//! By convention, main.zig is where your main function lives in the case that
//! you are building an executable. If you are making a library, the convention
//! is to delete this file and start with root.zig instead.
//const std = @import("std");

const gpio = packed struct {
    moder: u32,
    otyper: u32,
    ospeedr: u32,
    pupdr: u32,
    idr: u32,
    odr: u32,
    bsrr: u32,
    lckr: u32,
    afrl: u32,
    afrh: u32,
    brr: u32,
    ascr: u32,
};

const cpu = struct {
    pub fn interrupt_disable() void {
        asm volatile("cpsid i");
    }

    pub fn interrupt_enable() void {
        asm volatile("cpsie i");
    }
};

const gpioa: *gpio = @ptrFromInt(0x48000000);
const rcc: *[39]u32 = @ptrFromInt(0x40021000);

export fn _start() callconv(.C) noreturn {
    cpu.interrupt_disable();

    rcc[19] |= 1; // gpioaen
    gpioa.moder &= ~@as(u32, 0x3 << (5 * 2));
    gpioa.moder |= (1 << (5 * 2));

    while (true) {
        gpioa.odr ^= (1 << 5);
    }
}

export fn fault_handler() callconv(.C) void {
    while (true) {}
}