1 files changed, 80 insertions, 0 deletions

diff --git a/nacl/cpucycles/alpha.c b/nacl/cpucycles/alpha.c
new file mode 100644
index 00000000..ef497999
--- /dev/null
+++ b/nacl/cpucycles/alpha.c
@@ -0,0 +1,80 @@
+/*
+cpucycles/alpha.c version 20060316
+D. J. Bernstein
+Public domain.
+*/
+
+#include <time.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+static long long tod(void)
+{
+  struct timeval t;
+  gettimeofday(&t,(struct timezone *) 0);
+  return t.tv_sec * (long long) 1000000 + t.tv_usec;
+}
+
+static long long rpcc(void)
+{
+  unsigned long long t;
+  asm volatile("rpcc %0" : "=r"(t));
+  return t & 0xffffffff;
+}
+
+static long long firstrpcc;
+static long long firsttod;
+static long long lastrpcc;
+static long long lasttod;
+static double mhz = 0;
+
+static void init(void)
+{
+  firstrpcc = rpcc();
+  firsttod = tod();
+
+  do {
+    lastrpcc = rpcc();
+    lasttod = tod();
+  } while (lasttod - firsttod < 10000);
+
+  lastrpcc -= firstrpcc; lastrpcc &= 0xffffffff;
+  lasttod -= firsttod;
+
+  mhz = (double) lastrpcc / (double) lasttod;
+}
+
+long long cpucycles_alpha(void)
+{
+  double x;
+  long long y;
+
+  if (!mhz) init();
+
+  lastrpcc = rpcc();
+  lasttod = tod();
+
+  lastrpcc -= firstrpcc; lastrpcc &= 0xffffffff;
+  lasttod -= firsttod;
+
+  /* Number of cycles since firstrpcc is lastrpcc + 2^32 y for unknown y. */
+  /* Number of microseconds since firsttod is lasttod. */
+
+  x = (lasttod * mhz - lastrpcc) * 0.00000000023283064365386962890625;
+  y = x;
+  while (x > y + 0.5) y += 1;
+  while (x < y - 0.5) y -= 1;
+
+  y *= 4294967296ULL;
+  lastrpcc += y;
+
+  mhz = (double) lastrpcc / (double) lasttod;
+
+  return firstrpcc + lastrpcc;
+}
+
+long long cpucycles_alpha_persecond(void)
+{
+  if (!mhz) init();
+  return 1000000.0 * mhz;
+}