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Fixed bug with square root on i386 #4

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Fixed bug with square root on i386 #4

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35 changes: 2 additions & 33 deletions src/stats.c
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@
#include <time.h>
#include <signal.h>
#include <sys/time.h>
#include <math.h>
#include <netinet/in.h>
#include <pthread.h>

Expand All @@ -57,8 +58,6 @@ static void *clean_thread(void *);
static int lock_sessions(void), unlock_sessions(void),
lock_stats(void), unlock_stats(void);

static unsigned long isqrt(unsigned long) __attribute__ ((const));

int
init_stats(void) {
stats = malloc((statssz = INITIAL_STAT_SZ) * sizeof(unsigned long));
Expand Down Expand Up @@ -465,36 +464,6 @@ stats_var(struct stats_results *results, int percentile) {

unsigned long
stats_std(struct stats_results *results, int percentile) {
return isqrt(stats_var(results, percentile));

}

// Based in code from
// http://www.codecodex.com/wiki/Calculate_an_integer_square_root#C
// It stipulates that content is available under the
// GNU Free Documentation License
static unsigned long
isqrt(unsigned long x)
{
unsigned long op, res, one;

op = x;
res = 0;

// "one" starts at the highest power of four <= than the argument.
one = 1;
while (one < op) one <<= 2;
while (one > op) one >>= 2;

while (one) {
if (op >= res + one) {
op -= res + one;
res += one << 1;
}
res >>= 1;
one >>= 2;
}

return res;
return sqrtl(stats_var(results, percentile));

}