Thanks Ken,

I do have an example.

1. Put a breakpoint at 6F58
2. Go to TELCOM and type TERM
3. Look at the Instruction Trace. It will say 6F58s MVI A, 03H

4. Go to the ROM source listing.
You will notice there is no command at 6F58H. Instead it says 
; ======================================================
; Initialize RS232 or modem
; ======================================================
6F52H  (3EH) MVI A,01H
6F54H  (01H) LXI B,023EH
6F57H  (01H) LXI B,033EH
6F5AH  (E5H) PUSH H

To me it looks like the debugger got off track at the bottom of the ROM.

Kurt


On Fri, Apr 10, 2026, at 3:06 PM, Kenneth Pettit wrote:
> Hi Kurt,
> 
> Umm, I believe the disassembler *should* be looking at the ROM if I remember 
> correctly.  Could just be a latent bug.  Do you have examples of 
> discrepancies?
> 
> Ken
> On 4/10/26 12:35 PM, Kurt McCullum wrote:
>> I am running into a problem with the disassembler for the main ROM in 
>> Virtual-T for the NEC 8201a.
>> 
>> In particular, the RS232 initialize routines don't match what the ROM and 
>> debugger show as far as code.
>> 
>> For the main ROM, is the disassembler actually looking at the ROM, or 
>> something else?
>> 
>> Kurt

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