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Fix hang with GCC64 when converting number to string

This commit is contained in:
coffeepots 2018-04-16 17:21:00 +01:00
parent ef59a023a3
commit 64350c4389
1 changed files with 15 additions and 10 deletions
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25
src/headers/ttmathuint_noasm.h
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@ -576,18 +576,23 @@ namespace ttmath
template<uint value_size>
sint UInt<value_size>::FindLeadingBitInWord(uint x)
{
if( x == 0 )
return -1;
// see: https://graphics.stanford.edu/~seander/bithacks.html#IntegerLogDeBruijn
// find the log base 2 of 32-bit x
int r; // result goes here
uint bit = TTMATH_BITS_PER_UINT - 1;
while( (x & TTMATH_UINT_HIGHEST_BIT) == 0 )
{
x = x << 1;
--bit;
}
static const int MultiplyDeBruijnBitPosition[32] =
{
0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30,
8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31};
return bit;
x |= x >> 1; // first round down to one less than a power of 2
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
r = MultiplyDeBruijnBitPosition[(uint32_t)(x * 0x07C4ACDDU) >> 27];
return r;
}