DOS_BOOT
Boot from disk
Categories:
| Function | Address | Description |
|---|---|---|
| DOS_BOOT | 012A | Boot from disk |
Synopsys
Boot from Disk
This routine loads a single bootstrap sector from the disk in drive A: into memory and enters it. This is for loading games or other operating systems.
Entry Parameters
None
Exit Parameters
- If OK:
- No exit as the bootstrap has taken over
- Otherwise:
- Carry false
- A=Error code
- Always:
- BC DE HL IX corrupt, all other registers preserved.
Bootstrap environment
When the bootstrap runs with the following memory configuration:
The bootstrap sector is on side 0, track 0, sector 1 of the disk. It is loaded into memory at 0xFE00 and entered at 0xFE10. Interrupts are disabled, and SP = 0xFE00.
The sum of all bytes in the sector must equal 3 MOD 256. Byte 15 in the sector can be used to adjust the sum to achive this. Bytes 0…15 of the sector hold the disk specification.
| Memory Range | RAM Bank | |
|---|---|---|
| 0x0000 | 0x3FFF | Bank 4 |
| 0x4000 | 0x7FFF | Bank 7 |
| 0x8000 | 0xBFFF | Bank 6 |
| 0xC000 | 0xFFFF | Bank 3 |
Last modified November 24, 2021: Start of +3DOS documentation (253d8cc)