Questions about Playfield hardware and memory allocation

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1 total messages Started by Brett Coon Tue, 08 Jan 1991 20:45

#7945

Author: Brett Coon
Date: Tue, 08 Jan 1991 20:45

26 lines
1783 bytes

Question 1:
I recently modified a program so that instead of opening a low resolution
screen using 320x200 pixel bitplanes, I now open a lo-res screen using 640x200
pixel bitplanes, leaving 1/2 of each bitplane undisplayed.  I am doing double-
buffered animation on the bitplanes, which involves blitting into the un-
displayed bitplanes and then calling MakeScreen and RethinkDisplay.  For some
unknown reason, when I changed the size of my bitplanes but nothing else, my
animation rate decreased.  Does anyone know why?  Do the system routines take
longer to compute the copper lists when the bitplanes are larger than the
screen?  Or does the playfield DMA use extra memory cycles due to the non-
zero modulo?

Question 2:
Each time I run my program, I have 88 bytes less fast memory than before I
ran it.  I suspect this is just a result of memory fragmentation requiring
extra structures to track the free memory, but I'd like to be sure.  Are there
any programs available that can be used to make sure a given user program 
isn't leaving any memory allocated when it terminates?

Thanks for you help,
-brett

-- 
|Brett Coon           |  uunet!smosjc!brett                       |
|S-MOS Systems, Inc.  |  "Very exciting... as a luggage problem." |
|San Jose, CA         |            -Joe Vs. The Volcano           |

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