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Jaguar Developer Weekly     September 22, 1995             Vol.1, No.14
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Jaguar CD Tips
--------------
68000 Interrupt Handlers are considered to be harmful with CD-ROM and
CD-ROM Emulation — As we all know, the 68000 is not considered the main
CPU in the Jaguar system.  Here is another reason not to use it for time
critical tasks.  During 68000 interrupt handling (for example in VBL)
the 68000 assumes a higher bus priority than the GPU.  At that priority,
the CD-read interrupt might read corrupted data by being kept from the
bus.  This type of corruption would not be reported by the CD BIOS.
This also can be a major reason for failure when using the CD Emulator.

We recommend the following:

•	Implement your Object list refresh completely in the GPU.  Refer
to the way CPKDEMO handles multiple interrupts in the GPU.

•	Do not use unnecessary 68000 interrupts while you are reading
from the CD.

•	If you are using 68000 interrupts, shorten the handler to the
bare minimum.  Lower the CPU Bus priority early in the 68000 interrupt
handler by writing to INT1 and INT2 (be aware that this makes interrupt
reentrancy possible).


Blitter Bugs & Warnings
-----------------------
1) Z Comparators fail in pixel mode without BKGWREN — If the blitter is
operating in pixel mode with the Z comparators enabled, then the
comparator will not inhibit writes correctly.  This can result in some
pixels being written incorrectly, or in pixels not being written that
should be.

The BKGWREN mode still works correctly.  If DSTEN and BKGWREN are both
set, then unmodified destination data is written back correctly.  This
will always solve the problem, although there is a speed penalty.


2) The Z registers can be shifted if SRCEN set — If doing a DSTWRZ blit
with SRCEN set, but not SRCENZ, and a set of Z values are written into
the Z registers, then the Z values get shifted as if they were read
source Z values.  This has the effect of shifting the integer parts and
shifting up some of the fractional parts into the integer fields.  The Z
shifting clearly should not be enabled unless SRCENZ is set, but in fact
it is enabled if SRCEN is set.

This only occurs if the source and destination are not aligned to the
same boundary within a phrase (i.e.  both aligned to 2 bytes past a
phrase boundary would be OK, but having one on a phrase boundary and the
other 4 bytes past a phrase boundary would not be OK).  The work-around
is therefore to pre-align the source data.


The JAGWIRE Network
A Letter To Jaguar Licensees & Developers From Atari's Don Thomas
-----------------------------------------------------------------
On October 6, 1995, Atari will unveil a new dimension of interactive
online support for Jaguar gamers, the JAGWIRE™ network.  This network
will blend the talents and resources of many powerful online
communications partners.  It can be your tool to help pre-sell and
support your Jaguar products.

One of the components of the JAGWIRE network will be Atari's new Jaguar
World Wide Web home page on the Internet.  This will feature exciting
news and information about products for the Jaguar from both Atari and
third-party publishers.

Another component of the JAGWIRE network is the naming of Compuserve as
Atari's official Commercial Online Support site.  In celebration, the
Atari Jaguar forum (GO JAGUAR) will be scheduling more conferences,
contests, and activities exclusively for Jaguar forum members.
Additionally, Compuserve will offer free access to the Jaguar forum for
Jaguar third-party partners who want to support their products online.

The JAGWIRE network is just around the corner and I could use your
help...

Press Releases — If you have one or more recent press releases you would
like us to add to our new JAGWIRE WEB Domain, please forward them
immediately to me via EMAIL at: 75300.1267@compuserve.com.

Press releases must be related to the Atari Jaguar in a way that
benefits or will benefit Jaguar gamers.  Press releases also must
pertain to licensed or approved products/distribution channels.  Press
releases should be fairly recent, but if you have an accurate one from a
few months back, feel free to contribute.  Feel free to create one or
more new ones for this purpose.

Atari reserves the right to choose between all those submitted and
although my intention would be to use all of them, I may choose not to
post one or more for any number of reasons.

When sending press releases to my address, please make the SUBJECT of
the message:

    RE: REPLY JAGWIRE PR

WWW Hot Links — I would also like to ask anyone who has an
Jaguar-related Web site AND who would like to exchange Hot Links to
please submit your Internet web address to me immediately.  I will add
to our Hot Links all those who add Atari’s to theirs.  Atari’s official
start date is October 6 and the link should be in place by that time.
Atari’s JAGWIRE domain is:

   http://www.atari.com

Please send me a brief message that explains the name of your
page/domain, what information related to the Jaguar may be found there
AND what the address is for people to get there (we can link).

