51 lines
1.7 KiB
Diff
51 lines
1.7 KiB
Diff
--- ../ffsl.h.orig 2021-11-09 21:28:29.347410128 +0100
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+++ ./lib/ffsl.h 2021-11-09 21:28:50.760733519 +0100
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@@ -46,47 +46,3 @@
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#if !defined FUNC || !defined TYPE
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# error
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#endif
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-
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-int
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-FUNC (TYPE i)
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-{
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-#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) \
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- || (__clang_major__ >= 4)
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- return GCC_BUILTIN (i);
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-#elif defined _MSC_VER && defined MSVC_BUILTIN
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- /* _BitScanForward, _BitScanForward64
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- <https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanforward-bitscanforward64> */
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- unsigned long bit;
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- if (MSVC_BUILTIN (&bit, i))
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- return bit + 1;
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- else
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- return 0;
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-#else
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- unsigned TYPE j = i;
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- /* Split j into chunks, and look at one chunk after the other. */
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- enum { chunk_bits = CHAR_BIT * sizeof (unsigned int) };
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- /* The number of chunks is ceil (sizeof (TYPE) / sizeof (unsigned int))
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- = (sizeof (TYPE) - 1) / sizeof (unsigned int) + 1. */
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- enum { chunk_count = (sizeof (TYPE) - 1) / sizeof (unsigned int) + 1 };
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-
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- if (chunk_count > 1)
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- {
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- size_t k;
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-
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- /* It is tempting to write if (!j) here, but if we do this,
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- Solaris 10/x86 "cc -O" miscompiles the code. */
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- if (!i)
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- return 0;
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- /* Unroll the first loop round. k = 0. */
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- if ((unsigned int) j)
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- return ffs ((unsigned int) j);
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- /* Generic loop. */
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- for (k = 1; k < chunk_count - 1; k++)
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- if ((unsigned int) (j >> (k * chunk_bits)) != 0)
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- return k * chunk_bits + ffs ((unsigned int) (j >> (k * chunk_bits)));
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- }
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- /* Last loop round. k = chunk_count - 1. */
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- return (chunk_count - 1) * chunk_bits
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- + ffs ((unsigned int) (j >> ((chunk_count - 1) * chunk_bits)));
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-#endif
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-}
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