[A83] Re: What the heck is RST???
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[A83] Re: What the heck is RST???
You can't use *any* system RAM (that includes flags, OP registers, graph
buffer, saveSScreen, appBackUpScreen, etc) while you have the page swapped,
and you can't use any ROM routine that would use system RAM (additionally,
TIOS checks to make sure a RAM page is loaded in port 7 in some places).
And yes, for restoring the page, you can get the current page that's there
with "in a,(7)", save that value, and output it to port 7 after you're
through.
-Dan Englender
> -----Original Message-----
> From: assembly-83-bounce@lists.ticalc.org
> [mailto:assembly-83-bounce@lists.ticalc.org]On Behalf Of Hyperbyte
> Sent: Saturday, July 07, 2001 2:27 PM
> To: assembly-83@lists.ticalc.org
> Subject: [A83] Re: What the heck is RST???
>
>
>
> Are there any implications to doin so?
> Since 8000h+ is normally used by flags and so, I assume they can't be used
> directly.
> Also, how do I get the ram page back.
> (I assume "in a,(07h)"
>
> is this correct to modify the pointers read from the VAT:
>
> hl contains the location in the 4000h range...
>
> res 6,h
> set 7,h
>
> ld a,(hl)
> ...
>
> It would be a whole lot faster than ld[a|c]indpaged'ing
>
> --Peter-Martijn
>
>
>
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