mirror of
https://github.com/AltraMayor/f3.git
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751b5a609f
f3brew, f3 block read write, tests block devices
writing and reading blocks directly to devices.
This is a not-functional version of f3brew.
The main contribution of this patch is to reorganize libprobe.{h,c},
so f3brew, and any future application, can reuse the library.
42 lines
614 B
C
42 lines
614 B
C
#include "libutils.h"
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/* Count the number of 1 bits. */
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static int pop(uint64_t x)
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{
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int n = 0;
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while (x) {
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n++;
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x = x & (x - 1);
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}
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return n;
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}
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int ilog2(uint64_t x)
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{
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x = x | (x >> 1);
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x = x | (x >> 2);
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x = x | (x >> 4);
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x = x | (x >> 8);
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x = x | (x >> 16);
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x = x | (x >> 32);
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return pop(x) - 1;
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}
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/* Least power of 2 greater than or equal to x. */
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static uint64_t clp2(uint64_t x)
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{
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x = x - 1;
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x = x | (x >> 1);
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x = x | (x >> 2);
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x = x | (x >> 4);
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x = x | (x >> 8);
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x = x | (x >> 16);
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x = x | (x >> 32);
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return x + 1;
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}
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int ceiling_log2(uint64_t x)
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{
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return ilog2(clp2(x));
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}
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