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Small optimization to ProcessMultiplier() for x86 CPUs.

master
mikaelh 2013-07-23 09:34:39 +03:00
parent c868744456
commit b0544e41e8
1 changed files with 22 additions and 0 deletions
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22
src/prime.h
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@ -96,6 +96,10 @@ unsigned int EstimateWorkTransition(unsigned int nPrevWorkTransition, unsigned i
// prime chain type and length value
std::string GetPrimeChainName(unsigned int nChainType, unsigned int nChainLength);
#if defined(__i386__) || defined(_M_IX86) || defined(_X86_) || defined(__x86_64__) || defined(_M_X64)
#define USE_ROTATE
#endif
// Sieve of Eratosthenes for proof-of-work mining
class CSieveOfEratosthenes
{
@ -131,14 +135,32 @@ class CSieveOfEratosthenes
void ProcessMultiplier(unsigned long *vfComposites, const unsigned int nMinMultiplier, const unsigned int nMaxMultiplier, const unsigned int nPrime, unsigned int *vMultipliers)
{
#ifdef USE_ROTATE
const unsigned int nRotateBits = nPrime % nWordBits;
for (unsigned int i = 0; i < nHalfChainLength; i++)
{
unsigned int nVariableMultiplier = vMultipliers[i];
if (nVariableMultiplier == 0xFFFFFFFF) break;
unsigned long lBitMask = GetBitMask(nVariableMultiplier);
for (; nVariableMultiplier < nMaxMultiplier; nVariableMultiplier += nPrime)
{
vfComposites[GetWordNum(nVariableMultiplier)] |= lBitMask;
lBitMask = (lBitMask << nRotateBits) | (lBitMask >> (nWordBits - nRotateBits));
}
vMultipliers[i] = nVariableMultiplier;
}
#else
for (unsigned int i = 0; i < nHalfChainLength; i++)
{
unsigned int nVariableMultiplier = vMultipliers[i];
if (nVariableMultiplier == 0xFFFFFFFF) break;
for (; nVariableMultiplier < nMaxMultiplier; nVariableMultiplier += nPrime)
{
vfComposites[GetWordNum(nVariableMultiplier)] |= GetBitMask(nVariableMultiplier);
}
vMultipliers[i] = nVariableMultiplier;
}
#endif
}
public: