2 ms·
Someone trying to minimise gate counts (a full barrel-shifter is an N squared sort of thing) People forget that RISC comes out of researchers doing analysis of
by Taniwha 7y ago
Someone trying to minimise gate counts (a full barrel-shifter is an N squared sort of thing)
People forget that RISC comes out of researchers doing analysis of instruction use, and removing stuff you don't use much - if you can bump the clock speed by 5% by halving the size of a full barrel-shifter then you can execute more instructions per second even if you have to use 3 to do a rotate
- sifar 7y agoROT (and shifts) is N log N. Look at shuffle networks. If you have shift operations in the core, their is no reason you cannot have a ROTATE operation. It doesn't add much additional HW.
- Taniwha 7y agoit adds to gate delays (especially when N is 128 - a 128 fan in is pretty expensive in space and time)