54 lines
1,016 B
C
54 lines
1,016 B
C
#pragma once
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#include "collatypes.h"
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uint32 bitsCtz(uint32 v);
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uint32 bitsNextPow2(uint32 v);
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// == INLINE IMPLEMENTATION ==============================================================
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#if COLLA_MSVC
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#define BITS_WIN 1
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#define BITS_LIN 0
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#include <intrin.h>
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#elif COLLA_GCC || COLLA_CLANG || COLLA_EMC
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#define BITS_WIN 0
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#define BITS_LIN 1
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#elif COLLA_TCC
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#define BITS_WIN 0
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#define BITS_LIN 0
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#else
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#error "bits header not supported on this compiler"
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#endif
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#include "tracelog.h"
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inline uint32 bitsCtz(uint32 v) {
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#if BITS_LIN
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return v ? __builtin_ctz(v) : 0;
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#elif BITS_WIN
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uint32 trailing = 0;
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return _BitScanForward((unsigned long *)&trailing, v) ? trailing : 32;
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#else
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if (v == 0) return 0;
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for (uint32 i = 0; i < 32; ++i) {
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if (v & (1 << i)) return i;
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}
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return 32;
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#endif
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}
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inline uint32 bitsNextPow2(uint32 v) {
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v--;
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v |= v >> 1;
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v |= v >> 2;
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v |= v >> 4;
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v |= v >> 8;
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v |= v >> 16;
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v++;
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return v;
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}
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#undef BITS_WIN
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#undef BITS_LIN
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