Re: [computer-go] Random

[Don Dailey]

#include <stdio.h>
#include <stdlib.h>
I'm including my code below.   Also, here are my reported times:

Without RDTSC

real    0m1.008s
user    0m0.668s
sys     0m0.004s


With RDTSC

real    0m5.790s
user    0m3.956s
sys     0m0.016s


To turn on or off RDTSC  see the rdtsc_rand line that says, "if (1)"

- Don

----------[ snip ]------------


#define rdtscll(val) \
         __asm__ __volatile__("rdtsc" : "=A" (val))


unsigned long long rdtsc_rand(void);

/******************************************************/
unsigned long long rdtsc_rand(void)
{
 static unsigned long long val=0x0000000011111111ULL;
 unsigned long long new = 0llu;

 if (1) {
   rdtscll(new);
 }

 val ^= (val >> 15) ^ (val << 14) ^ 9 ^ new;

 return val;
}


void kessel()
{
 int                 i;
 unsigned long long  last = 0;
 unsigned long long  cur = 0;

 for (i=100000000; i>0; i--) {
   cur = rdtsc_rand();
   if (i <= 10) {
     printf("%20llu %20lld\n", cur, (int) cur - last);
   }
   last = cur;
 }
}



int main(int argc, char **argv)
{

 kessel();

 return(0);
}


A van Kessel wrote:

I would like to mention that your generator is 64 bit and the other

That is correct.

My timings (Haven't profiled yet):
WITH TSC:
real    0m0.902s
user    0m0.870s
sys     0m0.002s

WITHOUT:
real    0m0.613s
user    0m0.582s
sys     0m0.000s

That's for 100 M random numbers.

And inlining would probably help a lot, too.

AvK
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