A long time ago on the 6502 I was trying to figure out how to quickly multiply by 3 in assembly and I came up with:
1. Shift-left
2. Add original value
For multibyte values use rotate left which carries, and do the rotates from LSB to MSB. Then clear carry, then do the adds from LSB to MSB with carries. Should work for any word size.
Ofc I was a teenager but this seemed clever and simple to me.
Was (am) I just missing something?
This is covered in the article. See the section "Implementing a fast ×3 circuit with carry lookahead"
I don't know how big your .gitignore must be when trying to use a tool that wants to own every file and directory to manage your /home but if that works for you, more power to ya