further IO stack refactoring

2019-10-29 17:03:13 +01:00
1 parent 6fa2c5b570
commit e9140607bc
@@ -0,0 +1,25 @@
+
+//
+// Official Kernal routine, described in:
+//
+// - [RG64] C64 Programmer's Reference Guide   - page 287/288
+// - [CM64] Compute's Mapping the Commodore 64 - page 240
+//
+// CPU registers that has to be preserved (see [RG64]): .A
+//
+
+MEMBOT:
+
+	bcc membot_set
+	
+	ldy MEMSTR+1
+	ldx MEMSTR+0
+
+	// FALLTROUGH
+
+membot_set:
+
+	sty MEMSTR+1
+	stx MEMSTR+0
+	
+	rts