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Last modified on 20 May 2018, at 05:12

DkTronics CPM

Revision as of 05:12, 20 May 2018 by Arnoldemu (Talk | contribs) (→‎NEWCPM.COM)

CPM+

CP/M+ already supports the Dk'Tronics RAM expansion but the CP/M+ on the system discs doesn't run on the CPC464/664 because it uses firmware v1.1 calls. Dk'Tronics provide patches to allow it to run on the 464/664.

CPM2.2

Creating the DkTronics 61K TPA CPM 2.2

Boot into CPM2.2 from system discs: 

A>disckit2

Use disckit2 to format a vendor disc. This will become 'Dk'Tonics CPM Disk'. 

A>BOOTGEN

This initialises the boot sector.

Source is: CPM 2.2 disk. Now insert 'Dk'tronics CPM Disk'. 


A>SYSGEN

This puts CPM2.2 onto the disc. Source is CPM2.2 disk. Destination is 'Dk'Tronics CPM Disk'. 


A>FILECOPY movcpm.com

This puts movcpm.com onto the disk. Source is 'CPM 2.2 system disc' disk. Destination is 'Dk'Tronics CPM Disk' disk. 

A>FILECOPY save.com

This puts save.com onto the disk. Source is 'CPM 2.2 system disc' disk. Destination is 'Dk'Tronics CPM Disk' disk. 

A>FILECOPY newcpm.com

This transfers Dk'Tronics newcpm.com. Source is 'Dk'Tronics bank switch software' disk. Destination is 'Dk'Tronics CPM Disk' disk. 


A>FILECOPY oldcpm.com

This transfers Dk'Tronics oldcpm.com. Source is 'Dk'Tronics bank switch software' disk. Destination is 'Dk'Tronics CPM Disk' disk.

Now boot the Dk'Tronics CPM Disk. 

A>MOVCPM 255 *

This configures a 63K CPM. 

A>SAVE 34 NEWCPM.SYS

This saves a 63K CPM for Dk'Tronics CPM to use.

Your Dk'Tronics CPM is setup.

Technical

  • 61K TPA is not active until NEWCPM.COM is run.
  • 61K CPM is stored in "NEWCPM.SYS" and is loaded by NEWCPM.COM

NEWCPM.COM

  • NEWCPM.COM is a normal COM file. It is loaded like a normal COM file. It resides in memory in bank 0 but configures a 61K CPM in bank 1 and transfers control to it. It remains in bank 0 and implements parts of the 61K CPM BIOS.
  • NEWCPM.COM sets up a BIOS jumpblock in page C7 at &FC00. This calls into the resident NEWCPM.COM code in bank 0
  • NEWCPM.SYS is first loaded to B00 in bank 0, it is later copied into bank 1 to it's correct location.

TPA upper address is &F300. BIOS jump is at &FC00. Code after &FC00 is part of the BIOS in bank 1.

OLDCPM.COM

  • OLDCPM.COM is much simpler than NEWCPM.COM. It restores the dormant CPM in bank 0. If NEWCPM.COM was used it remains dormant in bank 1.

Downloads