Implemented bare-bones putchar() and puts()

src/x86/putc.c

@@ -1,11 +1,65 @@
 #include "stdio.h"
+#include <stddef.h>
+
+enum vga_color_t {
+	VGA_COLOR_BLACK = 0,
+	VGA_COLOR_BLUE = 1,
+	VGA_COLOR_GREEN = 2,
+	VGA_COLOR_CYAN = 3,
+	VGA_COLOR_RED = 4,
+	VGA_COLOR_MAGENTA = 5,
+	VGA_COLOR_BROWN = 6,
+	VGA_COLOR_LIGHT_GREY = 7,
+	VGA_COLOR_DARK_GREY = 8,
+	VGA_COLOR_LIGHT_BLUE = 9,
+	VGA_COLOR_LIGHT_GREEN = 10,
+	VGA_COLOR_LIGHT_CYAN = 11,
+	VGA_COLOR_LIGHT_RED = 12,
+	VGA_COLOR_LIGHT_MAGENTA = 13,
+	VGA_COLOR_LIGHT_BROWN = 14,
+	VGA_COLOR_WHITE = 15,
+};
+
+__attribute__ ((packed))
+struct cell_t
+{
+    char c;
+    char fg : 4;
+    char bg : 4;
+};
+
+struct cell_t *screen = 0xFFCB8000;
+
+const size_t tab_width = 4;
+const size_t line_width = 80;
 
 int putchar(int c)
 {
-
+    switch(c)
+    {
+    case '\n':
+        screen += line_width;
+        screen -= (size_t) screen % line_width;
+        break;
+    case '\t':
+        screen += (tab_width) & ~(tab_width);
+        break;
+    case '\r':
+        screen -= line_width - 1;
+        screen += line_width - ((size_t) screen % line_width);
+        break;
+    default:
+        screen->c = (char) c;
+        screen++;
+    }
+    return c;
 }
 
 int puts(const char *str)
 {
-    
+    while(*str)
+    {
+        putchar(*str);
+    }
+    return 0;
 }