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#if __HAVE_BUILTIN_MUL_OVERFLOW && !defined(__MSP430__)
// gcc should use the correct one here
#define mul_overflow __builtin_mul_overflow
#else
/**
* Since __builtin_mul_overflow doesn't seem to exist,
* use a (slower) software implementation instead.
* This is only implemented for size_t, so in case mallocr.c's INTERNAL_SIZE_T
* is non default, mallocr.c throws an #error.
*/
static int
mul_overflow_size_t(size_t a, size_t b, size_t *res)
{
// always fill the result (gcc doesn't define what happens here)
if (res)
*res = a * b;
// multiply with 0 can not overflow (and avoid div-by-zero):
if (a == 0 || b == 0)
return 0;
#ifdef __MSP430__
volatile uint32_t ia = (uint32_t)a;
volatile uint32_t ib = (uint32_t)b;
// check if overflow would happen:
if ((ia > SIZE_MAX / ib) || (ib > SIZE_MAX / ia)) {
return 1;
}
#else
// check if overflow would happen:
if ((a > SIZE_MAX / b) || (b > SIZE_MAX / a)) {
return 1;
}
#endif
return 0;
}
#define mul_overflow mul_overflow_size_t
#endif
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