# GGBASM (Generating Gameboy Assembler)
[](https://travis-ci.org/rukai/ggbasm) [](https://deps.rs/repo/github/rukai/ggbasm) [](https://crates.io/crates/ggbasm) [](https://docs.rs/ggbasm)
A gameboy assembler as a rust crate library.
Being a library instead of command line application, allows for an elegant combination of:
* raw bytes and instructions generated from rust code
* instructions read from *.asm files.
## RomBuilder
The RomBuilder is the core rust api of GGBASM.
```rust
RomBuilder::new()?
// Starts off in the first rom bank
// A simple example doesnt need to deal with interrupts and jumps, so generate a dummy
.add_basic_interrupts_and_jumps()?
// generate a header from data in the passed header struct
.add_header(header)?
// Add game code via an asm file
.add_asm_file("main.asm")?
// Add an image to the second rom bank
.advance_address(1, 0)?
.add_image("tiles.png", "GraphicsBinary", &colors_map)?
// Consume the RomBuilder and write the rom to disk
.write_to_disk("my_cool_game.gb")?;
```
## Examples
Check out the [examples folder](https://github.com/rukai/ggbasm/tree/master/examples) and [heartacheGB](https://github.com/rukai/HeartacheGB).
## Comparison with [RGBDS](https://github.com/rednex/rgbds)
* RGBDS requires only *.asm files, while GGBASM requires *.asm, and an entire rust crate.
* RGBDS needs to run `RGBDS -o main.obj src/main.asm; rgblink -m game.map -n game.sym -o out.gb main.obj; rgbfix -p 0 -v out.gb` to build the rom, while GGBASM uses `cargo run` to build the rom
* RGBDS uses includes inside the *.asm files, while GGBASM uses rust to insert instructions and raw bytes at the correct location in the rom.
* GGBASM has helper functions for generating bytes such as: png_to_gb_sprite
* RGBDS has its own intel-like syntax, GGBASM syntax uses RGBDS syntax with a few additions. Changes from RGBDS are:
+ hexadecimal can be represented as 0x2a as well as $2a
+ uses `advance_address 0xYYYY` instead of `section "FOO",$HOME[$YY]`