Deduplicate code for byte savings

Saves a whole whopping 6 bytes!

Author: gamax92

roms/boot.s

@@ -474,30 +474,27 @@ fschk:
 	dec $03
 	bra @loop
 
-hex2val:
-	; Converts two hexadecimal characters to a value
-	lda $00,X
-	clc
-	sbc #$2f
-	cmp #$11
-	bcc :+
-	clc
-	sbc #$06
-:	sta good
-	dex
+_hex2val:
+	; Converts one hexadecimal characters to a value
 	lda $00,X
 	clc
 	sbc #$2f
 	cmp #$11
 	bcc :+
-	clc
-	sbc #$06
-:	asl
+	sbc #$07
+:	dex
+	rts
+
+hex2val:
+	; Converts two hexadecimal characters to a value
+	jsr _hex2val
+	sta good
+	jsr _hex2val
+	asl
 	asl
 	asl
 	asl
 	eor good
-	dex
 	sta (curlow),Y
 	iny
 	rts