diff --git a/src/bits.c b/src/bits.c
index b00293c..a3aa4c9 100644
--- a/src/bits.c
+++ b/src/bits.c
@@ -27,6 +27,7 @@ static int fwrite_all(const void* _buf, size_t sz, size_t num, FILE* out)
 static void pbits(char out[restrict 8], unsigned char byte, const char bit[static 2])
 {
 	for(register int i=8; i --> 0; byte >>= 1) *out++=((int)bit[byte & 1]);
+	//TODO: In explicitly threaded version, we can use an atomic (atomic.h) 64-bit integer `store()` to output those 8 bytes in `out`, which will be re-cast as `uint64_t out[restrict 1]`
 }
 
 static inline int check(int val, const char* msg)