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//! A module for working with MCU.

use core::ptr::write_volatile;

const AIRCR: usize = 0xE000_ED0C;

/// Wait for Interrupt.
pub fn wait_for_interrupt() {
  unsafe {
    asm!("wfi" :::: "volatile");
  }
}

/// Performs a system reset request.
///
/// This function writes to the application interrupt and reset control register
/// (`AIRCR`).
pub fn reset_request() {
  unsafe {
    write_volatile(AIRCR as *mut usize, 0x05FA_0004);
  }
}

/// Spins a specified amount of CPU cycles.
pub fn spin(mut _cycles: u32) {
  unsafe {
    asm!("
      0:
        subs $0, $0, #2
        bhi 0b
    " : "+r"(_cycles)
      :
      : "cc"
      : "volatile");
  }
}