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CommandStation-EX/freeMemory.cpp
2021-03-09 10:27:38 +00:00

61 lines
1.7 KiB
C++

/*
* © 2020, Harald Barth
* © 2021, Neil McKechnie
*
* This file is part of Asbelos DCC-EX
*
* This 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.
*
* It 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 CommandStation. If not, see <https://www.gnu.org/licenses/>.
*/
#include <Arduino.h>
#include "freeMemory.h"
// thanks go to https://github.com/mpflaga/Arduino-MemoryFree
#if defined(__arm__)
extern "C" char* sbrk(int);
#elif defined(__AVR__)
extern char *__brkval;
extern char *__malloc_heap_start;
#else
#error Unsupported board type
#endif
static volatile int minimum_free_memory = 32767;
int freeMemory() {
char top;
#if defined(__arm__)
return &top - reinterpret_cast<char*>(sbrk(0));
#elif defined(__AVR__)
return __brkval ? &top - __brkval : &top - __malloc_heap_start;
#else
#error bailed out alredy above
#endif
}
// Update low ram level. Allow for extra bytes to be specified
// by estimation or inspection, that may be used by other
// called subroutines.
int updateMinimumFreeMemory(unsigned char extraBytes) {
byte sreg_save = SREG;
noInterrupts();
int spare = freeMemory()-extraBytes;
if (spare < minimum_free_memory) minimum_free_memory = spare;
int returnValue = minimum_free_memory;
SREG = sreg_save;
return returnValue;
}