os_metal_primitives

os_metal_primitives is a dependency-free, no_std-first crate that provides small, strongly typed building blocks for bare-metal / OS kernel development in Rust (edition 2024).

This crate focuses on low-level primitives you can reuse across kernels and architectures:

Typed MMIO registers with volatile reads/writes (mmio::MmioCell)
Bitfield helpers and a compact declarative macro (os_metal_primitives::bitfield!)
Register access modes (RO/WO/RW) and a register block helper macro (os_metal_primitives::define_register_block!)
Port I/O wrapper types (port_io::{Port8, Port16, Port32}) via an architecture-provided trait
IRQ types and a fixed-size, allocation-free dispatch table (irq::IrqTable)
Driver state helpers for explicit driver lifecycles (driver_state::DriverState)

Relationship with your other crates

This crate is intentionally independent and does not depend on:

os_kernel_foundry (kernel architecture & boot orchestration)
os_dev_toolkit (logging, diagnostics, fixed buffers, etc.)

Instead, it complements them by handling different concerns: typed hardware register access, bit manipulation primitives, and small kernel-friendly patterns.

Quick example: MMIO + bitfields

use os_metal_primitives::mmio::MmioCell;

os_metal_primitives::bitfield! {
    /// A tiny control register.
    pub struct Ctrl(u32) {
        /// Enable bit.
        pub const EN: 0,
        /// 3-bit mode field.
        pub field MODE: 8..=10,
    }
}

#[repr(C)]
pub struct DevRegs {
    pub ctrl: MmioCell<u32>,
}

fn enable_and_set_mode(regs: &DevRegs, mode: u32) {
    regs.ctrl.update(|raw| {
        let c = Ctrl::from_bits(raw)
            .with(Ctrl::EN)
            .set(Ctrl::MODE, mode);
        c.bits()
    });
}

Documentation

API docs: build locally with cargo doc --open
Project docs: see the docs/ directory, starting from docs/MANUAL.md

License

MIT. See LICENSE.

Attribution