Add beep when escape is sent

messages.asm

@@ -37,6 +37,8 @@ int 0x10
         je .newline
         cmp al, 0x08 ; delete character
         je .change_color_mode
+        cmp al, 0x1b ; escape character
+        je .beep
         jmp .nonewline
 
 .change_color_mode:
@@ -80,6 +82,32 @@ int 0x10
 
         jmp .loop
 
+.beep:
+        mov     al, 182         ; Prepare the speaker for the
+        out     43h, al         ;  note.
+        mov     ax, 4560        ; Frequency number (in decimal)
+                                ;  for middle C.
+        out     42h, al         ; Output low byte.
+        mov     al, ah          ; Output high byte.
+        out     42h, al
+        in      al, 61h         ; Turn on note (get value from
+                                ;  port 61h).
+        or      al, 00000011b   ; Set bits 1 and 0.
+        out     61h, al         ; Send new value.
+        mov     bx, 5000          ; Pause for duration of note.
+.pause1:
+        mov     cx, 65535
+.pause2:
+        dec     cx
+        jne     .pause2
+        dec     bx
+        jne     .pause1
+        in      al, 61h         ; Turn off note (get value from
+                                ;  port 61h).
+        and     al, 11111100b   ; Reset bits 1 and 0.
+        out     61h, al         ; Send new value.
+        jmp .loop
+
 
 .nonewline: