use hcl::platform::scs;


static mut MILLIS : u32 = 0;

pub unsafe extern fn isr() {
    MILLIS = MILLIS.wrapping_add(1);
}

pub fn configure(st: &mut scs::Systick) {
    st.configure(|s| s
        .set_internally_clocked(true)
        .set_interrupt_enabled(true)
        .set_reload_value(40_000)
        .set_enabled(true));
}


pub fn millis() -> u32 {
    unsafe {
        return MILLIS;
    }
}

pub fn delay_ms(ms: u32) {
    let start = millis();
    while millis().wrapping_sub(start) < ms {
        unsafe { asm!("wfi" :::: "volatile"); }
    }
}