If you know anyone that can benefit from these requests within the Atari
community, please feel free to pass it on privately.  I hope to hear
back from you SOON!

Don Thomas, Director of Customer Service,
Atari Corporation
75300.1267@compuserve.com




Path Specifications & The Jaguar Development Tools
--------------------------------------------------
Many of the tools in the Jaguar Developer's Kit for the MS-DOS platform
have been compiled with the GNU GCC C/C++ compiler.  Although there are
versions of GCC for most computer platforms in use today, the native
platform for GCC is UNIX, and this is reflected by the behavior of the
GCC standard C libraries.  UNIX uses a forward slash ("/") as a
directory path separator character, rather than the backslash ("\") used
by MS-DOS.  As a result, many of the Jaguar tools accept either style of
slash as valid path separator characters.

In most cases, you simply use standard MS-DOS backslashes in your
environment variables or MAKEFILEs, but there are some cases where using
a forward slash is required or preferred.  Specifically, it is
recommended that you use forward slashes for the environment variables
MACPATH and GCC_EXEC_PREFIX, as well as with the "-I" command line
switch for MADMAC.  In general, remember that both types of slashes are
used, and if you experience problems, you may be using the wrong type.



Updated Jaguar Synth & Music Driver Samples
-------------------------------------------
The three sample programs that demonstrate the use of the Jaguar Synth &
Music Driver have been updated to run more reliably and be easier to
understand.

First, the samples now use the standard Jaguar Startup Code.  Previous
versions did not contain proper startup code, which resulted in
inconsistent operation in many cases.

Second, the synthesizer patch info for each sample program was stored in
subdirectories of the main project file, but the exact layout was
different for each sample.  Now each sample's project directory contains
a single PATCHES directory which contains all of the various synthesizer
patch files required for the project.

Third, the filenames and file extensions used for the patch information
were not consistent from one sample program to the next, or even from
one patch to the next.  This has been reorganized so that the filenames
and file extensions are now consistent with each other and from program
to program.

Download the JAGSYN.ZIP archive file to get the new versions of the
sample programs.  Note also that the MUSIC.TXT file in the MUSICP.ZIP
archive has been updated to reflect the changes to the sample programs.


XMAS Season Deadlines for Jaguar Software Titles
------------------------------------------------
The production deadlines for the Christmas selling season are
approaching quickly.  Developers and publishers should keep in mind that
all cartridge-based products must be fully-tested and released into
production by October 5, and CD-based products by October 31, in order
to insure that your product is shipping in time for the Thanksgiving
sales weekend, the beginning of the Christmas selling season.  Remember
to allow at least 4 weeks for final testing.


New BBS Number
--------------
The Atari Software Development BBS is now running as a two line system.
The new number for both lines is (408) 541- 9164.


When Signing Onto the BBS For the First Time
--------------------------------------------
The very first time you log onto the Atari Software Development BBS, you
won't have access to the message bases or the file libraries with the
updates to the Jaguar developer kit files.  This is because the Atari
SDBBS is a closed system for developers only, and everybody who calls
must individually be given clearance before they can access these areas.

To get full access, it is imperative that you leave a detailed message
to the sysop that includes your full name, your company, telephone
number, and the name of the Jaguar project you are working on.

Failure to provide the proper information will result in your access
being delayed indefinitely.  So if you log on and leave a message that
just says something like "Hi, I'm Joe and I need access to the Jaguar
developer areas", you won't get it, because we will not have any means
of verifying who you are.  On the other hand, if you do leave the proper
information, full access should be granted within a day or two at most.


Use Atari's Standard Startup Code...
------------------------------------
Developers who are not already using Atari's standard startup code with
their projects need to be aware that failure to do so may result in
their software failing to work properly on the next-generation Jaguar
machines currently in development.

Atari's standard startup code initializes the Jaguar GPU & DSP,
interrupt vectors, and other hardware in a way that is known to be safe
on current and future machines.  It displays a simple opening graphic,
and jumps to your main program code, which would display any additional
title screens, play a introductory Cinepak film, or whatever else is
appropriate for your program.

Avoid making changes to the startup code.  In most cases, the only
acceptable modification is changing the startup picture.  If you think
further modifications are required, please bring them to Atari's
attention at the earliest possible stage of development so that either
they can be approved or an alternate method found.

