interrupt_utils.c

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/******************************************************************************
 *
 * $RCSfile: $
 * $Revision: $
 *
 * This module provides the interface routines for setting up and
 * controlling the various interrupt modes present on the ARM processor.
 * Copyright 2004, R O SoftWare
 * No guarantees, warrantees, or promises, implied or otherwise.
 * May be used for hobby or commercial purposes provided copyright
 * notice remains intact.
 *
 *****************************************************************************/
#include "interrupt_utils.h"

#define IRQ_MASK 0x00000080
#define FIQ_MASK 0x00000040
#define INT_MASK (IRQ_MASK | FIQ_MASK)

static inline unsigned __get_cpsr(void)
{
  unsigned long retval;
  asm volatile (" mrs  %0, cpsr" : "=r" (retval) : /* no inputs */  );
  return retval;
}

static inline void __set_cpsr(unsigned val)
{
  asm volatile (" msr  cpsr, %0" : /* no outputs */ : "r" (val)  );
}

unsigned disableIRQ(void)
{
  unsigned _cpsr;

  _cpsr = __get_cpsr();
  __set_cpsr(_cpsr | IRQ_MASK);
  return _cpsr;
}

unsigned restoreIRQ(unsigned oldCPSR)
{
  unsigned _cpsr;

  _cpsr = __get_cpsr();
  __set_cpsr((_cpsr & ~IRQ_MASK) | (oldCPSR & IRQ_MASK));
  return _cpsr;
}

unsigned enableIRQ(void)
{
  unsigned _cpsr;

  _cpsr = __get_cpsr();
  __set_cpsr(_cpsr & ~IRQ_MASK);
  return _cpsr;
}

unsigned disableFIQ(void)
{
  unsigned _cpsr;

  _cpsr = __get_cpsr();
  __set_cpsr(_cpsr | FIQ_MASK);
  return _cpsr;
}

unsigned restoreFIQ(unsigned oldCPSR)
{
  unsigned _cpsr;

  _cpsr = __get_cpsr();
  __set_cpsr((_cpsr & ~FIQ_MASK) | (oldCPSR & FIQ_MASK));
  return _cpsr;
}

unsigned enableFIQ(void)
{
  unsigned _cpsr;

  _cpsr = __get_cpsr();
  __set_cpsr(_cpsr & ~FIQ_MASK);
  return _cpsr;
}