diff --git a/boot/kernel.asm b/boot/kernel.asm
index 60dda98..9741d4e 100644
--- a/boot/kernel.asm
+++ b/boot/kernel.asm
@@ -94,44 +94,31 @@ sftab:	dw sferr, sferr, sferr, sferr
 	dw sferr, sferr, sferr, sferr
 	dw sferr, sferr, sferr, sferr
 
-	; IN	al	number
-	; OUT	bx	al * 4
-times4:	push ax
-	xor ah, ah
-	add al, al
-	add al, al
-	mov bx, ax
-	pop ax
-	ret
-
 	; DOS 2+ - GET INTERRUPT VECTOR
 	; IN	al	interrupt number
 	; OUT	es:bx	current interrupt handler
-getint:	push ds
-	; DS=0
-	xor bx, bx
-	mov ds, bx
+getint:	xor bx, bx
 	; BX=AL*4
-	call times4
-	les bx, [bx]
-	pop ds
+	mov bl, al
+	add bl, bl
+	add bl, bl
+	; load vector into ES:BX
+	les bx, [cs:bx]
 	ret
 
 	; DOS 25h: Set interrupt vector
 	; IN	al	interrupt number
 	;	ds:dx	entry point
-setint:	push es
-	push bx
-	; ES=0
+setint:	push bx
 	xor bx, bx
-	mov es, bx
 	; BX=AL*4
-	call times4
-	mov [es:bx], dx
-	mov ax, ds
-	mov [es:bx+2], ds
+	mov bl, al
+	add bl, bl
+	add bl, bl
+	; save DS:DX into vector
+	mov [cs:bx], dx
+	mov [cs:bx+2], ds
 	pop bx
-	pop es
 	ret
 
 bpb:	times bpb_len db 0