6507 Opcodes Crossword Puzzle

[jdrose]

Hello,

 

I created a crossword puzzle of 6507 opcodes. Figured it would be a fun way for beginners to get themselves aquainted with the instruction set of the 6507 microprocessor.

 

Hint: I used the UMC datasheet for my reference but the MOS and Rockwell datasheets use the exact same opcodes and instruction definitions.

 

Also note that I left out from the puzzle the CLI, RTI, SEI* opcodes because I am not sure they have a practical application in the VCS 2600 environment. But mostly because it made everything fit together in the puzzle a little easier.

 

I'll post the solution in my content next week.

 

Enjoy.

 

 

* It is a good idea to execute a SEI at the beginning of your 6507 code just to be sure.

[eshu]

SEI and CLI gives you an extra bit of storage - things are that tight on the 2600 that it's actually handy!

[ClausB]

Nice puzzle!

 

RTI is used with BRK for an often-called subroutine, saving 2 bytes per call. Joe Decuir did this in Video Olympics for a nybble-swapper subroutine. See http://www.atariage....t/#entry2533650