mirror of https://github.com/tidwall/tile38.git
25 lines
630 B
Go
25 lines
630 B
Go
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// +build amd64,go1.6
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package geohash
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// useAsm flag determines whether the assembly version of EncodeInt will be
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// used. By Default we fall back to encodeInt.
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var useAsm bool
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// cpuid executes the CPUID instruction to obtain processor identification and
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// feature information.
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func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
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// hasBMI2 returns whether the CPU supports Bit Manipulation Instruction Set
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// 2.
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func hasBMI2() bool {
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_, ebx, _, _ := cpuid(7, 0)
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return ebx&(1<<8) != 0
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}
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// init determines whether to use assembly version by performing CPU feature
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// check.
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func init() {
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useAsm = hasBMI2()
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}
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