View Full Version : Jumping to program in TPA?

January 8th, 2011, 10:21 AM

I'm in the process of bringing up CP/M on my CCS 2422 FDC / 2810 CPU combo. So far, I've hacked up my monitor to correctly receive and transmit Intel hex (to/from RAM) over serial. I'm able to load RAM with CCBIOS (for these cards) and CPM 2.2 image (BDOS + CCP). When trying to enter CP/M from warm boot vector, I get "CPM 61K" then "Drive Select Error"

My problem is my 8" disks are not formatted, so I think all the sector seek read low level ops are failing in BIOS and the Monitor. The disks need to be formatted on a per track basis. Saving myself from developing the format code, I'm trying to use one of CCS's programs that does that job. It's called CCSINIT.COM.

I then load CCSINIT.COM (as hex with correct offset) into 0x0100 (TPA). I jump to it from the Monitor however it's exiting out.

Does anyone know of tricks to get TPA to run even if CCP/BDOS initialization routines haven't completely run? Anyone with code snipits for WD 179X formatting routines?


January 8th, 2011, 10:47 AM
Have you set up CDISK (location 0004) correctly in your BIOS initialization? Leaving garbage in that cell will lead to grief.

There's no reason that a program can't be made to run without an initialized BIOS as long as the program makes no BDOS or BIOS calls. I strongly suspect that CCSINIT does make such calls.

January 10th, 2011, 04:48 AM
Hi atod,

If the program calls to BDOS (or BIOS), You'll have problems (for example, writting to the screen the copyright or title).

One posibility is to do changes in CBIOS to support a ram drive and load there your format utility.

In that case, the book THE CP/M HANDBOOK by A. J. LAIRD can help you.

Good luck!