//  **********************************************************************************************
//
//  File Name : isr.c
//  Title     : interrupt enable/disable functions
//
//
//  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.
//
//  Note from Jim Lynch:
//  This module was developed by Bill Knight, RO Software and used with his permission.
//  Taken from the Yahoo LPC2000 User's Group - Files Section 'UT050418A.ZIP'
//  Specifically, the module armVIC.c with the include file references removed
//  **********************************************************************************************

#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;
}