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35 lines
1.4 KiB
C
35 lines
1.4 KiB
C
#ifndef COSMOPOLITAN_LIBC_NEXGEN32E_BSR_H_
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#define COSMOPOLITAN_LIBC_NEXGEN32E_BSR_H_
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#if !(__ASSEMBLER__ + __LINKER__ + 0)
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COSMOPOLITAN_C_START_
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int _bsr(int) pureconst;
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int _bsrl(long) pureconst;
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int _bsrll(long long) pureconst;
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#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
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#ifdef __x86_64__
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int _bsr128(uint128_t) pureconst;
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#define _bsr(u) \
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({ \
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unsigned BiTs; \
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asm("bsr\t%0,%0" : "=r"(BiTs) : "0"((unsigned)(u)) : "cc"); \
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BiTs; \
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})
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#define _bsrl(u) \
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({ \
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unsigned long BiTs; \
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asm("bsr\t%0,%0" : "=r"(BiTs) : "0"((unsigned long)(u)) : "cc"); \
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(unsigned)BiTs; \
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})
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#define _bsrll(u) _bsrl(u)
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#else
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#define _bsr(x) (__builtin_clz(x) ^ (sizeof(int) * CHAR_BIT - 1))
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#define _bsrl(x) (__builtin_clzl(x) ^ (sizeof(long) * CHAR_BIT - 1))
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#define _bsrll(x) (__builtin_clzll(x) ^ (sizeof(long long) * CHAR_BIT - 1))
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#endif
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#endif
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COSMOPOLITAN_C_END_
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#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
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#endif /* COSMOPOLITAN_LIBC_NEXGEN32E_BSR_H_ */
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