**Introduction**
Positional popcount in optimised assembler is typically done on SIMD
-ISAs in around 500 lines. Power ISA thanks to `bpermd` can be much
+ISAs in around 500 lines. The implementations are extraordinarily
+complex and very hard to understand. Power ISA thanks to `bpermd` can be much
more efficient: with SVP64 even more so. The reference implementation
showing the concept is below.