| Function | Address | Description |
|---|---|---|
| DD_ENCODE | 0184 | Set copy protection encode routine |
Synopsys
Set the copy protection ENCODE subroutine.
Copy protected disks have some of their track and sector numbers encoded on disk. Before each disk access, the ENCODE subroutine is called to encode the physical track and sector numbers.
These encoded track and sector numbers must match those in the sector identifier.
Note that tracks 0…2 on either side of a disk should not be encoded.
Entry Parameters
| Register | Content |
|---|---|
| A | Enable 0xFF or disable 0x00 |
| HL | If enabled address of ENCODE routine |
Exit Parameters
- HL = Address of previous encode routine, 0 if none
- Always:
- AF BC DE IX corrupt, all other registers preserved.
ENCODE routine
If you are substituting your own ENCODE subroutine, the 'entry conditions' are the conditions passed to your subroutine, and the 'exit conditions' are the values that your subroutine must produce and the registers you are allowed to corrupt.
Entry Parameters
| Register | Content |
|---|---|
| C |
Unit/Side Bits 0…1 = unit, Bit 2 = side |
| D | Physical track |
| E | Physical sector |
| IX | Address of DPB |
Exit Parameters
- D = Encoded physical track
- E = Encoded physical sector
- Always:
- AF corrupt, all other registers preserved.