Create basic MCB at boot

boot/kernel.asm

@@ -3,6 +3,7 @@
 	jmp 0x07C0:init
 
 	%include "inc/bpb.asm"
+	%include "kernel/mcb.asm"
 
 banner:	db "rdos", 0xA, 0xD, 0
 
@@ -39,8 +40,6 @@ entry:	push bp
 	mov ss, ax
 	xor sp, sp
 
-	int 3
-
 	; Jump back to userspace
 ujump:	cli
 	mov ax, es
@@ -233,9 +232,8 @@ init:	cli
 
 	call dnconv
 	call select
-	int 3
-	mov ax, [cs:bpb+bpb_ss]
-	int 3
+
+	call mcb_init
 
 main:	push cs
 	pop ds