diff --git a/OpenCL/types_ocl.c b/OpenCL/types_ocl.c
index c68ab90cc..137f67e09 100644
--- a/OpenCL/types_ocl.c
+++ b/OpenCL/types_ocl.c
@@ -282,6 +282,7 @@ static inline u32x rotl32 (const u32x a, const u32 n)
   return rotate (a, n);
 }
 
+#if CUDA_ARCH >= 350
 static inline u64 rotr64 (const u64 a, const u32 n)
 {
   u32 il;
@@ -309,6 +310,12 @@ static inline u64 rotr64 (const u64 a, const u32 n)
 
   return r;
 }
+#else
+static inline u64 rotr64 (const u64 a, const u32 n)
+{
+  return rotate (a, (u64) 64 - n);
+}
+#endif
 
 static inline u64 rotl64 (const u64 a, const u32 n)
 {
diff --git a/src/shared.c b/src/shared.c
index 71f5972c7..fd8894959 100644
--- a/src/shared.c
+++ b/src/shared.c
@@ -448,13 +448,13 @@ int base32_encode (u8 (*f) (const u8), const u8 *in_buf, int in_len, u8 *out_buf
     out_ptr += 8;
   }
 
-  int out_len = (in_len * 8) / 5;
+  int out_len = (int) (((0.5 + (float) in_len) * 8) / 5); // ceil (in_len * 8 / 5)
 
-  for (int i = 0; i < (7 - (in_len % 7)); i++)
+  while (out_len % 8)
   {
-    out_len++;
-
     out_buf[out_len] = '=';
+
+    out_len++;
   }
 
   return out_len;
@@ -515,13 +515,13 @@ int base64_encode (u8 (*f) (const u8), const u8 *in_buf, int in_len, u8 *out_buf
     out_ptr += 4;
   }
 
-  int out_len = (in_len * 8) / 6;
+  int out_len = (int) (((0.5 + (float) in_len) * 8) / 6); // ceil (in_len * 8 / 6)
 
-  for (int i = 0; i < (3 - (in_len % 3)); i++)
+  while (out_len % 4)
   {
-    out_len++;
-
     out_buf[out_len] = '=';
+
+    out_len++;
   }
 
   return out_len;