Rom map:
+----------+ 0000
| BIOS     |
+----------+ 0400
| BASIC    |
+----------+ 2400

Bios copies itself and basic to the top 16k which then look like:
+----------+ c000
| INT VEC  |
+----------+ c050
| BIOS API |
+----------+
| BIOS     |
+----------+ c400
| BIOS VAR |
+----------+ c800
| BASIC    |
+----------+ e800
| BASIC WS |
|   ....   |
| BASIC ST |
+----------+ ffff