diff --git a/cpuinfo.c b/cpuinfo.c
index 1610cb3092..a1bd4f621b 100644
--- a/cpuinfo.c
+++ b/cpuinfo.c
@@ -77,10 +77,10 @@ cpuid(int func) {
 static int64_t
 rdtsc(void)
 {
-  uint64_t i;
+  uint64_t hi, lo;
 #define RDTSC   ".byte 0x0f, 0x31; "
-  __asm__ volatile (RDTSC : "=A"(i) : );
-  return i;
+  __asm__ volatile (RDTSC : "=a"(lo), "=d"(hi) : );
+  return hi << 32 | lo;
 }
 
 static const char*