Renamed .error, removed trailing whitespace, more verbose comments.

apps/lib/parse.asm

@@ -26,17 +26,19 @@ parseDecimal:
 	ld	h, 0
 	ld	l, a	; load first digit in without multiplying
 	ld	b, 3	; Carries can only occur for decimals >=5 in length
-	jr	c, .error
+	jr	c, .end
 
 .loop:
 	exx
 	inc hl
 	ld a, (hl)
 	exx
-
+	
+	; inline parseDecimalDigit
 	add	a, 0xff-'9'	; maps '0'-'9' onto 0xf6-0xff
 	sub	0xff-9		; maps to 0-9 and carries if not a digit
-	jr	c, .error
+	
+	jr	c, .end
 	
 	add	hl, hl	; x2
 	ld	d, h
@@ -47,13 +49,13 @@ parseDecimal:
 	ld	d, 0
 	ld	e, a
 	add	hl, de
-	jr	c, .error	; if hl was 0x1999, it may carry here
+	jr	c, .end	; if hl was 0x1999, it may carry here
 	djnz	.loop
 
 
 	inc 	b	; so loop only executes once more
 	; only numbers >0x1999 can carry when multiplied by 10.
-	ld	de, 0xE666	
+	ld	de, 0xE666
 	ex	de, hl
 	add	hl, de
 	ex	de, hl
@@ -64,11 +66,12 @@ parseDecimal:
 	ld 	a, (hl)
 	exx
 	add 	a, 0xd0	; the next line expects a null to be mapped to 0xd0
-.error:
+.end:
+	; Because of the add and sub in parseDecimalDigit, null is mapped
+	; to 0x00+(0xff-'9')-(0xff-9)=-0x30=0xd0
 	sub 	0xd0	; if a is null, set Z
 			; a is checked for null before any errors
-.end:
 	push	hl \ pop ix
 	exx	; restore original de and bc
-	pop	hl	
+	pop	hl
 	ret