Path: utzoo!attcan!uunet!nih-csl!lhc!ncifcrf!haven!aplcen!samsung!usc!zaphod.mps.ohio-state.edu!wuarchive!psuvax1!psuvm!art100
From: ART100@psuvm.psu.edu (Andy Tefft)
Newsgroups: comp.sys.apple2
Subject: 8bit screen blanker
Message-ID: <90303.233006ART100@psuvm.psu.edu>
Date: 31 Oct 90 04:30:06 GMT
Organization: Penn State University
Lines: 38

Ok, making a little progress here.

I have the routines done that will save the screen status, save
screen info, restore the screen info and status, and bounce the
time around the screen (00:00 if time is not set).

How should I protect this thing in memory? I was going to
have podos allocate me some buffers and relocate into there.
The space taken up there will also include $400 bytes to store
the screen image. I would like to have prodos allocate a buffer
for that and release it when i'm done, but unfortunately
when you call freebuf it releases ALL buffers you got with
a getbuf, including the one the program resides in. There's
a trick in Ken Manly's prodos copy command (Nibble, Dec '85)
which keeps prodos from releasing buffers above a certain
point in memory, but it's nonstandard and I don't want to use it.
Does this bother anyone?

Second thing: any forseeable problems if I just get the time
from the prodos time locations at 49043 (hour) and 49042
(min)? This works with vblclock. Oh i should try it on my //e
which has a versacard in it. Yep, checks out ok.

Third thing: I know the //c has some convoluted and incomprehensible
way you can read the status of the single/double hires softwsitch
($c060 for double, $c05f for single). I have to set this to
single hi-res for this thing to work correctly (don't see why,
but it leaves clock trails on the screen if I don't). Would
it be poor to check the apple keys when the key is pressed to
exit the bllanked screen, and if an apple key is pressed use double
otherwise single hi res?  All the other important modes are switched
automatically.

I'm still figuring out a way to get into the input routine and
time the wait since last keypress. I don't want to re-write
keyin (cause I'm nervous about making it work under 40 and 80
columns both), but I might have to. Any suggestions (besides
"use interrupts!")?