release/src/router/dnscrypt/src/libnacl/cpucycles/powerpccpuinfo.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 "osfreq.c"
   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 int tbshift = 0;
  24
  25 static long long timebase(void)
  26 {
  27   unsigned long high;
  28   unsigned long low;
  29   unsigned long newhigh;
  30   unsigned long long result;
  31   asm volatile(
  32     "7:mftbu %0;mftb %1;mftbu %2;cmpw %0,%2;bne 7b"
  33     : "=r" (high), "=r" (low), "=r" (newhigh)
  34   );
  35   result = high;
  36   result <<= 32;
  37   result |= low;
  38   return result >> tbshift;
  39 }
  40
  41 static double cpufrequency = 0;
  42 static long tbcycles = 0;
  43
  44 static double guesstbcycles(void)
  45 {
  46   long long tb0; long long us0;
  47   long long tb1; long long us1;
  48
  49   tb0 = timebase();
  50   us0 = microseconds();
  51   do {
  52     tb1 = timebase();
  53     us1 = microseconds();
  54   } while (us1 - us0 < 10000 || tb1 - tb0 < 1000);
  55   if (tb1 <= tb0) return 0;
  56   tb1 -= tb0;
  57   us1 -= us0;
  58   return (cpufrequency * 0.000001 * (double) us1) / (double) tb1;
  59 }
  60
  61 static void init(void)
  62 {
  63   int loop;
  64   double guess1;
  65   double guess2;
  66
  67   cpufrequency = osfreq();
  68   if (!cpufrequency) return;
  69
  70   for (tbshift = 0;tbshift < 10;++tbshift) {
  71     for (loop = 0;loop < 100;++loop) {
  72       guess1 = guesstbcycles();
  73       guess2 = guesstbcycles();
  74       tbcycles = myround(guess1);
  75       if (guess1 - tbcycles > 0.1) continue;
  76       if (tbcycles - guess1 > 0.1) continue;
  77       if (guess2 - tbcycles > 0.1) continue;
  78       if (tbcycles - guess2 > 0.1) continue;
  79       return;
  80     }
  81   }
  82   tbcycles = 0;
  83 }
  84
  85 long long cpucycles_powerpccpuinfo(void)
  86 {
  87   if (!tbcycles) init();
  88   return timebase() * tbcycles;
  89 }
  90
  91 long long cpucycles_powerpccpuinfo_persecond(void)
  92 {
  93   if (!tbcycles) init();
  94   return cpufrequency;
  95 }