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Now I guess I need to know what the binary number is for each individual key on the keypad, so that I can then "mask" them with the "AND" operation? I was given "right" and "start". LDA button_state AND #%10000000 ; check high bit (right) BNE right_is_down LDA...

"Atari Roots", I believe, is a great book for a beginner (like myself). It doesn't lay on too much extra tech stuff. Just plain english, easy to undertsand. I found the web calculator, very helpful for converting between hex and binary numbers. http://www.easycalculation.com/hex-converter....

Thanks for the help, really appreciate it. I understand this now: updatejoy: ; first, strobe the joypad LDA #1 STA $4016 LDA #0 STA $4016 ; now we're going to loop 8 times (once for each button), and ; rotate each button's status into our button_state variable LDX #$08 ; set X to 8 (the number of ti...

Almost. What was already in button_state on the previous run through the loop? Or to put it another way, "shifting all the bits" of what? I thought that "ROR button_state" meant that we perform ROR on the number in the accumator after "LSR A", and then store the result...

LDX #$08 ; set X to 8 (the number of times we want to loop) joyloop: LDA $4016 ; get button state LSR A ; shift it into the C flag ROR button_state ; rotate C flag into our button_state variable DEX ; decrement X (our loop counter) BNE joyloop ; jump back to our loop until X is zero Just wondering ...

When you say "what you actually get is $40 if the button is not pressed, and $41 if the button is pressed." Those hex numbers are being stored in the accumulator? Yes. You get some of the bits from the controller circuitry, and you get some of the bits left over from the last byte of the ...

Thanks a lot for your help. This is a lot fancier than what I've seen. I think I'm understanding most of what you described. I have to digest it. When you say "what you actually get is $40 if the button is not pressed, and $41 if the button is pressed." Those hex numbers are being stored i...

Hi, This code was cut and pasted from "Rwin's" "Jumpy" program which just displayed a little character that jumped up and down and could be moved left and right with the keypad. I was only interested in the key reading section. I left out the sub routines. That's where I'll be ad...

Each emulator I have ever seen have fully configurable buttons, including the direction keys, which can be substitued by any keyboard keys or joypad buttons you want. Most emulators use the arrow keys by default for the directionnal arrows, but maybe your emulator does require you to specify all jo...

sweet. someone used it!!

anyway, send me a message on aim or look for me in the #nesdev channel if you wanna collab with another noob. i'm sure i'd pay a lot more attention and learn faster with an extra person working with me.

Sounds good, would be very helpful.

Thanks,
Tony

Can any one help? I read the docs but don't understand them. Hi, This is a relatively old post but I'm also just getting started. Check out this archive of free e-books on machine language (assembly language). Atari Roots is a good one. http://www.atariarchives.org/ Also the C64 manual chapter 5 ha...

I am just starting to explore working with the NES, I have no previous programming experience. So I am using nesasm which is working out nice. I tried to load a rom which is supposed to move a little jumping guy (character) left and right in jnes and noticed the arrow keys on my PC don't do anything...