aversive_10-03-12/modules/debug/diagnostic/stack_space.c

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/*  
 *  Copyright Droids Corporation, Microb Technology, Eirbot (2005)
 * 
 *  This program 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  Revision : $Id: stack_space.c,v 1.9 2008-05-14 13:27:12 zer0 Exp $
 *
 */

#include <avr/io.h>
#include <aversive.h>


#include <diagnostic.h>


// call this function at the beginning of program
void fill_mem_with_mark(void) __attribute__ ((naked)) \
__attribute__ ((section (".init1")));


void fill_mem_with_mark(void)
{
        register int i   asm("r16");
        register int end asm("r18");


        // where is the beginning of the RAM memory ?
#ifdef DIAG_FILL_ENTIRE_RAM // fill entire RAM
        asm(  "ldi r16,lo8(__data_start)" );
        asm(  "ldi r17,hi8(__data_start)" );
#else                       // fill only stack and heap spaces
        asm(  "ldi r16,lo8(__heap_start)" );
        asm(  "ldi r17,hi8(__heap_start)" );
#endif

        // end of RAM
        asm(  "ldi r18,lo8(__stack)" );
        asm(  "ldi r19,hi8(__stack)" );
  
        // fill ram with the spacified pattern
        for(; i< end ; i++)
                * ( (volatile unsigned char* )(i) ) = MARK;

}


uint16_t min_stack_space_available(void)
{
        register int i   asm("r16");
        register int end asm("r18");
        uint16_t count , max;

        // where is the beginning of the stack space ?
        asm(  "ldi r16,lo8(__heap_start)" );
        asm(  "ldi r17,hi8(__heap_start)" );
        // end of RAM
        asm(  "ldi r18,lo8(__stack)" );
        asm(  "ldi r19,hi8(__stack)" );
  
        /* the algorithm finds the size of the biggest zone filled
         * with the mark, which is normally the stack space left */
        count = 0;
        max  = 0;
        for(; i<end; i++) {
                // = mark?
                if (MARK == * ( (volatile unsigned char* )(i) )) {
                        // count
                        count ++;
                        if (count > max)
                                max = count;
                }
                else
                        count = 0; // reset counter
        }
        
        return max;
}

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