Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!jarthur!nntp-server.caltech.edu!toddpw
From: toddpw@nntp-server.caltech.edu (Todd P. Whitesel)
Newsgroups: comp.sys.apple2
Subject: Re: help optimizing asm routine (and help with GetCaretTime)
Message-ID: <1991May24.111453.27330@nntp-server.caltech.edu>
Date: 24 May 91 11:14:53 GMT
References: <3638@kluge.fiu.edu>
Organization: California Institute of Technology, Pasadena
Lines: 49

acmfiu@serss0.fiu.edu (ACMFIU) writes:

>below are three assembly routines. two i need help in optimizing and the
>third i need help to get it to work.

And how...

First, I suggest you install a heartbeat task and use it to tell your event
loop code when to blink. Read up in the Miscellaneous Tools chapter (I assume
you know where that is...), hearbeat tasks are quite useful and convenient
for this sort of thing.

>the next routine, 'scroll_rect', is used to scroll my off-screen grafport
>one line (line = length specified by ~line_height [height of line]). can
>anyone optimize this? the code is self-explanatory.

Well, if you want to make your source a lot easier to manage, make a macro
that represents one or more loop iterations and edit the macro. Then you
can experiment with faster unrolled code with far less stress than hand
editing 80 copies of the same fragment.

>the last routine, 'copy_grafport', is used to copy the data in an off-screen
>grafport to an on-screen grafport, namely my window. i also need this
>optimized.

>               _HideCursor

Ugh. There's a ShieldCursor vector for this. It's in a technote, left an
excercise for the reader.

>:6             ldy     ]x
>:4             lda     []off_image],y
>               sta     []image],y
>               dey
>               dey
>               bpl     :4

Jeezus. LHG at its slowest uses a loop like this. You can use MVP/MVN a lot
of the time (yes, you really can use them -- get sneaky), and most of the
time (except under Orca) you can map the stack into the shadowed graphics
page and romp pixels to the screen.

Sure it sounds sick but that's tough noogies. Think about it for a while and
then mail me. Don't listen to Tim Meekins, or your code won't work with
AppleTalk (in fact he's lucky it works at all -- do you EVER check to see
where the standard GrafPort is, Tim?).

Todd Whitesel
toddpw @ tybalt.caltech.edu