The thing you'va labelled 'buffer' should be memory, the 'decoder' doesn't actually do anything.

If you're planning to build a computer in TPT, online resources on processor architecture are useful, just scale them down. A LOT. Your memory is WAY to big for any processor on TPT, work on a more compact one.

This is the resource I used.

http://www.instructables.com/id/How-to-Build-an-8-Bit-Computer/

It's probably worth mentioning my resulting CPU followed next to none of this guide, but it helped a lot to create possible ideas for one.

Hope I helped.

Hmmm, http://bit.ly/1sVtuzf

EDIT: On a serious note, 

An ALU can be as simple as a binary adder, or be extremely complex, including comparators, etc. The ALU in my published CPU is just a binary adder with some extra functions.

To INCREMENT. Check the current (first) bit. If it is on, do this for the next bit. Else, turn this bit on.

To ADD, Complete the above steps, checking the bits of the value to add. Alternatively, for a faster adder, you can just logic gates: http://en.wikipedia.org/wiki/Adder_(electronics)

To SUBTRACT, invert the bits, add the value, invert again.

To COMPARE, ask @arK :). Or look here: http://en.wikipedia.org/wiki/Digital_comparator In short, you can just use an X-NOR gate as a basic comparator.

You can have a look at some of the links on this page: http://en.wikipedia.org/wiki/Arithmetic_logic_unit

Real life techniques work well in TPT. Try google. really.

I'm good at TPT electronics but I don't know how to wire it all together so that it responds to input, transfers data properly, and is  compact. How do people make compact wires plz help :/

@msasterisk (View Post)

Forget compact. Use INST or ARAY for performance.

INST is easier to use, ARAY is slightly more compact.

dom2mom could help you, but (no offense to dom2mpm) he's a bit of a hot head now.