Better support of RDTSC instruction

clock/clock_linux_stubs.c

@@ -28,15 +28,45 @@ clock_linux_get_time_byte(__unit ())
 uint64_t
 clock_linux_get_tick(__unit ())
 {
-  // struct timespec ts;
-  unsigned hi, lo;
+#if defined(___i386__)
+  int64_t ret;
+  __asm__ __volatile__ ("rdtsc" : "=A"(ret));
+  return ret;
+#elif defined(__x86_64__) || defined(__amd64__)
+  uint64_t hi, lo;
   __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
+  return (lo | (hi << 32));
+#elif defined(__powerpc__) || defined(__ppc__)
 
+#if defined(__powerpc64__) || defined(__ppc64__)
+  int64_t tb;
+  __asm__ __volatile__("mfspr %0, 268" : "=r" (tb));
+  return tb;
+#else
+  uint32_t tbl, tbu0, tbu1;
+  __asm__ __volatile__(
+    "mftbu %0\n"
+    "mftbl %1\n"
+    "mftbu %2"
+    : "=r"(tbu0), "=r"(tbl), "=r"(tbu1));
+  tbl &= (int32_t)(tbu0 == tbu1);
+  return (((uint64_t) tbu1 << 32) | ((uint64_t) tbl));
+#endif
+
+#elif defined(__ia64__)
+  int64_t itc;
+  __asm__("mov %0 = ar.itc" : "=r"(itc));
+  return itc;
+#elif defined(__aarch64__)
+  int64_t virtual_timer_value;
+  __asm__ __volatile__("mrs %0, cntvct_el0" : "=r"(virtual_timer_value));
+  return virtual_timer_value;
+#else
+#error A Cycle Timer is not available for your OS and CPU
+#endif
   // XXX(dinosaure): [clock_gettime] costs a lot and are
   // not really precise. [rdtsc] (Read Time Stamp Counter)
   // is more reliable.
-
-  return (((unsigned long long) lo) | (((unsigned long long) hi) << 32));
 }
 
 uint64_t