[A86] Re: Next question for the rom expert
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[A86] Re: Next question for the rom expert
Yeah, the rom is not a model of efficiency.
If you're gonna directly use _OPS, you have to make sure the high bit is
set and you have to make sure the right ram page is loaded.
_LOAD_OPS_ASIC/_load_ram_ops can do both of these for you. The rom
always clears the high bit again before storing it, but I don't think
that matters.
If you really want to do things right, you should check to make sure
there's enough space available on the stack. This will only matter in
very strange circumstances, tho. I'd probly ignore it.
_CHKMEM_PG1 will generate a memory error if there is less than hl bytes
available between the _FPS and _OPS pointers. On return from
_CHKMEM_PG1, regs are:
de = hl in
a is preserved
hl = (_OPS)-(_FPS)-hl in-1
bc=(_FPS)
-josh
On Thu, 30 Aug 2001 13:58:11 -0400 Aaron <acurti1@umbc.edu> writes:
>
> It seems like it would be better to write my own code than to use
> the
> 2-byte push calls. Something like...
>
> ld de,(_OPS)
> ld hl,_OP1+9
> ld bc,10
> lddr
> ld (_OPS),de
>
> ...which wouldn't be in the same format, but that doesn't matter.
> It just would have been nicer to have rom calls that do the whole
> thing... Though $57d5 and $5d8b look to have those routines on rom
> 1.3 as well.
>
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