Am 06.12.25 um 18:06 schrieb Hill, Krista:
> Hello folks,
>
> I'm looking about for support for the 6801 micro, which has some useful
> features over the MC6800. In particular the A and B accumulators to form
> the 16 bit D register. I see that there is support for the 68HC08 and
> S08 which are related.
>
> Please, I'd like to know if there is or ever was any  interest in the
> 6801 micro. Also, a vague outline of what it would take to get the SDCC
> to provide such support, would be appreciated.
>
> Thanks in advance,
> Krista

I'm also interested in SDCC support for MC6800. I've developed MC6800
ports for several C compilers:

- chibicc-6800-v1 (https://github.com/zu2/chibicc-6800-v1)
- ack-6800 (https://github.com/zu2/ack-6800)

The as6800 assembler from https://shop-pdp.net/ashtml/ seems adaptable
to sdas/as6800 with minor fixes, but the work is still in progress.

Since MC6800 lacks ABX/XGDX/PSHX/PULX (which MC6801 has), X register
tracking becomes very important. It also lacks SUBD, so 2-byte
compare/branch sequences need multiple branch instructions, which adds
overhead—but that is exactly what makes it rewarding. For the backend,

I plan to first look at other processor backends to decide which one
to take as a reference. MCS51 is my first candidate; would you
recommend any other SDCC backend as a better starting point?

-- 
zu2


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