LeafLabs Garden » Topic: getFreeMemory code on the maple.

LeafLabs Garden » Topic: getFreeMemory code on the maple. http://forums.leaflabs.com/topic.php?id=2369 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:08:28 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://forums.leaflabs.com/search.php feurig on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-20841 Wed, 07 Nov 2012 01:43:26 +0000 feurig 20841@http://forums.leaflabs.com/ Also I couldn't get anything meaningful out of _sbrk by itself my current solution assumes that newlib is pretty dumb about its actual allocation so it remains to me unsolved. So I am perplexed at best..... <code> unsigned long int getFreeMemory() // none of this works. { static long int *testMalloc; unsigned long int freeMemory; testMalloc = (long int *) malloc(10); if (testMalloc==0) return 0; // freeMemory = (unsigned long int)CONFIG_HEAP_END - (unsigned long int)(testMalloc); freeMemory = (unsigned long int)(&freeMemory) - (unsigned long int)(testMalloc); // freeMemory = (unsigned long int)CONFIG_HEAP_END - (unsigned long int) _sbrk(0); // freeMemory = (long unsigned int) (&freeMemory) - (unsigned long int) _sbrk(0); free(testMalloc); return freeMemory; } </code> feurig on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-20833 Tue, 06 Nov 2012 17:34:16 +0000 feurig 20833@http://forums.leaflabs.com/ This doesn't take into account the stack though. feurig on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-20830 Tue, 06 Nov 2012 15:56:36 +0000 feurig 20830@http://forums.leaflabs.com/ As I was revisiting sys calls for other things. I was able to resolve this in a similar way <pre><code>#ifndef CONFIG_HEAP_START extern char _lm_heap_start; #define CONFIG_HEAP_START ((caddr_t)&_lm_heap_start) #endif #ifndef CONFIG_HEAP_END extern char _lm_heap_end; #define CONFIG_HEAP_END ((caddr_t)&_lm_heap_end) #endif unsigned long int getFreeMemory() { static long int *testMalloc; unsigned long int freeMemory; testMalloc = (long int *) malloc(10); if (testMalloc==0) return 0; freeMemory = (unsigned long int)CONFIG_HEAP_END - (unsigned long int)(testMalloc); free(testMalloc); return freeMemory; }</code></pre> I am getting a similar number ~13K which makes sense given that there is 20k to work with. This also flys in the face of the documentation that claims that you can't malloc. chipaudette on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-20313 Tue, 16 Oct 2012 11:56:44 +0000 chipaudette 20313@http://forums.leaflabs.com/ Has there been any progress on this? I used the information above to get a value returned by _sbrk, but I'm not sure if it is meaningful. Here's what I did to get it to return something at all... <pre><code>#include "syscalls.c" extern caddr_t _sbrk(int incr); #ifndef CONFIG_HEAP_END extern char _lm_heap_end; #define CONFIG_HEAP_END ((caddr_t)&_lm_heap_end) #endif int getFreeMemory() { return CONFIG_HEAP_END - _sbrk(0); }</code></pre> I did not edit my common.inc. It is stock from the 0.0.12 distrubtion. For my current program, calling <code>SerialUSB.println(getFreeMemory());</code> returns a value of 14224. Is this really the number of bytes that I have free? Or, do I need to do the mod to the common.inc? Thanks, Chip mbolivar on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-12510 Fri, 17 Aug 2012 16:22:35 +0000 mbolivar 12510@http://forums.leaflabs.com/ I see. Bummer. I've never used FreeRTOS, so I can't really help here. Speaking of toolchains, have you tried the new gcc-arm-embedded support out? Should work in latest master. feurig on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-12473 Thu, 16 Aug 2012 20:13:34 +0000 feurig 12473@http://forums.leaflabs.com/ Actually the freertos that you are distributing uses heap_2 which does not use newlib, and i couldn't get heap_3 which would wrap newlib's implementation to work (which sucks because I am very fond of stdio and most of the ansi stuff). I will try to post some blog stuff about my experiences with "FreeRtos vs libmaple vs Newlib". As the toolchain moves forward it should get less painful one would hope. <a