33 lines
555 B
C++
33 lines
555 B
C++
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/*
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Copyright (c) 2013 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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namespace lean {
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unsigned log2(unsigned v) {
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unsigned r = 0;
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if (v & 0xFFFF0000) {
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v >>= 16;
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r |= 16;
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}
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if (v & 0xFF00) {
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v >>= 8;
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r |= 8;
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}
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if (v & 0xF0) {
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v >>= 4;
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r |= 4;
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}
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if (v & 0xC) {
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v >>= 2;
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r |= 2;
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}
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if (v & 0x2) {
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v >>= 1;
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r |= 1;
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}
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return r;
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}
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}
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