correct memory_model comment, fix serial _print

blog/intro.org

@@ -653,7 +653,7 @@ The same is true also for the =Request= type, except that we have to bound the i
  Relevant to us are the =addr= field, and the fields describing how the (sub)pixels =addr= points to are laid out in memory.
  =width= and =height= describe the dimensions of the framebuffer in pixels, =pitch= describes how many bytes are used for each row of pixels, and =bpp= describes how many bits are used for each pixel.
  =bpp= can be assumed to be a multiple of 8. We will additionally assume that =bpp= is always at most 64.
- =memory_model= is the [[https://www.ctyme.com/intr/rb-0274.htm#Table82][VESA SVGA memory model]] the framebuffer uses, and at least at the time of writing, the only value reported by limine is =6=.
+ =memory_model= is currently always =1=, meaning =LIMINE_FRAMEBUFFER_RGB=, but might in the future allow for other memory models in order to support [[https://www.ctyme.com/intr/rb-0274.htm#Table82][VESA SVGA memory model]] values other than Direct Color.
  The =mask_size= and =mask_shift= fields describe how the respective color channels are to be organised with a =bpp / 8= byte memory region.
 
  To draw an rgb-colored pixel at a given position =(x, y)= then, we will define the following function:

kernel/src/serial.rs

@@ -755,7 +755,9 @@ pub mod uart_16550 {
                                 // terminal
                                 self.uart.send_bytes_exact(&[8, b' ', 8]);
                             }
-                            _ => {}
+                            _ => {
+                                self.uart.send_bytes_exact(&[*special]);
+                            }
                         }
                     }
                 });
@@ -771,7 +773,7 @@ pub mod uart_16550 {
 }
 
 #[doc(hidden)]
-pub fn _print(args: core::fmt::Arguments) {
+pub fn _print(args: core::fmt::Arguments, nl: bool) {
     #[cfg(target_arch = "x86_64")]
     {
         use core::fmt::Write;
@@ -784,14 +786,18 @@ pub fn _print(args: core::fmt::Arguments) {
             }
         }
 
-        Writer(&uart_16550::SERIAL1).write_fmt(args).unwrap();
+        let mut writer = Writer(&uart_16550::SERIAL1);
+        writer.write_fmt(args).unwrap();
+        if nl {
+            writer.write_str("\n").unwrap();
+        }
     }
 }
 
 #[macro_export]
 macro_rules! serial_print {
     ($($arg:tt)*) => {
-        $crate::serial::_print(format_args!($($arg)*));
+        $crate::serial::_print(format_args!($($arg)*), false);
     };
 }
 
@@ -800,12 +806,7 @@ macro_rules! serial_println {
     () => {
         $crate::serial_print!("\n");
     };
-    ($fmt:expr) => {
-        $crate::serial_print!(concat!($fmt, "\n"));
-    };
-    ($fmt:expr, $($arg:tt)*) => {
-        $crate::serial_print!(
-            concat!($fmt, "\n"), $($arg)*
-        );
+    ($($arg:tt)*) => {
+        $crate::serial::_print(format_args!($($arg)*), true);
     };
 }