There's a lot that can be improved in the code, such as just using FOR...TO...STEP would be much faster.
In general, this is a routine that is super easy to write in 6502 assembly. Most magazine BASIC games had something like that, with a few such routines that were POKEd in memory at startup. Several were written in a relocatable fashion so that they could be copied easily from one game to the next.
In general, this is a routine that is super easy to write in 6502 assembly. Most magazine BASIC games had something like that, with a few such routines that were POKEd in memory at startup. Several were written in a relocatable fashion so that they could be copied easily from one game to the next.