Refactor

src/uart.rs

@@ -1,15 +1,27 @@
+//! 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 {}
+    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) {
-    print.as_ref().chars().for_each(|a| {
+    for a in print.as_ref().chars() {
         // Add \r if needed
         write_char_uart(a);
         if a == '\n' {
             write_char_uart('\r');
         }
-    });
+    }
 }