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/* Copyright 2014 The ChromiumOS Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* Software emulation for CLZ instruction
*/
#include "common.h"
/**
* Count leading zeros
*
* @param x non null integer.
* @return the number of leading 0-bits in x,
* starting at the most significant bit position.
*/
int __keep __clzsi2(int x)
{
int r = 0;
if (!x)
return 32;
if (!(x & 0xffff0000u)) {
x <<= 16;
r += 16;
}
if (!(x & 0xff000000u)) {
x <<= 8;
r += 8;
}
if (!(x & 0xf0000000u)) {
x <<= 4;
r += 4;
}
if (!(x & 0xc0000000u)) {
x <<= 2;
r += 2;
}
if (!(x & 0x80000000u)) {
x <<= 1;
r += 1;
}
return r;
}
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