diff --git a/kernel/core.asm b/kernel/core.asm
index f23475a..b7a4af9 100644
--- a/kernel/core.asm
+++ b/kernel/core.asm
@@ -52,29 +52,24 @@ intoIX:
 	pop 	ix
 	ret
 
-; add the value of A into HL
+; add the value of A into HL, affecting flags like an ordinary addition
 addHL:
-	push	af
-	add	a, l
-	jr	nc, .end	; no carry? skip inc
-	inc	h
-.end:
-	ld	l, a
-	pop	af
+	push	de
+	ld 	d, 0
+	ld	e, a
+	add	hl, de
+	pop	de
 	ret
 
-; subtract the value of A from HL
+
+; subtract the value of A from HL, affecting flags like an ordinary subtraction
 subHL:
-	push	af
-	; To avoid having to swap L and A, we sub "backwards", that is, we add
-	; a NEGated value. This means that the carry flag is inverted
-	neg
-	add	a, l
-	jr	c, .end		; if carry, no carry. :)
-	dec	h
-.end:
-	ld	l, a
-	pop	af
+	push	de
+	ld	d, 0
+	ld	e, a
+	or 	a		;reset carry flag
+	sbc	hl, de		;There is no 'sub hl, de', so we must use sbc
+	pop	de
 	ret
 
 ; Compare HL with DE and sets Z and C in the same way as a regular cp X where