cpu

Utilities, world downloads, schematics for my Minecraft Computers and CPUs

First generation

DIKC-8 (summer of 2023)

Working computer, with built-in screen and a limited range of operations. Designed while having basically no knowledge of how computers actually work...

• Program
  • 256B ROM, or 128 2B instructions
  • Reads 1 instruction into a buffer at 10Hz speed
  • 16 possible instructions (1 unused)
  • Conditional jump
• Memory
  • 16 registers
  • 8 "boolean" registers (storing bit by bit)
• I/O
  • Built-in 16x16 screen
• Computing
  • ALU with addition, subtraction, multiplication, division and comparisons
  • Clock stalls during costly operations like multiplication and division
  • Separate LU for boolean logic with the boolean registers
• Misc
  • Word size of 8 bits
  • Limited pipelining
  • 91-tick clock (0.11Hz)
  • Serial observer rom (so not MCHPR compatible)
  • Python simulator

smol DIKC-4 (April 2024)

A small project for a small CPU, which fits in a 16x16x16 area! Unfortunately not Turing-complete, as there was no space to implement conditional branching.

• Program
  • 8B analog ROM, or 8 1B instructions
  • 7 possible instructions (1 unused)
• Memory
  • 3 registers
• I/O: None
• Computing
  • ALU with addition, subtraction. Saves in dedicated buffer for future use.
• Misc
  • Word size of 4 bits
  • The limited number of instructions can be circumvented by not adding a HLT instruction and letting the program loop
  • 50-tick clock (0.2Hz)

DIKC-8 2 (2023 - 2025)

A revamp of the DIKC-8 in every aspect. It had a major focus on speed and pipelining, which actually ended up killing the project. As I wanted to add new features, more components, this speed constraint was an added complexity that made it harder to debug.

Additionally, as I learned more about computer architecture, I became aware of the many design flaws in the DIKC-8 2. This ultimately made me abandon the project and start over, hence the second generation.

• Program
  • 1KB ROM, or 512 2B instructions
  • Reads 1 instruction into a buffer at 10Hz speed
  • 32 possible instructions
  • Conditional and unconditional jump
• Memory
  • 32 registers
  • Buffer for immediate values before writing them to a register
  • 10-deep call stack
• I/O
  • 8 1B ports that can be written to, read from, or pulsed (quickly turn on and off again in one single instruction)
  • Outputted 1B ALU result
• Computing
  • ALU operations are stored in dedicated 1B buffer and comparisons in a 1-bit buffer
  • ALU with addition, subtraction, comparisons, most bitwise operations and bit shifts
  • Bitwise operations possible outside the ALU: set or unset a bit, use a bit as the condition for the next conditional jump
• Misc
  • Word size of 8 bits
  • Serial ROM for compactness, but split into multiple sections for speed
  • For operations like jumps or division, which take multiple cycles, it is possible to run some operations while waiting for the first to finish. For example, LDI ...; JMP ...; NOP can be made faster by running JMP ...; LDI ... instead.
  • 33-tick clock (0.3Hz)

Warning

This computer is nonfunctional and discontinued.
Although I spent a lot of time refining it, the assembly took too much effort and its various issues / oversights made it easier to start over, hence the second generation.

Second generation

PUSSI-8 (2025 - ...)

Born from the ashes of the DIKC-8 2. Made to be better in every way, incorporating some of my fresh knowledge on computer architecture.

The main motivation for its specs was to make it run Tetris, or even a custom operating system.

Note

This computer is currently under creation, most of the following specs are subject to change.

• Program
  • 1KB built-in analog ROM, or 512 2B instructions
  • Support for up to 128KB external rom, or 65K instructions
  • 16B decoded instructions cache
• Memory
  • 8 registers with simulated dual-read. Can be used as pointers.
  • 16B cache, split into 2 modules to implement LRU. Sole interface between the registers and the RAM. Can read and write one address at a time, or in bulk.
  • 256B RAM, stored as serial for compactness
  • 12-deep call stack
• I/O
  • 10 1B readable and writable ports
  • 2 reserved output ports (for the ALU buffer and state register)
  • PC readable from the outside
  • Plug-in external ROM (see ROM section)
• Computing
  • ALU with addition, subtraction, all bitwise operations, bit shifts and barrels
  • Big math units for multiplication and division
  • State register for use in conditional jumps: zero, nonzero, carry, ALU overflow, stack overflow and underflow, constant 1, constant 0
  • Conditional absolute and relative jumps
• Misc
  • Word size of 8 bits
  • 32 possible instructions (1 unused)
  • Most components notice the caller when they are done, to reduce timing errors and make debugging easier
  • Full web emulator

Warning

Just to be clear, DIKC stands for "D_00's Incredible Keyboardless Computer".
Same with PUSSI which means "Powerful Unit for Smart Systems of Information".