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Add new library MemoryFree
This is the MemoryFree libary from http://playground.arduino.cc/code/AvailableMemory, rewritten specifically for Arduino 101 and tinyTILE. It provides some functions for querying available stack & heap space.
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‎libraries/MemoryFree/README.md

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## MemoryFree library for Arduino/Genuino101 and tinyTILE
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This library is a re-write of http://playground.arduino.cc/Code/AvailableMemory
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specifically for Curie-based devices. This library defines the same header file
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`MemoryFree.h`, and provides the function `freeMemory()`. In addition, two extra
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functions are provided; `freeHeap()`, for heap space only, and `freeStack()`,
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for free stack space. `freeStack()` can also be used to detect a stack overflow.
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The rewrite is necessary for two reasons:
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* AVR-based boards use a different implementation of `malloc()` than Curie-based
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boards, and in order to determine the amount of free heap space, we depend
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on specific symbols defined by the `malloc()` implementation. The `malloc()`
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implementation used by Curie-based devices
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[can be seen here](https://github.com/foss-for-synopsys-dwc-arc-processors/glibc).
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* Curie-based boards have a different memory layout than AVR-based boards. See
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the [linker script](https://github.com/01org/corelibs-arduino101/blob/master/variants/arduino_101/linker_scripts/flash.ld)
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for Arduino/Genuino 101 for details of the memory layout
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for Curie-based devices.
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## Functions
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`int freeHeap (void)`
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Returns the number of bytes free in the heap, i.e. the number of bytes free
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to be allocated using `malloc()`.
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`int freeStack (void)`
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Returns the number of bytes free in the stack, i.e. the space between the
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current stack frame and the end of the stack area. This function will return
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a negative number in the event of a stack overflow, representing the size of
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the overflow; for example, a return value of -20 means that the current stack
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frame is 20 bytes past the end of the stack area.
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`int freeMemory (void)`
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Returns the number of bytes free in both the stack and the heap. If a stack
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overflow has occurred, only the number of bytes free in the heap is returned.

‎libraries/MemoryFree/examples/freeMemory/freeMemory.ino

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/*
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* Copyright (c) 2016 Intel Corporation. All rights reserved.
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* See the bottom of this file for the license terms.
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*/
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#include <MemoryFree.h>
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void setup () {
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Serial.begin(9600);
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while(!Serial);
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}
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void loop() {
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char *p;
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Serial.println("Free memory: " + String(freeMemory()));
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Serial.println("Allocating 24 bytes ...");
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p = (char *)malloc(24);
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Serial.println("Free memory: " + String(freeMemory()));
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Serial.println("Freeing 24 bytes ...");
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free(p);
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Serial.println("Free memory: " + String(freeMemory()));
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delay(2000);
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}
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/*
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* Copyright (c) 2017 Intel Corporation. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/

‎libraries/MemoryFree/keywords.txt

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#######################################
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# Syntax Coloring Map For MemoryFree
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#######################################
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#######################################
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# Methods and Functions (KEYWORD2)
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#######################################
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freeStack KEYWORD2
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freeHeap KEYWORD2
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freeMemory KEYWORD2

‎libraries/MemoryFree/library.properties

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name=MemoryFree
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version=1.0
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author=Erik Nyquist
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maintainer=Erik Nyquist <eknyquist@gmail.com>
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sentence=Determines the amount of available memory in the heap
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paragraph=Determines the amount of memory, in bytes, that is available for allocation using malloc()
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category=Uncategorized
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url=
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architectures=arc32
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‎libraries/MemoryFree/src/MemoryFree.cpp

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/*
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* MemoryFree.cpp: taken from http://playground.arduino.cc/Code/AvailableMemory,
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* re-written for the Arduino 101 which uses a different malloc implementation.
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*
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* Arduino 101 malloc source:
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* https://github.com/foss-for-synopsys-dwc-arc-processors/glibc
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*
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* mallinfo() struct details:
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* http://man7.org/linux/man-pages/man3/mallinfo.3.html
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*
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* Copyright (c) 2017 Intel Corporation. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include <malloc.h>
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#include "MemoryFree.h"
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extern char __start_heap;
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extern char __end_heap;
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extern char __stack_size;
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extern char __stack_start;
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int freeStack() {
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int stack_end;
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int mark;
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stack_end = ((int)&__stack_start) - ((int)&__stack_size);
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return ((int)&mark) - stack_end;
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}
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int freeHeap (void) {
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int hsize;
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struct mallinfo mi;
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mi = mallinfo();
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hsize = (int)&__end_heap - (int)&__start_heap;
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return (hsize - mi.arena) + mi.fordblks;
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}
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int freeMemory (void) {
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int heap = freeHeap();
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int stack = freeStack();
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return (stack < 0) ? heap : stack + heap;
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}

‎libraries/MemoryFree/src/MemoryFree.h

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/*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#ifndef MEMORYFREE_H
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#define MEMORYFREE_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* freeHeap: returns the size (in bytes) of unused space on the heap,
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* i.e. the number of bytes available for allocation by 'malloc()' */
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int freeHeap(void);
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/* freeStack: returns the size (in bytes) of remaining free space in the stack,
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* i.e. the difference between our current position in the stack, and the end
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* of usable stack space.
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*
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* NOTE: This function will return a negative number to indicate a stack
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* overflow, i.e. a return value of -20 means you have overrun the allocated
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* stack area by 20 bytes. */
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int freeStack(void);
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/* freeMemory: returns the combined free memory in both the stack and heap,
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* except in the case where a stack overflow has occurred (i.e. freeStack
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* returns a negative number). In this case, only the amount of free heap
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* space will be returned. */
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int freeMemory(void);
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#ifdef __cplusplus
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}
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#endif
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#endif

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