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"Software"), to deal in the Software without restriction, including
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******************************************************************************/

/******************************************************************************
  Xtensa-specific interrupt and exception functions for RTOS ports.
  Also see xtensa_intr_asm.S.
******************************************************************************/

#include <stdlib.h>

#include <xtensa/config/core.h>

#include "xtensa_api.h"


#if XCHAL_HAVE_EXCEPTIONS

/* Handler table is in xtensa_intr_asm.S */

extern xt_exc_handler _xt_exception_table[XCHAL_EXCCAUSE_NUM];


/*
  Default handler for unhandled exceptions.
*/
void xt_unhandled_exception(XtExcFrame *frame)
{
    exit(-1);
}


/*
  This function registers a handler for the specified exception.
  The function returns the address of the previous handler.
  On error, it returns 0.
*/
xt_exc_handler xt_set_exception_handler(int n, xt_exc_handler f)
{
    xt_exc_handler old;

    if( n < 0 || n >= XCHAL_EXCCAUSE_NUM )
        return 0;       /* invalid exception number */

    old = _xt_exception_table[n];

    if (f) {
        _xt_exception_table[n] = f;
    }
    else {
        _xt_exception_table[n] = &xt_unhandled_exception;
    }

    return ((old == &xt_unhandled_exception) ? 0 : old);
}

#endif

#if XCHAL_HAVE_INTERRUPTS

/* Handler table is in xtensa_intr_asm.S */

typedef struct xt_handler_table_entry {
    void * handler;
    void * arg;
} xt_handler_table_entry;

extern xt_handler_table_entry _xt_interrupt_table[XCHAL_NUM_INTERRUPTS];


/*
  Default handler for unhandled interrupts.
*/
void xt_unhandled_interrupt(void * arg)
{
    exit(-1);
}


/*
  This function registers a handler for the specified interrupt. The "arg"
  parameter specifies the argument to be passed to the handler when it is
  invoked. The function returns the address of the previous handler.
  On error, it returns 0.
*/
xt_handler xt_set_interrupt_handler(int n, xt_handler f, void * arg)
{
    xt_handler_table_entry * entry;
    xt_handler               old;

    if( n < 0 || n >= XCHAL_NUM_INTERRUPTS )
        return 0;       /* invalid interrupt number */
    if( Xthal_intlevel[n] > XCHAL_EXCM_LEVEL )
        return 0;       /* priority level too high to safely handle in C */

    entry = _xt_interrupt_table + n;
    old   = entry->handler;

    if (f) {
        entry->handler = f;
        entry->arg     = arg;
    }
    else {
        entry->handler = &xt_unhandled_interrupt;
        entry->arg     = (void*)n;
    }

    return ((old == &xt_unhandled_interrupt) ? 0 : old);
}


#endif /* XCHAL_HAVE_INTERRUPTS */