Atari's startup code can be found in the SOURCE.ZIP archive available
online.  After you've decompressed the archive contents, the source
files will be in the \JAGUAR\SOURCE\STARTUP directory.


And Use Our Current EEPROM Code Too!
------------------------------------
Atari supplies standard routines for accessing a Jaguar cartridge's
EEPROM to store or retrieve high score info, user preferences, etc.  If
you are not using Atari's most current version of these routines, then
your program may not function correctly with new cartridge EEPROM
hardware which will soon be used on Jaguar cartridges.

The EEPROM routines are found in the SOURCE.ZIP archive, available for
downloading online.  The latest revision is from March 14, 1995.  This
extracts to the directory \JAGUAR\SOURCE\EEPROM.


Jaguar Tool Updates
-------------------
The Jaguar Developers Kit tools and related files listed below have been
updated recently.  You can download them from the Atari Software
Development BBS or from the Jaguar Developer library in the Atari Gaming
forum on Compuserve.

Jaguar EEPROM Library — September 22, 1995.  The actual code hasn't
changed since the March 15 revision, but there is now a 16-byte library
indentification string included at the beginning of the code.  Download
SOURCE.ZIP.

Jaguar CDROM Files — September 15, 1995.  This features the newest
version of the Cinepak FILMINFO utility, the latest MAKETRK utility
(Sept.  8) as well as a new version of the CD BIOS (v4.5) as well as
some changes to the included CDROM sample reader program, and changes to
the CD Boot Emulator.  Download CDROM.ZIP

Jaguar Synth & Music Driver — September 15, 1995.  This has a few minor
corrections from the Sept.  8 version.  Download JAGSYN.ZIP.

Jaguar Library Archive — September 8, 1995.  The JAGLIB.ZIP archive has
been updated to remove the older version of the 3D Graphics Library.  If
you haven't switched to the new library yet, give it a look.  The new 3D
library and sample code are in the JAGUAR\3D directory contained in
JAGLIB.ZIP

MADMAC Macro Assembler — September 1, 1995.  New version of MADMAC
includes Bitfield definitions.  See article for details.  Download
MACALN.ZIP for the MS-DOS version, STTOOLS.ZIP for the Atari version, or
LINUX.ZIP for the PC Linux version.

DB Debugger — September 1, 1995.  New versions of WDB and RDBJAG fixes a
problem reading COF files with very long symbol names.  Download
DBPC.ZIP for the MS-DOS version, STTOOLS.ZIP for the Atari version, or
LINUX.ZIP for the PC Linux version.

FILEFIX Utility — September 1, 1995.  New version of FILEFIX changes no
longer gives an error if program does not start at $802000.  Download
UTILPC.ZIP for the MS-DOS version, STTOOLS.ZIP for the Atari version.


Dev Kit Roadmap
---------------
To keep track of recent updates to the Jaguar Developer's Kit tools,
libraries, and other components, Atari maintains the file ROADMAP.TXT.
This file is posted online and is updated at the same time any of the
standard distribution archives from the Jaguar Developer's kit are
updated.


If you've missed previous issues...
-----------------------------------
then it's possible that we may not have a current fax number for you.
Just in case, please contact us with your current address, telephone and
fax numbers.  Also, consider that the better solution would be to
subscribe to the Jaguar Developer Weekly Via EMAIL.

The preferred method for Atari to send out the Jaguar
Developer Weekly is via EMAIL, but unfortunately, we don't
have a database of everybody's EMAIL addresses.  If you have
a current Internet or Compuserve EMAIL address, please send
a message to mfulton@atari.com so that we can add you to the
list of developers that receive the Jaguar Developer Weekly
via EMAIL instead of fax.  What you get each week will be
the ASCII text of the issue, plus an online readable version
(if there are graphics to go along with any of the
articles).


Back Issues Available
---------------------
Back-issues of the Jaguar Developer Weekly are available online in the
DEVNEWS.ZIP archive.  This archive file contains text-only versions of
all of the issues since the first edition.  This archive will be updated
with new issues as they come out.





+----------------------------------------------------------------------+
| If you have comments, questions, or suggestions regarding the Jaguar |
| Developer Weekly, please call Mike Fulton at Atari Corporation at    |
| (408) 745-8821, send a fax to (408) 745-2088, or send EMAIL to       |
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| "mfulton@atari.com".                                                 |
+----------------------------------------------------------------------+

