feature: add a few helpers fn (is...)

fix: print unprintable characters no longer occurs

src/kernel.c

@@ -29,5 +29,8 @@ void kernel_main(void)
 	init_idt();
 	init_memory();
 	load_drivers();
+	kprintf("I see no way to confuse an array of 256 seg:off pairs with a "
+	        "complex 8*unknown quantity -byte descriptor table. -- Troy "
+	        "Martin 03:50, 22 March 2009 (UTC)\n");
 	shell_init();
 }

src/shell/exec.c

@@ -2,7 +2,7 @@
 
 #include "alloc.h"
 #include "commands.h"
-#include "drivers.h"
+#include "ctype.h"
 #include "kprintf.h"
 #include "shell.h"
 #include "string.h"

src/terminal/get.c

@@ -20,7 +20,8 @@ struct key_event terminal_getkey(void)
 	         scan_code == KEY_LEFT_SHIFT + 128)
 		caps_mode = false;
 	if (scan_code < 128) {
-		ev.c = keymap[scan_code][caps_mode];
+		if (keymap[scan_code])
+			ev.c = keymap[scan_code][caps_mode];
 		if (scan_code >= KEY_F1 && scan_code <= KEY_F10)
 			terminal_set_screen(scan_code - KEY_F1);
 		ev.scan_code = scan_code;