added cuda helpers

examples_ptx/nvcc_helpers.cu

@@ -0,0 +1,16 @@
+#include "ispc_malloc.h"
+
+#ifndef _CUDA_
+#error "Something went wrong..."
+#endif
+
+void ispc_malloc(void **ptr, const size_t size)
+{
+  cudaMallocManaged(ptr, size);
+}
+void ispc_free(void *ptr)
+{
+  cudaFree(ptr);
+}
+
+