diff --git a/examples_ptx/radixSort/radixSort.cpp b/examples_ptx/radixSort/radixSort.cpp
index d6a21c79..ba09066b 100644
--- a/examples_ptx/radixSort/radixSort.cpp
+++ b/examples_ptx/radixSort/radixSort.cpp
@@ -30,24 +30,36 @@ static inline void progressbar (unsigned int x, unsigned int n, unsigned int w =
   cout << "]\r" << flush;
 }
 
+struct Key
+{
+  int32_t key,val;
+};
+
 int main (int argc, char *argv[])
 {
   int i, j, n = argc == 1 ? 1000000 : atoi(argv[1]), m = n < 100 ? 1 : 50, l = n < 100 ? n : RAND_MAX;
   double tISPC1 = 0.0, tISPC2 = 0.0, tSerial = 0.0;
-  unsigned int *keys = new unsigned int [n];
-  unsigned int *keys_orig = new unsigned int [n];
+  Key *keys = new Key [n];
+  Key *keys_orig = new Key [n];
+  unsigned int *keys_gold = new unsigned int [n];
   
   srand48(rtc()*65536);
 
 #pragma omp parallel for
   for (int i = 0; i < n; i++)
-    keys[i] = 10*i; //drand48() * (1<<30);
+  {
+    keys[i].key = drand48() * (1<<30);
+//    keys[i].val = i;
+  }
 
   std::random_shuffle(keys, keys + n);
 
 #pragma omp parallel for
   for (int i = 0; i < n; i++)
+  {
+    keys_gold[i] = keys[i].key;
     keys_orig[i] = keys[i];
+  }
     
   ispcSetMallocHeapLimit(1024*1024*1024);
 
@@ -55,9 +67,9 @@ int main (int argc, char *argv[])
 
   for (i = 0; i < m; i ++)
   {
-    ispcMemcpy(keys, keys_orig, n*sizeof(unsigned int));
+    ispcMemcpy(keys, keys_orig, n*sizeof(Key));
     reset_and_start_timer();
-    ispc::radixSort(n, (int*)keys);
+    ispc::radixSort(n, (int64_t*)keys);
     tISPC2 += get_elapsed_msec();
     if (argc != 3)
         progressbar (i, m);
@@ -67,12 +79,9 @@ int main (int argc, char *argv[])
 
   printf("[sort ispc + tasks]:\t[%.3f] msec [%.3f Mpair/s]\n", tISPC2, 1.0e-3*n*m/tISPC2);
 
-  std::sort(keys_orig, keys_orig + n);
-#if 0
-  std::sort(keys, keys + n);
-#endif
+  std::sort(keys_gold, keys_gold + n);
   for (int i = 0; i < n; i++)
-    assert(keys[i] == keys_orig[i]);
+    assert(keys[i].key == keys_gold[i]);
 
 
 #if 0
@@ -101,5 +110,6 @@ int main (int argc, char *argv[])
 
   delete keys;
   delete keys_orig;
+  delete keys_gold;
   return 0;
 }
diff --git a/examples_ptx/radixSort/radixSort.ispc b/examples_ptx/radixSort/radixSort.ispc
index 5d092ac8..4e2a7452 100644
--- a/examples_ptx/radixSort/radixSort.ispc
+++ b/examples_ptx/radixSort/radixSort.ispc
@@ -1,9 +1,11 @@
 #define NUMBITS 8
 #define NUMDIGITS (1<<NUMBITS)
 
+typedef int64 Key;
+
 task
 void countPass(
-    const uniform int keysAll[],
+    const uniform Key keysAll[],
     const uniform int bit,
     const uniform int numElements,
     uniform int countsAll[],
@@ -15,7 +17,7 @@ void countPass(
 
   const uniform int mask = (1 << NUMBITS) - 1;
 
-  const uniform int * uniform keys =   keysAll + blockIdx*blockDim;
+  const uniform Key * uniform keys =   keysAll + blockIdx*blockDim;
   uniform int * uniform     counts = countsAll + blockIdx*NUMDIGITS;
   const uniform int           nloc = min(numElements - blockIdx*blockDim, blockDim);
 
@@ -47,8 +49,8 @@ void countPass(
 
 task
 void sortPass(
-    uniform int keysAll[],
-    uniform int sorted[],
+    uniform Key keysAll[],
+    uniform Key sorted[],
     uniform int bit,
     uniform int numElements,
     uniform int digitOffsetsAll[],
@@ -67,7 +69,7 @@ void sortPass(
 #endif
 
   const uniform int keyIndex = blockIdx * blockDim;
-  uniform int * uniform keys = keysAll + keyIndex;
+  uniform Key * uniform keys = keysAll + keyIndex;
   uniform int * uniform digitOffsets = digitOffsetsAll + blockIdx*NUMDIGITS;
   const uniform int nloc = min(numElements - keyIndex, blockDim);
 
@@ -96,8 +98,12 @@ void sortPass(
     }
     else
     {
-#if 1 //def __NVPTX__
-      rel = atomic_add_global(&localCounts[key],1);
+#ifdef __NVPTX__
+      /* buf fix, somehow atomic w/o branching fails */
+      if (programIndex < 16)
+        rel = atomic_add_global(&localCounts[key],1);
+      else
+        rel = atomic_add_global(&localCounts[key],1);
 #else
       rel = atomic_add_local(&localCounts[key],1);
 #endif
@@ -215,7 +221,7 @@ static uniform int * uniform partialSum;
 static uniform int * uniform prefixSum;
 
 static uniform int numElementsBuf = 0;
-static uniform int * uniform bufKeys;
+static uniform Key * uniform bufKeys;
 
 export void radixSort_alloc(const uniform int n)
 {
@@ -268,7 +274,7 @@ export void radixSort_free()
 
 export void radixSort(
     const uniform int numElements,
-    uniform int keys[])
+    uniform Key keys[])
 {
 #ifdef __NVPTX__
   assert((numBlocks & 3) == 0);  /* task granularity on Kepler is 4 */
@@ -279,7 +285,7 @@ export void radixSort(
   if (numElementsBuf == 0)
   {
     numElementsBuf = numElements;
-    bufKeys = uniform new uniform int[numElementsBuf];
+    bufKeys = uniform new uniform Key[numElementsBuf];
   }
 
   const uniform int blockDim  = (numElements + numBlocks - 1) / numBlocks;
@@ -319,7 +325,7 @@ export void radixSort(
           sharedCounts);
     sync;
 
-    uniform int * uniform tmp = keys;
+    uniform Key * uniform tmp = keys;
     keys = bufKeys;
     bufKeys = tmp;
   }