p256-cortex-m4-sys 0.1.0-alpha.2

use std::env;
use std::path::PathBuf;

fn main() -> Result<(), Box<dyn std::error::Error>> {

    println!("cargo:rerun-if-changed=build.rs");
    println!("cargo:rerun-if-changed=P256-Cortex-M4/p256-cortex-m4.h");
    println!("cargo:rerun-if-changed=P256-Cortex-M4/p256-cortex-m4.c");
    println!("cargo:rerun-if-changed=p256-cortex-m4-range-checks.h");

    let target = env::var("TARGET")?;

    // Cortex-M33 is compatible with Cortex-M4 and its DSP extension instruction UMAAL.
    let cortex_m4 = target.starts_with("thumbv7em") || target.starts_with("thumbv8m.main");

    if cortex_m4 {
        println!("cargo:rustc-cfg=cortex_m4");
        let mut builder = cc::Build::new();

        let builder = builder
            .flag("-std=c11")
            .file("P256-Cortex-M4/p256-cortex-m4.c")
            .file("P256-Cortex-M4/p256-cortex-m4-asm-gcc.S")
            .flag("-march=armv7e-m")
        ;

        builder.compile("micro-ecc-sys");

        let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());

        let bindings = bindgen::Builder::default()
            .header("P256-Cortex-M4/p256-cortex-m4.h")
            .header("p256-cortex-m4-range-checks.h")
            .clang_arg(format!("--target={}", target))
            .use_core()
            .ctypes_prefix("cty")
            .rustfmt_bindings(true)

            .generate()
            .expect("Unable to generate bindings");

        let out_file = out_dir.join("bindings.rs");

        bindings
            .write_to_file(out_file)
            .expect("Couldn't write bindings!");
    }

    Ok(())
}