diff --git a/kernel/core.asm b/kernel/core.asm
index f23475a..643c832 100644
--- a/kernel/core.asm
+++ b/kernel/core.asm
@@ -126,14 +126,16 @@ callIY:
 	jp	(iy)
 
 ; Ensures that Z is unset (more complicated than it sounds...)
+; There are often better inline alternatives, either replacing rets with 
+; appropriate jmps, or if an 8 bit register is known to not be 0, an inc 
+; then a dec. If a is nonzero, 'or a' is optimal.
 unsetZ:
-	push	bc
-	ld	b, a
-	inc	b
-	cp	b
-	pop	bc
+	or 	a	;if a nonzero, Z reset
+	ret	nz
+	cp 	1	;if a is zero, Z reset
 	ret
 
+
 ; *** STRINGS ***
 
 ; Fill B bytes at (HL) with A
@@ -179,15 +181,19 @@ findchar:
 	pop	bc
 	ret
 
+
 ; Format the lower nibble of A into a hex char and stores the result in A.
+; daa does the following operation if we were working in a high level language:
+; a += (2*N-1)*(0x60*(a >= 0xa0) + 0x06*((a & 0x0f) >= 0x0a)) 
+; N is the Negative flag. The C and H flags are also taken into account, but we
+; clear both so this is a good enough description for our purposes.
 fmtHex:
-	and	0xf
-	cp	10
-	jr	nc, .alpha	; if >= 10, we have alpha
-	add	a, '0'
-	ret
-.alpha:
-	add	a, 'A'-10
+	; we need to make the upper nibble a known value
+	; also clears the N, C and H flags for daa
+	or 0xf0	
+	daa	; now a =0x50 + the original value + 0x06 if >= 0xfa
+	add a, 0xa0	; cause a carry for the values that were >=0x0a
+	adc a, 0x40
 	ret
 
 ; Formats value in A into a string hex pair. Stores it in the memory location
@@ -204,7 +210,6 @@ fmtHexPair:
 	dec	hl
 	pop	af
 	push	af
-	and	0xf0
 	rra \ rra \ rra \ rra
 	call	fmtHex
 	ld	(hl), a
@@ -212,6 +217,7 @@ fmtHexPair:
 	pop	af
 	ret
 
+
 ; Compares strings pointed to by HL and DE up to A count of characters. If
 ; equal, Z is set. If not equal, Z is reset.
 strncmp:
diff --git a/kernel/parse.asm b/kernel/parse.asm
index 1bd81b2..9c97992 100644
--- a/kernel/parse.asm
+++ b/kernel/parse.asm
@@ -11,26 +11,21 @@
 ; On success, the carry flag is reset. On error, it is set.
 parseHex:
 	; First, let's see if we have an easy 0-9 case
-	cp	'0'
-	jr	c, .error	; if < '0', we have a problem
-	cp	'9'+1
-	jr	nc, .alpha	; if >= '9'+1, we might have alpha
-	; We are in the 0-9 range
-	sub	'0'		; C is clear
-	ret
+	sub	'0'
+	ret	c
+	cp	10
+	ccf
+	ret	nc
 
 .alpha:
-	call	upcase
-	cp	'A'
-	jr	c, .error	; if < 'A', we have a problem
-	cp	'F'+1
-	jr	nc, .error	; if >= 'F', we have a problem
+	and 	0xdf		; converts uppercase to lowercase
+	sub	0x11		; C if <'A'
+	ret	c
+	cp	6		; not C if >'F'
+	ccf
+	ret	c
 	; We have alpha.
-	sub	'A'-10		; C is clear
-	ret
-
-.error:
-	scf
+	add	a, 10		; C is clear
 	ret
 
 ; Parses 2 characters of the string pointed to by HL and returns the numerical