New 6502 language module for Ghidra.

New stuff compared to the standard 6502 support:

• remove default memory block stuff (not useful for me)
• 65c02 instructions support
• minor fixes to the opcode descriptions (unclear this makes a big difference)

Probably coming eventually:

• Rockwell 65c02 instructions
• WDC 65c02 instructions
• NMOS undocumented instructions
• other improvements when/if I figure stuff out...

To install, copy 6502_2 from the dist folder in the repo to Ghidra/Processors/ in your Ghidra folder. (There might be a way to make Ghidra use it in situ, but I couldn't find one.)

The CPUs come up as 6502/CMOS and 6502/NMOS in the languages list. (6502/default is the spec that comes with Ghidra.)

The default memory map has two regions corresponding to zero page and stack. Use Window > Memory Map to add additional regions corresponding to whatever other areas don't overlap your binary. This isn't very slick but I haven't figured out how to make it usefully nicer.

Prerequisites:

• all the stuff you need to run Ghidra
• Apache Ant - I used ver 1.10.5

Tested on OS X.

make GHIDRA=<<path to Ghidra>>

The default value for GHIDRA is $HOME/ghidra_9.0.

The Makefile builds everything, rebuilds the dist/6502_2 folder, and also copies it to $GHIDRA/Ghidra/Processors/, to make it easier to iterate on.

It seems you have to restart Ghidra after making any change.