Xi

A hyper-minimal 6-bit Minecraft CPU.

Used Terms

Hexad: 6 bits of data Triad: 3 bits of data

Specifications

• Clock: Pulse every 192 ticks (~0.052 hz)
• Register File: 8 hexads, 1 per register (r0-r7, r0 is tied to 0, r5-r7 are sent to display)
• Instruction Memory: 64 instructions worth (128 hexads)
• Display: 6x3
• Program Counter: 1 hexad

Instructions

Structure

o x (y z / ii) (Each letter corresponds to one triad, ii is the last two triads used for immediate loading.)

Set

Opcode	Assembly	Description
000	ldi rx ii	rx = ii
001	skp __ __ rz	pc += 1 if rz != 0
010	jmp __ ry rz	pc = ry if rz == 0
011	hlt __ __ __	stop clock
100	add rx ry rz	rx = ry + rz
101	sub rx ry rz	rx = ry - rz
110	nor rx ry rz	rx = ~(ry | rz)
111	shr rx ry __	rx = ry >> 1

Example Program (Fibonacci Sequence)

ldi r3 3
ldi r1 0
ldi r2 1
add r5 r1 r2
add r1 r2 r0
add r2 r5 r0
jmp r3 r0