mirror of https://gitee.com/openkylin/linux.git
33 lines
514 B
C
33 lines
514 B
C
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#include <linux/kernel.h>
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#include <linux/module.h>
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/**
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* int_sqrt - rough approximation to sqrt
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* @x: integer of which to calculate the sqrt
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*
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* A very rough approximation to the sqrt() function.
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*/
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unsigned long int_sqrt(unsigned long x)
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{
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unsigned long op, res, one;
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op = x;
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res = 0;
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one = 1 << 30;
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while (one > op)
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one >>= 2;
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while (one != 0) {
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if (op >= res + one) {
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op = op - (res + one);
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res = res + 2 * one;
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}
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res /= 2;
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one /= 4;
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}
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return res;
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}
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EXPORT_SYMBOL(int_sqrt);
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