variable support cleanup

src/basic/engine_runtime/prepare_direct_execution.s

@@ -0,0 +1,38 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# M65 BASIC_1 #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Prepare interpreter to execute commands in direct mode
+//
+
+prepare_direct_execution:
+
+#if (ROM_LAYOUT_M65 && SEGMENT_BASIC_0)
+
+	jsr     map_BASIC_1
+	jsr_ind VB1__prepare_direct_execution
+	jmp     map_NORMAL
+
+#else
+
+	// Setup pointer to the statement
+	lda #<BUF
+	sta TXTPTR+0
+	lda #>BUF
+	sta TXTPTR+1
+
+	// There is no stored line, so zero that pointer out
+	lda #$00
+	sta OLDTXT+0
+	sta OLDTXT+1
+
+	// Put invalid line number in current line number value,
+	// so that we know we are in direct mode (Computes Mapping the 64 p19)
+	lda #$FF
+	sta CURLIN+1
+
+	rts
+
+#endif // ROM layout