# A Dynamic assembler written in Rust for Rust.
The purpose of this tool is to ease the creation of programs that require run-time assembling.
It is compatible with stable `rustc` 1.77 and higher.
[](https://github.com/CensoredUsername/dynasm-rs/actions/workflows/Build_and_test.yml)
[](https://crates.io/crates/dynasm)
`##dynasm-rs` on irc.libera.chat
## Features
- Fully integrated in the Rust toolchain, no other tools necessary.
- The assembly is optimized into a series of `Vec.push` and `Vec.extend` statements.
- Errors are almost all diagnosed at compile time in a clear fashion.
- Write the to be generated assembly inline in nasm-like syntax using a simple macro.
## Documentation
[Documentation](https://CensoredUsername.github.io/dynasm-rs/language/index.html).
[Release notes](https://github.com/CensoredUsername/dynasm-rs/blob/master/doc/releasenotes.md).
## Architecture support
- Supports the x64/x86 instruction sets in long and protected mode with every AMD/Intel/VIA extension except for AVX-512.
- Supports the aarch64 instruction set up to ARMv8.4 except for SVE instructions. The development of this assembler backend has been generously sponsored by the awesome folks at [Wasmer](https://github.com/wasmerio/wasmer)!
- Supports the riscv32 and riscv64 instruction sets, with many extensions. The development of these assembler backends was sponsored by [Wasmer](https://github.com/wasmerio/wasmer) as well!
## Example
```rust
use dynasmrt::{dynasm, DynasmApi, DynasmLabelApi};
use std::{io, slice, mem};
use std::io::Write;
fn main() {
let mut ops = dynasmrt::x64::Assembler::new().unwrap();
let string = "Hello World!";
dynasm!(ops
; .arch x64
; ->hello:
; .bytes string.as_bytes()
);
let hello = ops.offset();
dynasm!(ops
; .arch x64
; lea rcx, [->hello]
; xor edx, edx
; mov dl, BYTE string.len() as _
; mov rax, QWORD print as _
; sub rsp, BYTE 0x28
; call rax
; add rsp, BYTE 0x28
; ret
);
let buf = ops.finalize().unwrap();
let hello_fn: extern "win64" fn() -> bool = unsafe { mem::transmute(buf.ptr(hello)) };
assert!(hello_fn());
}
pub extern "win64" fn print(buffer: *const u8, length: u64) -> bool {
io::stdout()
.write_all(unsafe { slice::from_raw_parts(buffer, length as usize) })
.is_ok()
}
```
## Background
This project is heavily inspired by [Dynasm](http://luajit.org/dynasm.html)
## Sponsorship
The development of the Aarch64 assembler backend has been sponsored by [Wasmer](https://github.com/wasmerio/wasmer).
## License
Mozilla Public License, v. 2.0, see LICENSE
Copyright 2016 CensoredUsername
## Guaranteed to be working compiler versions
This project used to be a compiler plugin, so for old compilers, here's a list of which version of dynasm was guaranteed to work with which compiler.
As the project has since transitioned to be a proc macro, this is not relevant for modern versions of the compiler.
- `v0.2.0`: `rustc 1.27.0-nightly (ac3c2288f 2018-04-18)`
- `v0.2.1`: `rustc 1.28.0-nightly (a1d4a9503 2018-05-20)`
- `v0.2.3`: `rustc 1.31.0-nightly (96cafc53c 2018-10-09)`