diff --git a/apps/ed/cmd.asm b/apps/ed/cmd.asm
index 618b3dd..2a90494 100644
--- a/apps/ed/cmd.asm
+++ b/apps/ed/cmd.asm
@@ -89,8 +89,11 @@ cmdParse:
 	jr	z, .dot
 	cp	'$'
 	jr	z, .eof
-	add 	a, 0xc6	; inline parseDecimalDigit
-	sub 	0xf6
+	
+	; inline parseDecimalDigit
+	add 	a, 0xc6	; maps '0'-'9' onto 0xf6-0xff
+	sub 	0xf6	; maps to 0-9 and carries if not a digit
+	
 	jr	c, .notHandled
 	; straight number
 	ld	a, ABSOLUTE
@@ -122,8 +125,11 @@ cmdParse:
 	inc	hl		; advance cmd cursor
 	ld	a, (hl)
 	ld	de, 1		; if .pmNoSuffix
-	add 	a, 0xc6	; Inline parseDecimalDigit
-	sub 	0xf6
+	
+	; inline parseDecimalDigit
+	add 	a, 0xc6	; maps '0'-'9' onto 0xf6-0xff
+	sub 	0xf6	; maps to 0-9 and carries if not a digit
+	
 	jr	c, .pmNoSuffix
 	call	.parseDecimalM	; --> DE
 .pmNoSuffix:
@@ -151,8 +157,11 @@ cmdParse:
 .loop:
 	inc	hl
 	ld	a, (hl)
-	add 	a, 0xc6	; Inline parseDecimalDigit
-	sub 	0xf6
+	
+	; inline parseDecimalDigit
+	add 	a, 0xc6	; maps '0'-'9' onto 0xf6-0xff
+	sub 	0xf6	; maps to 0-9 and carries if not a digit
+	
 	jr	nc, .loop
 	; We're at the first non-digit char. Let's save it because we're going
 	; to temporarily replace it with a null.