//! UART low-level driver.
//!
//! Minimal polling driver used by the kernel for early console output.
const UART_BASE: *mut u8 = 0x10000000 as *mut _;
/// Write a single character to the UART using a simple polling loop.
///
/// This is a very small, platform-specific driver used for early boot
/// console output; it busy-waits until the UART indicates it can accept
/// a new byte.
pub fn write_char_uart(c: char) {
    while unsafe { (core::ptr::read_volatile(UART_BASE.byte_add(0x5)) >> 5) & 1 == 0 } {}
    unsafe { core::ptr::write_volatile(UART_BASE, c as u8) };
}

/// Write a UTF-8 string to the UART.
///
/// Automatically injects a carriage-return after newline to support terminals
/// that expect CRLF pairs.
pub fn write_uart<T: AsRef<str>>(print: T) {
    for a in print.as_ref().chars() {
        // Add \r if needed
        write_char_uart(a);
        if a == '\n' {
            write_char_uart('\r');
        }
    }
}