1 files changed, 18 insertions, 0 deletions
diff --git a/target-arm/helper-a64.c b/target-arm/helper-a64.c
index e4c534640e..cccaac6230 100644
--- a/target-arm/helper-a64.c
+++ b/target-arm/helper-a64.c
@@ -49,3 +49,21 @@ uint64_t HELPER(clz64)(uint64_t x)
 {
     return clz64(x);
 }
+
+uint64_t HELPER(rbit64)(uint64_t x)
+{
+    /* assign the correct byte position */
+    x = bswap64(x);
+
+    /* assign the correct nibble position */
+    x = ((x & 0xf0f0f0f0f0f0f0f0ULL) >> 4)
+        | ((x & 0x0f0f0f0f0f0f0f0fULL) << 4);
+
+    /* assign the correct bit position */
+    x = ((x & 0x8888888888888888ULL) >> 3)
+        | ((x & 0x4444444444444444ULL) >> 1)
+        | ((x & 0x2222222222222222ULL) << 1)
+        | ((x & 0x1111111111111111ULL) << 3);
+
+    return x;
+}