Hello everybody, I've finished first processor.
This is a simple 8-bit processor that we will build and learn in the game. It consists of 6000 wires and 1470 objects.

Processor can execute 4 instructions:

1. ADD <n> - Addition <number from 0 to 15>
2. SUB <n> - Subtraction <number from 0 to 15>
3. NOP - No OPeration
4. HLT - Stop the processor

Registers:

• IP - instruction pointer, stores an address of current instruction in RAM;
• IR - instruction register, stores current executable instruction;
• ACC - accumulator register, stores results of ALU;
• Temp - temp register, stores instruction data from IR.

Components:

• RAM - Random Access Memory, 16 bytes;
• Control Unit - controls the processor;
• ALU - Arithmetic Logic Unit, performs math operations: addition and subtraction;
• Clock - used to synchronize the circuit.

1 processor cycle = 22 gaming ticks.
Each instruction is executed in 4 processor cycles.
On average, it executes 1 instruction per second.

This processor is very simple and great for understanding basics such as:

• General logic of the processor;
• Instruction execution, FETCH-DECODE-EXECUTE cycle;
• How memory works;
• Arithmetic and Logic Unit: addition and subtraction;
• How the processor stores numbers: positive and negative;
• Clock signal synchronization;
• Work with assembler.

What next:

• Add new instructions;
• Optimize the architecture;
• Connect a mouse, keyboard and display;
• Start writing simple programs;
• Ideally we need to get close to the 6502 processor.

Now the hardest part: creating articles and levels in the game with detailed explanation of how it all works step by step.