small cleanup in BASIC

c64/basic/engine/fetch_file_name.s

@@ -0,0 +1,58 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Fetches file name, Carry set if not found
+//
+
+
+fetch_filename:
+
+	// Check if end of statement
+
+	jsr end_of_statement_check
+	bcs fetch_filename_rts
+
+	// Search for opening quote
+
+	jsr basic_fetch_and_consume_character
+	cmp #$22
+	bne_16 do_SYNTAX_error
+
+	// Filename starts here so set pointer
+
+	lda TXTPTR+0
+	sta FNADDR+0
+	lda TXTPTR+1
+	sta FNADDR+1
+
+	// Now search for end of line or closing quote
+	// so that we know the length of the filename
+
+	lda #$00
+	sta FNLEN
+!:
+	jsr basic_fetch_and_consume_character
+	cmp #$22
+	beq fetch_filename_done
+	cmp #$00
+	beq !+
+
+	inc FNLEN
+	bne !-
+
+!:
+	jsr basic_unconsume_character
+
+	// FALLTROUGH
+
+fetch_filename_done:
+
+	clc
+
+	// FALLTROUGH
+
+fetch_filename_rts:
+
+	rts