Hey Steve,

Looks like the NEC and M100 math routines are a fair amount different.

I have started a task of annotating the NEC VirtualT disassembly listing with the hand-coded changes I made to the M100 disassembly. We'll see how far I get along this path (There are a LOT of additions I made by hand).

Ken

On 2/18/23 12:07 PM, Stephen Adolph wrote:
Reviving this thread.

SuperROM uses RST1 to make "trampoline" calls to the main ROM.
I've gone through all of the RST1 calls that SuperROM makes to the M100 main rom.
Most convert well.

The really big gap is that the math routines are very different in PC-8201.

If there is anyone motivated to help, It would be helpful to figure out the equivalent calls PC-8201 calls for this list of M100 main ROM calls.

0x30C2
0x31B5
0x31B8
0x31BB
0x31C1
0x31C4
0x31CA
0x31CD
0x3469
0x3472
0x34D2
0x3501
0x3510
0x3513
0x35BA
0x35CF

Ideally requiring no major code rework on SuperROM to make it all work.





On Mon, Jul 12, 2021 at 8:30 AM Stephen Adolph <twospru...@gmail.com> wrote:

    Noting that SuperROM has never been found (or never released?) for
    NEC, it seems to me given what I know about making applications
    run on both platforms, that it should be very straightforward to
    translate the M100 SuperROM into an NEC variant.  After all, the
    NEC and M100 are so similar.

    Does anyone have any thoughts on this?

    Process could be:
    - Disassemble
    - find the trampoline, and adjust for NEC memory map
    - look for "trampoline" calls to the main ROM, and convert to NEC
    addresses
    - look for upper RAM addresses, and convert to NEC addresses
    ---> this could be a bit tricky I admit, because it may not always
    be apparent that a register pair value is being used as an upper
    RAM pointer
    - adjust the hardware interrupt  if needed


    cheers
    Steve



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