Benefits of 65C02 versus 6502

wimoos · Post by **wimoos** » Fri Feb 22, 2019 7:09 am

Here is a short overview of the benefits I experienced of 65C02 code versus 6502 code in my work on WimBasic.

These are massive register savers and used many, many times: (zp) adressing, PHX, PLX, PLY, PHY, SMB, RMB, BBR, BBS, STZ
These are clever and handy but not often applicable: JMP (table,X), BIT #, BIT abs,X, INC A, DEC A, TRB, TSB
I thought I would need BRA often, instead of branch on a known condition, but I never really did.
I could always find a known condition (not the CLV \ BVC

).

All in all the 65C02 version of WimBasic is 189 bytes shorter than the 6502 variant on a total of 8052 bytes.
It is also faster (2-4%), mostly because of not having to save or transfer registers.

Regards,

Wim.