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https://github.com/GerbilSoft/zlib-ng.git
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45 lines
1.3 KiB
C
45 lines
1.3 KiB
C
#ifndef X86_BUILTIN_CTZ_H
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#define X86_BUILTIN_CTZ_H
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#if defined(_MSC_VER) && !defined(__clang__)
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#if defined(_M_IX86) || defined(_M_AMD64) || defined(_M_IA64) || defined(_M_ARM) || defined(_M_ARM64)
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#include <intrin.h>
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#ifdef X86_FEATURES
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# include "arch/x86/x86.h"
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#endif
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/* This is not a general purpose replacement for __builtin_ctz. The function expects that value is != 0
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* Because of that assumption trailing_zero is not initialized and the return value of _BitScanForward is not checked
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*/
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static __forceinline unsigned long __builtin_ctz(uint32_t value) {
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#ifdef X86_FEATURES
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if (x86_cpu_has_tzcnt)
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return _tzcnt_u32(value);
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#endif
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unsigned long trailing_zero;
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_BitScanForward(&trailing_zero, value);
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return trailing_zero;
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}
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#define HAVE_BUILTIN_CTZ
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#ifdef _M_AMD64
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/* This is not a general purpose replacement for __builtin_ctzll. The function expects that value is != 0
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* Because of that assumption trailing_zero is not initialized and the return value of _BitScanForward64 is not checked
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*/
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static __forceinline unsigned long long __builtin_ctzll(uint64_t value) {
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#ifdef X86_FEATURES
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if (x86_cpu_has_tzcnt)
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return _tzcnt_u64(value);
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#endif
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unsigned long trailing_zero;
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_BitScanForward64(&trailing_zero, value);
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return trailing_zero;
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}
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#define HAVE_BUILTIN_CTZLL
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#endif
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#endif
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#endif
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#endif
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