I love reading intricate software hacking articles like this. I think this is something Brian Casey would enjoy. 🙂
Originally shared by Greg Kroah-Hartman
Another on in the theme of “great low-level software hacks”.
This sentence is the best:
The sax instruction is a mix of sta and stx; it tries to write the contents of both A and X to memory, and due to the NMOS process used to manufacture the 6502, zeroes are stronger than ones, so bus contentions resolve into bitwise-and operations.
Relying on the processor manufacturing method to create custom op codes and then exploit them in very useful ways is amazing stuff.
http://www.linusakesson.net/programming/gcr-decoding/index.php
That was an interesting read
That was great! It really brought back memories of working with a C-64. What a fun machine that was. I remember manually editing sectors on floppy disks to hack special abilities into my characters in games, and reading the incredibly dense BASIC implementation. My own 6502 code was never quite so inventive, but I learned a lot. Thanks for sharing.