href="http://michaldemin.wordpress.com/2010/03/09/freertos-newlib-on-cortex-m3/" rel="nofollow">http://michaldemin.wordpress.com/2010/03/09/freertos-newlib-on-cortex-m3/</a> does a pretty good job of describing some of the issue. Although things that depend on how you compile newlib really don't generalize or integrate well. mbolivar on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-12451 Wed, 15 Aug 2012 14:51:36 +0000 mbolivar 12451@http://forums.leaflabs.com/ <blockquote> I was trying to debug some FreeRTOS code which allocates from the heap outside of this mechanism anyways. </blockquote> Curious -- what do you mean? If the FreeRTOS code uses malloc(), then it should be using newlib's implementation, which uses our _sbrk() to request more space. Our _sbrk() respects _lm_heap_end, so you should be OK, unless I've misunderstood. feurig on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-12434 Wed, 15 Aug 2012 01:36:07 +0000 feurig 12434@http://forums.leaflabs.com/ Mbolivar, Thanks. I will come back to this. I was trying to debug some FreeRTOS code which allocates from the heap outside of this mechanism anyways. mbolivar on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-12290 Fri, 10 Aug 2012 16:26:07 +0000 mbolivar 12290@http://forums.leaflabs.com/ libmaple's linker script will always define <code>_lm_heap_end</code>; however, on most boards, its value is the initial stack pointer (so the heap and stack overlap). Probably the right thing to do is put it somewhere below the stack, so there's a minimum guaranteed stack size. Then, as long as you don't use too much stack, you could use <code>_lm_heap_end</code> safely to build a getFreeMemory() type function. Would you care to prepare a patch? See support/ld/common.inc: <pre><code>/* * Heap: Linker scripts may choose a custom heap by overriding * _lm_heap_start and _lm_heap_end. Otherwise, the heap is in * internal SRAM, beginning after .bss, and growing towards * the stack. * * I'm shoving these here naively; there's probably a cleaner way * to go about this. [mbolivar] */ _lm_heap_start = DEFINED(_lm_heap_start) ? _lm_heap_start : _end; _lm_heap_end = DEFINED(_lm_heap_end) ? _lm_heap_end : __msp_init;</code></pre> feurig on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-12284 Fri, 10 Aug 2012 12:50:37 +0000 feurig 12284@http://forums.leaflabs.com/ The reason that doesnt compile is because its basically the same avr-gcc code as above. I am playing around with something along these lines. extern caddr_t _sbrk(int incr); #ifndef CONFIG_HEAP_END extern char _lm_heap_end; #define CONFIG_HEAP_END ((caddr_t)&_lm_heap_end) #endif int getFreeMemory() { return CONFIG_HEAP_END - _sbrk(0); } If anyone has any better ideas that would be swell. shark2600 on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-12280 Fri, 10 Aug 2012 08:53:33 +0000 shark2600 12280@http://forums.leaflabs.com/ There is a FreeRam function in dinau's SdFatMaple-vld lib. It is under condition #if 0, I couldn't get it compiled, one symbol is missing. Hope this can help you. <a href="https://bitbucket.org/dinau/sdfatmaple-vld/src/a386d1505010/SdFatUtil.h" rel="nofollow">https://bitbucket.org/dinau/sdfatmaple-vld/src/a386d1505010/SdFatUtil.h</a> /** Return the number of bytes currently free in RAM. */ #if 0 static int FreeRam(void) { extern int __bss_end; extern int* __brkval; int free_memory; if (reinterpret_cast<int>(__brkval) == 0) { // if no heap use from end of bss section free_memory = reinterpret_cast<int>(&free_memory) - reinterpret_cast<int>(&__bss_end); } else { // use from top of stack to heap free_memory = reinterpret_cast<int>(&free_memory) - reinterpret_cast<int>(__brkval); } return free_memory; } #endif feurig on "getFreeMemory code on the maple." http://forums.leaflabs.com/topic.php?id=2369#post-12262 Thu, 09 Aug 2012 14:41:13 +0000 feurig 12262@http://forums.leaflabs.com/ Dumb question. What is the best way to get the free memory available on the maple? In avr-gcc you would do this. extern int __bss_end; extern void *__brkval; int getFreeMemory() { int free_memory; if((int)__brkval == 0) free_memory = ((int)&free_memory) - ((int)&__bss_end); else free_memory = ((int)&free_memory) - ((int)__brkval); return free_memory; }