The problem is that LONG_BITS is 31, ie std::numeric_limits<long>::digits
returns 31 and not 32 which is what the writer expected.
--
Nilay
From: koreylsew...@gmail.com [mailto:koreylsew...@gmail.com] On Behalf Of
Korey Sewell
Sent: Tuesday, April 05, 2011 7:14 AM
To: Beckmann, Brad
Subject: Re: [m5-dev] Running Ruby w/32 Cores
Hi again Brad, I looked this over again and although my 32-bit patch
"fixes" things, now that I look at it again, I'm not convinced that I
actually fixed the symptom of the bug but rather the cause of the bug.
Do you happen to know what are the problems with the 32-bit Set counts?
Sorry for prolonging the issue, but I thought I had put this to bed but
maybe not. Finally, it may not matter that this works on 32-bit machines
but it'd be nice if it did. (Let me know if I should move this convo to
the m5-dev list)
I end up checking the last bit in the count function manually (the code
as follows): int Set::count() const {
int counter = 0;
long mask;
for (int i = 0; i < m_nArrayLen; i++) {
mask = (long)0x01;
for (int j = 0; j < LONG_BITS; j++) {
// FIXME - significant performance loss when array
// population << LONG_BITS
if ((m_p_nArray[i] & mask) != 0) {
counter++;
}
mask = mask << 1;
}
#ifndef _LP64
long msb_mask = 0x80000000;
if ((m_p_nArray[i] & msb_mask) != 0) {
counter++;
}
#endif
}
return counter;
}
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