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#ifndef __ALT_EXCEPTIONS_H__

#define __ALT_EXCEPTIONS_H__

/******************************************************************************

*                                                                             *

* License Agreement                                                           *

*                                                                             *

* Copyright (c) 2008 Altera Corporation, San Jose, California, USA.           *

* All rights reserved.                                                        *

*                                                                             *

* Permission is hereby granted, free of charge, to any person obtaining a     *

* copy of this software and associated documentation files (the "Software"),  *

* to deal in the Software without restriction, including without limitation   *

* the rights to use, copy, modify, merge, publish, distribute, sublicense,    *

* and/or sell copies of the Software, and to permit persons to whom the       *

* Software is furnished to do so, subject to the following conditions:        *

*                                                                             *

* The above copyright notice and this permission notice shall be included in  *

* all copies or substantial portions of the Software.                         *

*                                                                             *

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR  *

* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,    *

* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE *

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* DEALINGS IN THE SOFTWARE.                                                   *

*                                                                             *

* This agreement shall be governed in all respects by the laws of the State   *

* of California and by the laws of the United States of America.              *

*                                                                             *

******************************************************************************/

#include "alt_types.h"

#include "system.h"

#ifdef __cplusplus

extern "C"

{

#endif /* __cplusplus */

/*

 * This file defines instruction-generated exception handling and registry

 * API, exception type enumeration, and handler return value enumeration for

 * Nios II.

 */

/*

 * The following enumeration describes the value in the CPU EXCEPTION

 * register CAUSE bit field.

 */

enum alt_exception_cause_e {

  /*

   * This value is passed to an exception handler's cause argument if

   * "extra exceptions" information (EXECPTION) register is not

   * present in the processor hardware configuration.

   */

  NIOS2_EXCEPTION_CAUSE_NOT_PRESENT            = -1,

  /*

   * Real values

   */

  NIOS2_EXCEPTION_RESET                        = 0,

  NIOS2_EXCEPTION_CPU_ONLY_RESET_REQUEST       = 1,

  NIOS2_EXCEPTION_INTERRUPT                    = 2,

  NIOS2_EXCEPTION_TRAP_INST                    = 3,

  NIOS2_EXCEPTION_UNIMPLEMENTED_INST           = 4,

  NIOS2_EXCEPTION_ILLEGAL_INST                 = 5,

  NIOS2_EXCEPTION_MISALIGNED_DATA_ADDR         = 6,

  NIOS2_EXCEPTION_MISALIGNED_TARGET_PC         = 7,

  NIOS2_EXCEPTION_DIVISION_ERROR               = 8,

  NIOS2_EXCEPTION_SUPERVISOR_ONLY_INST_ADDR    = 9,

  NIOS2_EXCEPTION_SUPERVISOR_ONLY_INST         = 10,

  NIOS2_EXCEPTION_SUPERVISOR_ONLY_DATA_ADDR    = 11,

  NIOS2_EXCEPTION_TLB_MISS                     = 12,

  NIOS2_EXCEPTION_TLB_EXECUTE_PERM_VIOLATION   = 13,

  NIOS2_EXCEPTION_TLB_READ_PERM_VIOLATION      = 14,

  NIOS2_EXCEPTION_TLB_WRITE_PERM_VIOLATION     = 15,

  NIOS2_EXCEPTION_MPU_INST_REGION_VIOLATION    = 16,

  NIOS2_EXCEPTION_MPU_DATA_REGION_VIOLATION    = 17,

  NIOS2_EXCEPTION_ECC_TLB_ERR                  = 18,

  NIOS2_EXCEPTION_ECC_FETCH_ERR                = 19,

  NIOS2_EXCEPTION_ECC_REGISTER_FILE_ERR        = 20,

  NIOS2_EXCEPTION_ECC_DATA_ERR                 = 21,

  NIOS2_EXCEPTION_ECC_DATA_CACHE_WRITEBACK_ERR = 22

};

typedef enum alt_exception_cause_e alt_exception_cause;

/*

 * These define valid return values for a user-defined instruction-generated

 * exception handler. The handler should return one of these to indicate

 * whether to re-issue the instruction that triggered the exception, or to

 * skip it.

 */

enum alt_exception_result_e {

  NIOS2_EXCEPTION_RETURN_REISSUE_INST = 0,

  NIOS2_EXCEPTION_RETURN_SKIP_INST    = 1

};

typedef enum alt_exception_result_e alt_exception_result;

/*

 * alt_instruction_exception_register() can be used to register an exception

 * handler for instruction-generated exceptions that are not handled by the

 * built-in exception handler (i.e. for interrupts).

 *

 * The registry API is optionally enabled through the "Enable

 * Instruction-related Exception API" HAL BSP setting, which will

 * define the macro below.

 */

#ifdef ALT_INCLUDE_INSTRUCTION_RELATED_EXCEPTION_API

void alt_instruction_exception_register (

  alt_exception_result (*exception_handler)(

    alt_exception_cause cause,

    alt_u32 exception_pc,

    alt_u32 bad_addr) );

#endif /*ALT_INCLUDE_INSTRUCTION_RELATED_EXCEPTION_API */

/*

 * alt_exception_cause_generated_bad_addr() indicates whether a particular

 * exception cause value was from an exception-type that generated a valid

 * address in the BADADDR register. The contents of BADADDR is passed to

 * a user-registered exception handler in all cases, whether valid or not.

 * This routine should be called to validate the bad_addr argument to

 * your exception handler.

 *

 * Note that this routine will return false (0) for causes

 * NIOS2_EXCEPTION_TLB_MISS and NIOS2_EXCEPTION_ECC_TLB_ERR.

 * You must read the TLBMISC.D field to determine if BADADDR

 * is valid for these (valid if TLBMISC.D = 1).

 */

int alt_exception_cause_generated_bad_addr(alt_exception_cause cause);

/*

 * alt_ecc_fatal_exception_register() is called to register a handler to

 * service likely fatal ECC error exceptions. Likely the handler will

 * assume that correct execution of the running software is not possible

 * and re-initialize the processor (e.g. jump to reset address).

 *

 * Passing null (0x0) in the handler argument will disable a previously-

 * registered handler.

 *

 * Note that if no handler is registered, just normal exception processing

 * occurs on a likely fatal ECC exception and the exception processing

 * code might trigger an infinite exception loop.

 *

 * Note that the handler isn't a C function: it must be written in

 * assembly-code because it doesn't support C language calling conventions

 * and it can't return.

 *

 * The handler code must be carefully written to avoid triggering

 * another fatal ECC exception and creating an infinite exception loop.

 * The handler must avoid reading registers in case the fatal ECC

 * error is a register file ECC error.

 * If a data cache is present, the handler must avoid instructions that

 * access the data cache in case the fatal ECC error is a data cache

 * related ECC error. This includes cacheable load, cacheable store,

 * non-cacheable store (because it looks in the data cache to update the

 * data cache if it hits), and all data cache management instructions except

 * for INITD.

 */

void alt_ecc_fatal_exception_register(alt_u32 handler);

#ifdef __cplusplus

}

#endif /* __cplusplus */

#endif /* __ALT_EXCEPTIONS_H__ */