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drop own BitScanForward64 #1007

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Merged
opcm merged 2 commits into from
Mar 27, 2026
+1 −12
Merged

drop own BitScanForward64 #1007

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fe13646
drop own BitScanForward64
rdementi Mar 27, 2026
5bb8ba6
drop old compiler support (MSVC 2017)
opcm Mar 27, 2026
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1 change: 0 additions & 1 deletion appveyor.yml
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Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
version: 1.0.{build}
image:
- Visual Studio 2019
- Visual Studio 2017
configuration: Release
platform: x64
before_build:
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12 changes: 1 addition & 11 deletions src/cpucounters.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7425,19 +7425,9 @@ int32 PCM::mapNUMANodeToSocket(uint32 numa_node_id) const

if (mask != 0)
{
auto BitScanForward64 = [](unsigned long* Index, uint64_t Mask)
{
if (Mask == 0) return 0;

// Magic numbers for LSB (chess engine style)
static const uint64_t magic = 0x03f79d71b4cb0a89ULL;
uint64_t isolated = Mask & -Mask; // Rightmost set bit
*Index = (unsigned long)(((isolated * magic) >> 58));
};

// Find first set bit (first processor in this NUMA node within this group)
DWORD bitPosition = 0;
BitScanForward64(&bitPosition, mask);
_BitScanForward64(&bitPosition, mask);

// On Windows, we need to find the logical processor ID that corresponds to
// this bit position in this group. We iterate through topology to find a match.
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