Re: Disassembly of the Z80 ROM of the C128

From: smf <*smf_at_null.net*> Date: Wed, 1 Mar 2017 00:02:36 +0000 Message-ID: <db504e5c-01b1-2d32-fb66-2a9a01886c95@null.net> · smf_at_null.net

On 28/02/2017 15:06, geneb wrote:
>
> Patches that were done were applied to the BIOS, not the ROM. Keep in 
> mind that under CP/M, the BIOS is loaded off of disk and isn't 
> ROM-resident.  CP/M is kind of a stack.  The BDOS, the BIOS, and the 
> CCP. The BDOS is the same for every CP/M system.  The BIOS is modified 
> to match the hardware that CP/M is running on, and the CCP is 
> basically equivalent to COMMAND.COM in DOS - it's transient.

The phone call was about the boot ROM for the Z80, that worked out 
whether to go into C64 mode or C128 mode. Before that call the 6502 
started first & it tried to handle the mode switch, but that caused a 
problem with the magic voice cartridge.

It had nothing to do with CPM.

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