Andy, I'm getting an addressing mode error when attempting to use LAX #imm in MADS. I'm using a lot of signed 16 bit arithmetic in the GUI, so this technique could be really useful. Of course I can set up a macro to get around the error problem.
I had modify ACME when I wanted to start using that instruction, well that addressing mode, and I guess only some assemblers support the immediate version, unless the author just carpet bombed the instruction set and implemented everything they could find.. I think up until fairly recently it was considered an off limits illegal instruction simply because it was so volatile, but now it's clear there's a few cases where it's stable and it's starting to get a bit more use, well I speak for myself there anyway..
The odd thing is that it doesn't turn up in many of the documents about illegals..
If you're feeling brave:
is good as well by all counts, though I've yet to convince myself that I trust it yet
That 16bit negate, can also do two 8 bit negates as well.. Either by setting the carry after the sbx, or by skip the sec and instead adjusting your 2nd parameter by one because the carry will always be clear after the sbx.. Depends on what data you have where at what times I guess
Still saves some cycles in those odd handy cases where things are all in the right place..
edit: As long is it generate opcode $AB it's the one