Add printstr functionality

rust_experiments/src/lib.rs

@@ -1,5 +1,5 @@
 
-#![feature(no_std, lang_items, const_fn, asm)]
+#![feature(no_std, lang_items, const_fn, asm, core_str_ext)]
 #![no_std]
 
 #[cfg(test)]
@@ -9,6 +9,8 @@ extern crate std;
 extern crate rlibc;
 extern crate multiboot2;
 
+use core::fmt::Write;
+
 /* externs */
 #[no_mangle]
 pub extern fn rust_setup_PIC() {
@@ -182,7 +184,9 @@ pub extern fn rust_main(multiboot_info_header: usize) {
     clear();
     checkerboard(Color::Red);
 
-    let boot_info = unsafe { multiboot2::load(multiboot_info_header) };
+    //let boot_info = unsafe { multiboot2::load(multiboot_info_header) };
+
+    printstr::write_to_screen(6, "hello you person: {}");
 
     loop {
 
@@ -231,6 +235,39 @@ mod util {
     }
 }
 
+mod printstr {
+    use vga_buffer::{Color, ColorCode, write_to_coord};
+
+    const std_code: ColorCode = ColorCode::new(Color::LightBlue, Color::Black);
+
+    pub fn write_to_screen(line_num: u8, s: &str) {
+
+        let mut x_position: usize = 0;
+        let mut y_position: usize = line_num as usize;
+
+        for ch in s.bytes() {
+
+            if x_position > ::vga_buffer::BUFFER_WIDTH {
+                x_position = 0;
+                y_position += 1;
+            }
+
+            if y_position > ::vga_buffer::BUFFER_HEIGHT {
+                return;
+            }
+
+            match ch {
+                b'\n' => { y_position += 1; x_position = 0; },
+                byte => {
+                    write_to_coord(x_position, y_position, byte, std_code);
+                    x_position += 1;
+                }
+            }
+        }
+    }
+
+}
+
 mod vga_buffer {
     #[repr(u8)]
     #[derive(Clone, Copy)]