[A86] Re: assembly, programing and games
[Prev][Next][Index][Thread]
[A86] Re: assembly, programing and games
On Sat, 10 Mar 2001, Henk Poley wrote:
>
> Which of the "slots" are for RAM?
>
> At least on the Ti-82/83 the first two pages are for ROM only, the second
> two are (fixed) RAM-pages. I know of a system (?Spectrum?) which only has
> one page that can hold the RAM-pages (plus one that holds a fixed
> RAM-page).
>
> What should I do to prevent that my code is paged out???
> Some tips?
The TI-86 memory layout is essentially the following:
0000-3FFF holds a fixed ROM page
4000-7FFF can be switched to any RAM or ROM page
8000-BFFF can be switched to any RAM or ROM page
C000-FFFF holds a fixed RAM page
Since your program is loaded into the last block, you normally don't need
to worry about it being switched out at all.
Also note that the second block normally always points to ROM, and the
third always to RAM, though your program can change this. The second
block is where ROM calls go; normally, any ROM call you make will take
care of switching ROM pages in and out as needed.
Of course, if you want larger programs, then you might need to use the
8000-BFFF space also (when your program starts, most of the RAM page
switched into there can mostly be used for scratch space). Any ROM calls
accessing variables will probably switch that block. To deal with
this, you need to switch that page back in when you need it again,
and just don't call variable functions directly from it.
References: