4-Bit Calculator with Decimal I/O

Pixilation's picture
Build image: 
In-game name (NO VISITORS! Must be LEARNER rank or higher!): 
Builder name(s) and current ranks: 
CubeAnimation: Learner
Creation location: 
257 232 -135
Machine Features: 
This is a calculator that can add, subtract and multiply numbers from 0-15. It contains a 4-bit CCA, a 4-bit BCS and a 4-bit sequential multiplier using the 4-bit CCA. (CCA and BCS are my design).
How To Use: 
Press the buttons on the IO to select your A and B inputs, A being on the top and B being below. When doing subtraction, it is *always* A - B, and it can handle negatives and will display their positive equivalents along with a lamp displaying it's "sign" (positive or negative). Then select your operand, being addition, subtraction or multiplication and wait for answer.
Request status: 
Not approved



  • The interface has no feedback on which numbers are currently selected same for the operation.
  • I am not sure how to say it, but I would say the output is base max/infinity since I does not separate by 10's, you loose potential to show off there.
  • Inputs are okay, its understand able to not separate by 10's there.
  • Its difficult to see the lamps when they are 1 block behind the border blocks (at least for the two left).


  • The overflow lamp is always the same for all operations, but seems to be wrong with subtraction mode. Also it has an odd "error-text" maybe tell why inputs are ":("
  • Multiplication could have been 8-bit output which would underline the 10's separation for the output.
  • On overflow disable the output or just turn on all lamps. :)


  • Seems to work fine else, I am not a CCA pro, but I can't detect an issue there.
  • Results are also okay, besides the cases stated above.
  • The multiplication part is conditional not sequential. (You said that in the description.)

All in all works, could have much improvement on the interface, but the main issues are the 4-bit-output and the non-8-bit multiplier, as well as the overflow indicator.

-> You can improve the given points and do the PR again.

By Ecconia