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/* $Id: memtest.hh,v 1.8 2008-06-24 10:03:41 sybreon Exp $

**

** MEMORY TEST FUNCTIONS

** Copyright (C) 2008 Shawn Tan 

**

** This file is part of AEMB.

**

** AEMB is free software: you can redistribute it and/or modify it

** under the terms of the GNU General Public License as published by

** the Free Software Foundation, either version 3 of the License, or

** (at your option) any later version.

**

** AEMB is distributed in the hope that it will be useful, but WITHOUT

** ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

** or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public

** License for more details.

**

** You should have received a copy of the GNU General Public License

** along with AEMB.  If not, see .

*/

#ifndef MEMTEST_HH

#define MEMTEST_HH

#ifdef __cplusplus

extern "C" {

#endif

  /**

     WALKING ONES TEST

     Checks individual bit lines in O(1). Based on code at

     http://www.embedded.com/2000/0007/0007feat1list1.htm

  */

  static inline int memTestDataBus(int base)

  {

    volatile int *ram = (int *) base;

    for (int i=1; i!=0; i<<=1)

      {

        *ram = i; // write test value

        if (*ram != i) // read back test

          return i;

      }

    return 0; // 0 if success

  }

  /**

     POWERS OF TWO TEST

     Checks the address lines. Based on code at

     http://www.embedded.com/2000/0007/0007feat1list2.htm

  */

  static inline int memTestAddrBus(int base, int len)

  {

    volatile int *ram = (int *) base;

    const int p = 0xAAAAAAAA;

    const int q = 0x55555555;

    int nlen = (len / sizeof(int)) - 1;

    //int nlen = (SRAM_SIZE / 4) - 1;

    // prefill memory

    for (int i=1; (i & nlen)!=0 ; i<<=1)

      {

        ram[i] = p;

      }

    // check 1 - stuck high

    ram[0] = q;

    for (int i=1; (i & nlen)!=0 ; i<<=1)

      {

        if (ram[i] != p)

          return i;

      }

    // check 2 - stuck low

    ram[0] = p;

    for (int j=1; (j & nlen)!=0 ; j<<=1)

      {

        ram[j] = q;

        for (int i=1; (i & nlen)!=0 ; i<<=1)

          {

            if ((ram[i] != p) && (i != j))

              return i;

          }

        ram[j] = p;

      }

    return 0;

  }

  /**

     INCREMENT TEST

     Checks the entire memory device. Based on code at

     http://www.embedded.com/2000/0007/0007feat1list3.htm

  */

  static inline int memTestFullDev(int base, int len)

  {

    volatile int *ram = (int *) base;

    int nlen = len / sizeof(int);

    //int nlen = (SRAM_SIZE / 4);

    // prefill the memory

    for (int p=1, i=0; i

      {

        ram[i] = p;

      }

    // pass 1 - check and invert

    for (int p=1, i=0; i

      {

        if (ram[i] != p)

          return p;

        ram[i] = ~p;

      }

    // pass 2 - check and zero

    for (int p=1, i=0; i

      {

        if (ram[i] != ~p)

          return p;

        ram[i] = 0;

      }

    return 0;

  }

#ifdef __cplusplus

}

#endif

#endif

/*

  $Log: not supported by cvs2svn $

  Revision 1.7  2008/06/24 00:20:13  sybreon

  changed parameters passed

  Revision 1.6  2008/06/23 23:40:28  sybreon

  *** empty log message ***

  Revision 1.5  2008/06/23 22:28:00  sybreon

  resized fulldev test

  Revision 1.4  2008/06/23 22:08:39  sybreon

  Renamed functions

  Revision 1.3  2008/06/23 22:05:14  sybreon

  *** empty log message ***

  Revision 1.2  2008/06/21 10:01:35  sybreon

  *** empty log message ***

  Revision 1.1  2008/06/20 17:51:23  sybreon

  initial import

 */