Changes

CP/M 2.2

900 bytes added, 18:31, 5 May 2018
/* Technical information */
4. Finally the boot code calls CPM "WBOOT".
* WBOOT loads multiple sectors 1 sector from track 0, sector 48 to the reserved trackssector buffer. This is the first sector of platform independent part of CPM. * It then peeks into the buffer reading and reads from offset 1, 2 the address of the first JP of the CPM code. This is normally JP &9A5C.  * It adds &FCA4 to this address to get the start loading address for CPM CCP/BIOS which becomes &9700. Then it copies the sector into RAM. Therefore this address is used to relocate CCP/BIOS. * It now loads 10 furthur sectors (of the platform independent CPM system ) to start + &200 (normally &9900). This goes up to &AD00. * It adds &EA00 to &AD00 to get back the original start of &9700. It remembers this. * It adds &F206 to start (&9700) to get the start of the BDOS etc(normally &9F06) and stores this address in the JP at &0005. * It recalculates the BDOS jumpblock (normally at &AD00 and stores the address of the WBOOT) * Next it copies the bios jumpblock from the ROM to this address. * Finally it jumps into CCP and starts it (&9700).
=== Memory Map ===
2,541
edits