stack.c

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/*
 * Copyright (c) 2011, George Oikonomou - <oikonomou@users.sourceforge.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the Contiki operating system.
 */

/**
 * \file
 *         8051 stack debugging facilities
 *
 * \author
 *         George Oikonomou - <oikonomou@users.sourceforge.net>
 *         Philippe Retornaz (EPFL)
 */
#include "contiki.h"

#ifndef STACK_POISON
#define STACK_POISON 0xAA
#endif

CC_AT_DATA uint8_t sp;

void
stack_poison(void)
{
  __asm
  mov r1, _SP
poison_loop:
  inc r1
  mov @r1, #STACK_POISON
  cjne r1, #0xFF, poison_loop
  __endasm;
}

uint8_t
stack_get_max(void)
{
  __data uint8_t *sp = (__data uint8_t *)0xff;
  uint8_t free = 0;

  while(*sp-- == STACK_POISON) {
    free++;
  }

  return 0xff - free;
}