notiriscent / danilusvm

A small virtual machine written in C

DanilusVM

A small virtual machine written in C

About

Toy virtual machine, written in C, uses Lua 5.2 and SDL (in the future there will be a programming language)

Requirements

Debian-like

make
libsdl2-2.0-0
libsdl2-dev
liblua5.2-0
liblua5.2-dev
clang

Arch-like

make
sdl2
lua52
clang

If you are using a Debian family operating system, you can use this command:

# apt install make libsdl2-2.0-0 libsdl2-dev liblua5.2-0 liblua5.2-dev clang

If you are using an Arch family operating system, you can use this command:

# pacman -S make sdl2 lua52 clang

Build 'n' Run

To compile, use the following command:

$ make

The compiled program will be in ./bin/main

The files of your operating system must be on the path ./FS/* (relative to the ./main file). The entry point is the init.lua file (you can change file system path in vm.cfg)

To run the VM, enter the program directory (./bin by default) and run ./main, or use:

$ make run

Config file

The VM configuration is done via the vm.cfg file.

At the moment you can configure the CPU speed (cpu_clock), the amount of RAM (ram_size), the time after which the system will be killed in case of a dead loop, as well as the path to the file system of VM.

API

gpu - an interface for drawing graphics on the screen.

(at the moment it is not possible to get the screen resolution with Lua, it is 800x600)

gpu.setcolor(number color_rgba) -> nil - sets the drawing color

gpu.getcolor() -> number - returns the current color

gpu.getpixel(number x, number y) -> number- returns the color of the specified pixel

gpu.clear() -> nil - clears the screen by filling it with the currently set color gpu.fill(number x, number y, number w, number h) -> nil - draws a rectangle

gpu.copy(number x, number y, number w, number h, number xo, number yo) -> nil - copies a piece of the screen and shifts it by the specified (ox, oy) number of pixels

gpu.update() -> nil - update screen

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computer - an interface for working with the virtual machine (computer)

computer.gettotal() -> number - returns the total amount of RAM

computer.getused() -> number - returns the amount of used RAM

computer.pushevent(...) -> nil - accepts any numbers and strings, creates an event and adds to the queue

computer.pullevent(number timeout) -> ... - retrieves information about an event by taking it from the event queue (returns all values as a string!) (timeout in ms)

• keydown -> "keydown", string - returns the event name and the scancode. Triggered when a key is pressed on the keyboard

• keyup -> "keyup", string - returns the event name and the scancode. Triggered when a key is released on the keyboard

• (Yes, that's all for now :)

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filesystem - an interface for working with filesystem of VM

filesystem.exists(string path) -> bool - checks if a file exists

filesystem.isdir(string path) -> bool - checks if a folder exists

filesystem.mkdir(string path) -> bool - creates a folder, if successful - returns true

filesystem.size(string path) -> bool, number - returns true if successful and the size of the specified file

filesystem.rmfile(string path) -> bool - deletes the file (or folder) if it is empty, returns true if successful

filesystem.rmdir(string path) -> bool - deletes the folder if it is empty, returns true if successful

filesystem.listdir(string path) -> bool, table - reads a folder and returns true if successful and an array with the names of files and folders

filesystem.rename(string oldname, string newname) -> bool - renames a file, returns true if successful

filesystem.open(string path, string mode) -> bool, number - opens a file, returns true if successful and returns a file descriptor

filesystem.close(number fd) -> bool - closes a file, returns true if successful

filesystem.write(number fd, string data) -> bool - writes data to file, returns true if successful

filesystem.read(number fd, number bytes) -> bool, string - reads a certain number of bytes, returns true and the read bytes if successful

filesystem.seek(number fd, number type, number offset) -> bool - shifts the cursor by a certain number of bytes, the type indicates what to shift relative to

• 1 - set (beginning of file)

• 2 - cursor

• 3 - end (end of file)

filesystem.getpos(number fd) -> bool, number - returns true if successful and the position of the cursor in a file

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Notes:

• if you try while true do end - the VM will be killed after 10 seconds (can be configured in vm.cfg)