#Fantasy Virtual Machine

A 64-bit stack-based virtual machine and its assembler, created for fun.

#Build

FVM includes two parts: the virtual machine and the assembler.

The build the assembler, you need to intall CHICKEN Scheme first. For example, on Arch Linux:

sudo pacman -S chicken

Then install CHICKEN Scheme dependencies:

sudo chicken-install matchable srfi-69 srfi-4

Then run make, which will build both components:

make

If successful, you will see two executables, the virtual machine fvm and the assemblerfvm-as.

#Run

After writing the assembly code (examples can be found in the examples directory), first run the assembler:

./fvm-as input.asm bytecode.bin

This will generate the bytecode file output.bin. Then run the virtual machine:

./fvm bytecode.bin

#Registers

FVM contains 4 registers:

• SP: stack pointer
• BP：base pointer
• PC：program counter
• RV: returned value

There are no general-purpose registers; all operations happen on the stack.

#Opcodes

All opcodes are single-byte, except for immediate value instructions.

The instructions supported by FVM are as follows:

#Register Instructions

sp
0x00
push stack pointer to stack

ssp
0x01
pop a 64-bit number from stack and set stack pointer to it.

bp

sbp

pc

rv

srv

#Immediate Number

imm

#Memory

ld

ld8

ld16

ld32

st

st8

st16

st32

#Stack Operations

dup

pop

swap

over

rot

#Call Frame

#Pseudo-Opcodes