Merge pull request #12 from aCube1/readme

Add README file.

README.md

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+# Yet another Chip-8 ~~emulator~~ interpreter.
+
+## History
+Chip-8 was a virtual machine/programming language developed by RCA engineer **Joseph Weisbecker** in 1977 for the **COSMAC VIP** microcomputer. It was intended as a simple way to make small programs and games for the computer. Chip-8 soon spread to the other computers, like **Finnish Telmac 1800**, the Australian **DREAM 6800**, **ETI-660** and **MicroBee**, and the Canadian **ACE VDU**.
+
+## Technical information
+The original Chip-8 was designed with the following specifications:
+
++ Memory: Chip-8 has direct access to up 4KB RAM
++ Display: 64x32 pixels monochrome, ie. Black or White
++ Keypad: 16 keys, labelled `0` through `F`, and were arranged in a 4x4 grid.
++ A _program counter_, often called "PC", which point at the current instruction in memory
++ One 16-bit _index register_ called "I" which is used to point at locations in memory
++ A _stack_ for 16-bit addresses, which is used to call subroutines/functions and return from them
++ An 8-bit _delay timer_ which is decremented at a rate of 60Hz (60 times per second) until reaches 0
++ An 8-bit _sound timer_ which functions like the delay timer, but which also gives off a beeping sound as long as it's not 0
++ 16 8-bit(one byte) general-purpose _variable_ registers numbered `0` through `F` hexadecimal, ie. 0 through 15 in decimal, called `V0` through `VF`
+	- `VF` is also used as a _flag register_; many instructions will set it to either `1` or `0` based on some rule, for example using it as a carry flag
+
+## Building
+### Requirements
++ SDL2:
+	- Minimum version required: 2.24.2
+	- Required for rendering and input management.
++ CMake:
+	- Minimum version requiered: 3.21
+	- Required for automatic build.
+
+### Procedures
+### Linux
+For building, you can use this procedure:  
+```
+$ mkdir build
+$ cmake -B build -DCMAKE_BUILD_TYPE=Release
+$ cmake --build build
+```
+
+### Windows
+<sub>***Note***: Not tested, for while, there is no build procedure.</sub>
+
+### Running
+### Linux
+After building with above procedure, the binary will be located in `build/bin/` directory.
+Run the program using:
+`$ ./build/bin/Chip8 <path-to-rom>`
+
+<sub>There's some test roms located in `roms` directory, you can use them. :)</sub>
+
+### Windows
+I don't know.
+
+## Command-line arguments
+| long   | short | value | description                             |
+|--------|-------|-------|-----------------------------------------|
+| clock  |   c   |  int  | Set cpu clock speed(0-1000).            |
+| width  |       |  int  | Set window width to desired resolution  |
+| height |       |  int  | Set window height to desired resolution |
+| help   |   h   |       | Show help message and then exits.       |
+| vesbose|   v   |       | Enable log output on terminal.          |
+| quiet  |   q   |       | Disbale log ouput on terminal.          |
+
+<sub>***Note***: For while, the cpu screen will be stretched to the current resolution.</sub>
+
+## Controls:
+### Keyboard (This is the default keymap)
+`1` `2` `3` `4`  
+`Q` `W` `E` `R`  
+`A` `S` `D` `F`  
+`Z` `X` `C` `V`
+
+### COSMAC VIP Keypad
+`1` `2` `3` `C`  
+`4` `5` `6` `D`  
+`7` `8` `9` `E`  
+`A` `0` `B` `F`
+
+## TODOs
+- [ ] Graphical user interface.
+- [ ] Keyboard shortcuts for opening, reseting and exiting the emulator.
+
+## Roms
++ [Revival Studio's Chip-8 Program Pack](https://github.com/kripod/chip8-roms)
+
+## References
++ [Cowgod's Chip-8 Technical Reference v1.0](http://devernay.free.fr/hacks/chip8/C8TECH10.HTM)
++ [Tobias V.Langhoff](https://tobiasvl.github.io/blog/write-a-chip-8-emulator)
++ [Chip-8 Extensions and compatibility](https://chip-8.github.io/extensions)
++ [Chip-8 Test Suite](https://github.com/Timendus/chip8-test-suite)
+
+## Contributing
+Anyone is welcome to contribute!
+
+## License
+This project is licensed under the MIT license, so you are free to do almost everything you want.