1 files changed, 95 insertions, 0 deletions

diff --git a/nacl/cpucycles/powerpccpuinfo.c b/nacl/cpucycles/powerpccpuinfo.c
new file mode 100644
index 00000000..b70c745a
--- /dev/null
+++ b/nacl/cpucycles/powerpccpuinfo.c
@@ -0,0 +1,95 @@
+#include <time.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include "osfreq.c"
+
+static long myround(double u)
+{
+  long result = u;
+  while (result + 0.5 < u) result += 1;
+  while (result - 0.5 > u) result -= 1;
+  return result;
+}
+
+static long long microseconds(void)
+{
+  struct timeval t;
+  gettimeofday(&t,(struct timezone *) 0);
+  return t.tv_sec * (long long) 1000000 + t.tv_usec;
+}
+
+static int tbshift = 0;
+
+static long long timebase(void)
+{
+  unsigned long high;
+  unsigned long low;
+  unsigned long newhigh;
+  unsigned long long result;
+  asm volatile(
+    "7:mftbu %0;mftb %1;mftbu %2;cmpw %0,%2;bne 7b"
+    : "=r" (high), "=r" (low), "=r" (newhigh)
+  );
+  result = high;
+  result <<= 32;
+  result |= low;
+  return result >> tbshift;
+}
+
+static double cpufrequency = 0;
+static long tbcycles = 0;
+
+static double guesstbcycles(void)
+{
+  long long tb0; long long us0;
+  long long tb1; long long us1;
+
+  tb0 = timebase();
+  us0 = microseconds();
+  do {
+    tb1 = timebase();
+    us1 = microseconds();
+  } while (us1 - us0 < 10000 || tb1 - tb0 < 1000);
+  if (tb1 <= tb0) return 0;
+  tb1 -= tb0;
+  us1 -= us0;
+  return (cpufrequency * 0.000001 * (double) us1) / (double) tb1;
+}
+
+static void init(void)
+{
+  int loop;
+  double guess1;
+  double guess2;
+
+  cpufrequency = osfreq();
+  if (!cpufrequency) return;
+
+  for (tbshift = 0;tbshift < 10;++tbshift) {
+    for (loop = 0;loop < 100;++loop) {
+      guess1 = guesstbcycles();
+      guess2 = guesstbcycles();
+      tbcycles = myround(guess1);
+      if (guess1 - tbcycles > 0.1) continue;
+      if (tbcycles - guess1 > 0.1) continue;
+      if (guess2 - tbcycles > 0.1) continue;
+      if (tbcycles - guess2 > 0.1) continue;
+      return;
+    }
+  }
+  tbcycles = 0;
+}
+
+long long cpucycles_powerpccpuinfo(void)
+{
+  if (!tbcycles) init();
+  return timebase() * tbcycles;
+}
+
+long long cpucycles_powerpccpuinfo_persecond(void)
+{
+  if (!tbcycles) init();
+  return cpufrequency;
+}