Microtan technical reference
System variables
TANBUG monitor variables and reserved zero-page locations.
| Address | Use |
|---|---|
0000 | Used by breakpoints |
0001 | Last ASCII-keyboard character |
0002 | Temporary character store |
0003 | Display index |
0004–0006 | Fast interrupt link |
0007–0009 | NMI link |
000A–000B | Cursor index |
000C | Zero if in a user program |
000D | Non-zero if in single-instruction mode |
000E | Proceed counter |
000F | Hexadecimal or ASCII keyboard |
0010–0012 | Slow interrupt link |
0013–0014 | Used by the HEXPACK routine |
0015–0016 | Pseudo program counter |
0017 | Pseudo processor status word |
0018 | Pseudo stack pointer |
0019 | Pseudo X index |
001A | Pseudo Y index |
001B | Pseudo accumulator |
001C–001D | Temporary store |
001E–001F | Copy store |
0020–002F | Breakpoint addresses |
0030–003F | Breakpoint code store |