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/*
bug-3003.c
The wrong location is used for a local variable; observable effects vary by backend.
For stm8, this results in overwriting other local variables.
For z80, it results in use of location below the stack.
*/
#include <testfwk.h>
#include <stdint.h>
#include <string.h>
#pragma disable_warning 88
void g(void)
{
}
static volatile uint8_t* f(const uint8_t id)
{
volatile uint8_t* result = 0; // Bug: For stm8, this variable is accessed at stack at sp+255, overwriting part of buffer.
switch (id)
{
case 0:
result = (volatile uint8_t *)0x5000;
break;
case 1:
result = (volatile uint8_t *)0x5005;
break;
case 2:
result = (volatile uint8_t *)0x500a;
break;
}
g(); // This call overwrites result by the return address for z80.
return result;
}
#if defined (__SDCC_pdk14) || defined (__SDCC_pdk15) || defined (__SDCC_mcs51) || defined (__SDCC_STACK_AUTO) // Lack of memory
#define BUFFERSIZE 20
#else
#define BUFFERSIZE 300
#endif
void testBug(void)
{
unsigned char buffer[BUFFERSIZE]; // Bug: Overwritten in f() on stm8.
memset(buffer, 0xa5, BUFFERSIZE);
ASSERT(f(0) == (volatile uint8_t *)0x5000);
ASSERT(f(1) == (volatile uint8_t *)0x5005);
ASSERT(f(2) == (volatile uint8_t *)0x500a);
for(size_t i = 0; i < BUFFERSIZE; i++)
ASSERT (buffer[i] == 0xa5);
}
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