Lanskern Bytecode & Virtual Machine

Lanskern Bytecode & Virtual Machine(refered as LanCode and LanVM) is a bytecode interpreter designed for higher level programming languages. The bytecode is generated by a compiler or assembler and executed by the virtual machine. It's main goal is to make compiled programming languages portable across different platforms.

VM Architecture

The VM uses a custom 16-bit ISA, similar to the x86 and RISC-V. LanVM supports hypervisor calls, for example, VMEXIT and VMMALLOC. The hypervisor is responsible for managing memory and handling exceptions.

Registers

• R0-R4: 16-bit General Purpose Registers(Accumulator, B, C, Destination, Source)
• F: 8-bit Flags register
• SP: 16-bit Stack Pointer
• BP: 16-bit Base Pointer
• IP: 16-bit Instruction Pointer
• IV: 16-bit Interrupt Vector

Memory

The VM has a maximum of 64KB of stack memory(RAM) and program memory. The memory is dynamically allocated. Initially, the VM allocates 1KB of stack memory. A program can allocate more memory using the VMMALLOC instruction. The program should check the zero flag to see if the operation was successful after executing VMMALLOC. To free memory, use the VMFREE instruction and check the zero flag.

Instruction Set

The LanCode instruction set consists of different types of instructions, for example arithmetic operations, memory operations, control flow instructions, etc. The full instruction set is defined in the ISA.md file.

Assembler

LASM is a simple and small assembler for the LanCode language. Currently it supports labels and comments in the assembly code.

Speed

The VM is generally faster than interpreted languages such as Python, with a typical 2-3 times performance boost.

Building

Prerequisites:

• C compiler, such as gcc
• Make
• Linux

Steps:

1. Clone the repository
2. Run make to build the VM. You can use make vm and make asm to build the VM and LASM respectively.

Usage

VM

Run ./bin/lanvm <program_file> to run a program.

LASM

Run ./bin/lasm <input_file> <output_file> to assemble a program.

Contributing

Pull requests are welcome. If you have any suggestions or find any bugs, please open an issue.

License

This project is licensed under the GNU General Public License v3.0 (GPLv3).
You are free to use, modify, and distribute it under the same license terms.

See the LICENSE file for details.