include <stdio.h>
  #include "arch/irq_arch.h"
  #include "cpu.h"
  
  /**
   * @brief Macro returns state of the global interrupt register
   */
  static uint8_t __get_interrupt_state(void);
  static void __set_interrupt_state(uint8_t state);
  
  volatile uint8_t __in_isr = 0;
  
  __attribute__((always_inline)) static inline uint8_t  __get_interrupt_state(void)
  {
      uint8_t sreg;
      __asm__ volatile("in r0, __SREG__; \n\t"
                   "mov %0, r0       \n\t"
                   : "=g"(sreg)
                   :
                   : "r0");
      return sreg & (1 << 7);
  }
  
  __attribute__((always_inline)) inline void __set_interrupt_state(uint8_t state)
  {
      __asm__ volatile("mov r15,%0;       \n\t"
                   "in r16, __SREG__; \n\t"
                   "cbr r16,7;        \n\t"
                   "or r15,r16;       \n\t"
                   "out __SREG__, r15 \n\t"
                   :
                   : "g"(state)
                   : "r15", "r16");
  }
  
  /**
   * @brief Disable all maskable interrupts
   */
  unsigned int irq_arch_disable(void)
  {
      uint8_t mask = __get_interrupt_state();
      cli();
      return (unsigned int) mask;
  }
  
  /**
   * @brief Enable all maskable interrupts
   */
  unsigned int irq_arch_enable(void)
  {
      sei();
      return __get_interrupt_state();
  }
  
  /**
   * @brief Restore the state of the IRQ flags
   */
  void irq_arch_restore(unsigned int state)
  {
      __set_interrupt_state(state);
  }
  
  /**
   * @brief See if the current context is inside an ISR
   */
  int irq_arch_in(void)
  {
      return __in_isr;
  }