#![no_std]
#![no_main]

extern crate panic_halt;

use core::{arch::asm, ptr::{write, read}};
use core::fmt::Write;

use embedded_hal::prelude::_embedded_hal_blocking_i2c_Write;
use riscv_rt::entry;

mod eth;
mod i2c;
mod uart;

// use `main` as the entry point of this application
// `main` is not allowed to return
#[entry]
fn main() -> ! {
    //unsafe { eth::init(); }

    //let blink_period = unsafe {
    //    if eth::is_wishbone_correct() {
    //        10_000_000
    //    } else {
    //        500_000
    //    }
    //};
    let blink_period = 10_000_000u32;

    //let mut i2c = i2c::AmlibI2c::new(0x0200_0000);
    //let data = [0u8, 2u8];
    //i2c.write(0xAA, &data).unwrap();

    let mut uart = uart::AmlibUart::new(0x0200_0040);

    loop {
        //eth::tranmsit();
        uart.write_str("Hello world!\r\n");
        write_led(0);
        busy_wait(blink_period);
        write_led(1);
        busy_wait(blink_period);
    }
}

fn busy_wait(num_nops: u32) {
    for _ in 0..num_nops {
        unsafe {
            asm!("nop");
        }
    }
}

fn write_led(val: u32) {
    unsafe { write_reg(0x01003000, val); }
}

unsafe fn write_reg<T>(addr: u32, value: T) {
    write(addr as *mut T, value);
}

unsafe fn read_reg<T>(addr: u32) -> T {
    return read(addr as *mut T);
}