Virtual CPU Instruction Set

Design goals

• Simple to implement in other programming languages
• Efficient to execute by emulator
• Future extensibility (to support 128-bit data/address width or more)
• Single instruction code for any data/address width
• Register based load-store architecture rather than stack based machine or accumulator based machine

Other interesting instruction sets

CPU	Instruction count	Instruction size [bits]	Data size [bits]	Addressable memory [bits]	Registers
Tiny CPU Instruction Set	22	8-16	8	10	PC, SP, A, X, SR
A Quick Introduction to the ZipCPU Instruction Set	29	32	32	32	R0-R13, PC, CC
MINI-CPU Instruction Set Specification	12	4-12	8	8	PC, ACC, R
Simple Virtual Machine	18	8	32	32	PC, SP, FP
Simple virtual machine which interprets bytecode.	36	16-32	16-32	16-32	IP, FLAGS, R0-R9, SP
VAM Virtual Assembler Machine	58	16-32	16-32	16-32	R0-Rn (IP, SP)
Simple 8-bit Assembler Simulator	60	8	8	8	PC, SP, A, B, C, D
The RiSC-16 Instruction-Set Architecture	8	16	16	16	PC, R0-R7
TOY Machine	16	16	16	8 (256 words)	PC, R0-R15
MU0	8	16	16	12	PC, ACC
LC-3	15	16	16	16	PC, R0-R7
TOY/2 - a minimalist 16 bit CPU	15	16	16	16	PC, A, T
MARIE: An Introduction to a Simple Computer	9	16	16	12	PC, ACC
Building a 4-Bit Computer: The Instruction Set	16	4	4	12	R0-R5, S0, S1, PC, SP, IX, IV, TA
How to create your own virtual machine	35	8	8	16	A, B, X, Y, D
Little Man Computer	10	12	8	8	A
CRISC	32	struct	64	16-64
CHIP-8	35	16	8	12	V0-V15, I
Toy CPU	14	8	8	8	A
8bit virtual machine	28	8	8	8	PC, A, X

External links

• Virtual machine on c2 wiki
• Write your Own Virtual Machine
• Writing a simple 16 bit VM in less than 125 lines of C
• UXN - personal computing stack based on a small virtual machine