small cleanup in BASIC

c64/basic/engine/fetch_device_secondary.s

@@ -0,0 +1,44 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Fetches device number and secondary address - if they are present
+//
+
+
+fetch_device_secondary:
+
+	// Fetch the device number
+
+	jsr injest_comma
+	bcs fetch_secondary
+
+	jsr basic_parse_line_number
+	lda LINNUM+1
+	bne_16 do_ILLEGAL_QUANTITY_error
+
+	lda LINNUM+0
+	sta FA
+
+	// FALLTROUGH
+
+fetch_secondary:
+
+	// Fetch secondary address
+
+	jsr injest_comma
+	bcs fetch_device_secondary_done
+
+	jsr basic_parse_line_number
+	lda LINNUM+1
+	bne_16 do_ILLEGAL_QUANTITY_error
+
+	lda LINNUM+0
+	sta SA
+
+	// FALLTROUGH
+
+fetch_device_secondary_done:
+
+	rts