release/src/router/dnscrypt/src/libnacl/cpucycles/celllinux.c

   1 #include <time.h>
   2 #include <stdio.h>
   3 #include <unistd.h>
   4 #include <sys/time.h>
   5 #include <sys/types.h>
   6 #include <spu_mfcio.h>
   7
   8 static long myround(double u)
   9 {
  10   long result = u;
  11   while (result + 0.5 < u) result += 1;
  12   while (result - 0.5 > u) result -= 1;
  13   return result;
  14 }
  15
  16 static long long microseconds(void)
  17 {
  18   struct timeval t;
  19   gettimeofday(&t,(struct timezone *) 0);
  20   return t.tv_sec * (long long) 1000000 + t.tv_usec;
  21 }
  22
  23 static long long timebase(void)
  24 {
  25   unsigned long long result;
  26   result = -spu_read_decrementer();
  27   return 0xffffffff & result;
  28 }
  29
  30 static double cpufrequency = 0;
  31 static long tbcycles = 0;
  32
  33 static double guesstbcycles(void)
  34 {
  35   long long tb0; long long us0;
  36   long long tb1; long long us1;
  37
  38   tb0 = timebase();
  39   us0 = microseconds();
  40   do {
  41     tb1 = timebase();
  42     us1 = microseconds();
  43   } while (us1 - us0 < 10000 || tb1 - tb0 < 1000);
  44   if (tb1 <= tb0) return 0;
  45   tb1 -= tb0;
  46   us1 -= us0;
  47   return (cpufrequency * 0.000001 * (double) us1) / (double) tb1;
  48 }
  49
  50 static void init(void)
  51 {
  52   int loop;
  53   double guess1;
  54   double guess2;
  55
  56   spu_write_decrementer(0xffffffff);
  57
  58   cpufrequency = 3192000000.0;
  59
  60   for (loop = 0;loop < 100;++loop) {
  61     guess1 = guesstbcycles();
  62     guess2 = guesstbcycles();
  63     tbcycles = myround(guess1);
  64     if (guess1 - tbcycles > 0.1) continue;
  65     if (tbcycles - guess1 > 0.1) continue;
  66     if (guess2 - tbcycles > 0.1) continue;
  67     if (tbcycles - guess2 > 0.1) continue;
  68     return;
  69   }
  70   tbcycles = 0;
  71 }
  72
  73 long long cpucycles_celllinux(void)
  74 {
  75   if (!tbcycles) init();
  76   return timebase() * tbcycles;
  77 }
  78
  79 long long cpucycles_celllinux_persecond(void)
  80 {
  81   if (!tbcycles) init();
  82   return cpufrequency;
  83 }