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added memcheck library

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git-svn-id: https://arducopter.googlecode.com/svn/trunk@3206 f9c3cf11-9bcb-44bc-f272-b75c42450872
This commit is contained in:
tridge60@gmail.com 2011-09-01 00:50:31 +00:00
parent bba6b90104
commit 5cac97ca8d
2 changed files with 68 additions and 0 deletions
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62
libraries/memcheck/memcheck.cpp Normal file
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/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
note that we use a 32 bit sentinal to reduce the chance
of false positives with uninitialised stack variables
*/
#include <AP_Common.h>
static const uint32_t *stack_low;
extern unsigned __brkval;
#define STACK_OFFSET 2
#define SENTINAL 0x28021967
/*
return the current stack pointer
*/
static __attribute__((noinline)) const uint32_t *current_stackptr(void)
{
return (const uint32_t *)__builtin_frame_address(0);
}
/*
this can be added in deeply nested code to ensure we catch
deep stack usage. It should be caught by the sentinal, but this
is an added protection
*/
void memcheck_update_stackptr(void)
{
if (current_stackptr() < stack_low) {
unsigned s = (unsigned)(current_stackptr() - STACK_OFFSET);
stack_low = (uint32_t *)(s & ~3);
}
}
/*
initialise memcheck, setting up the sentinals
*/
void memcheck_init(void)
{
uint32_t *p;
free(malloc(1)); // ensure heap is initialised
stack_low = current_stackptr();
memcheck_update_stackptr();
for (p=(uint32_t *)(stack_low-1); p>(uint32_t *)__brkval; p--) {
*p = SENTINAL;
}
}
/*
this returns the real amount of free memory by looking for
overwrites of the stack sentinal values
*/
unsigned memcheck_available_memory(void)
{
memcheck_update_stackptr();
while (*stack_low != SENTINAL && stack_low > (const uint32_t *)__brkval) {
stack_low--;
}
return (unsigned)(stack_low) - __brkval;
}

6
libraries/memcheck/memcheck.h Normal file
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/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
unsigned memcheck_available_memory(void);
void memcheck_init(void);
void memcheck_update_stackptr(void);