TweetFollow Us on Twitter

Apr 97 Tips

Volume Number: 13 (1997)
Issue Number: 4
Column Tag: Tips & Tidbits

Tips & Tidbits

By Steve Sisak

Debugging 68K Code Resources with MacsBug

I'm using a CDEF as an example here, but this technique can be quite useful in many situations.

I recently had the pleasure of writing a tiny application for an old client. There was actually more code in the custom CDEF than the app itself. Once it was all polished and "bug free" I took it to the client's site for a demo. Naturally, it crashed immediately on launch. Everything froze up and I had to do a hard reset. I strongly suspected my CDEF was the problem. Normally, I would put a DebugStr in the CDEF, recompile, and use MacsBug to find the problem. But this was a 4MB LCII. There was no chance of installing CodeWarrior and rebuilding the CDEF. However, the computer did have an old copy of ResEdit. The following is what I did.

1) I opened my application in ResEdit and used the GetInfo dialog to make my CDEF preloaded and locked. I then saved the file and quit ResEdit.

2) In MacsBug, I set an A-trap break on InitGraf.

atb _InitGraf

3) I launched my app. Since initializing QuickDraw is one of the first things my program does, my A-trap break fired and I dropped into MacsBug.

4) The MacOS automatically loads preloaded resources when the resource file is open, so I found my CDEF in memory and set a breakpoint. To find the resource, I typed "hd RS" (list all resources in the current heap).

The screen looked something like this

hd RS

Displaying the "Quick Launch" heap at 00192830

Start Length Tag Mstr Ptr Lock Prg Type ID

00194890 00000544 R 00192A00 L CODE 0001

00196872 00000A44 R 00192A04 L CDEF 0080

etc...

5) Since my CDEF was already loaded in memory, and locked down, I set a breakpoint at the beginning of the CDEF.

br 00196872

I then typed command-g to continue. My breakpoint was soon hit and the bug identified. I fixed the problem the next day and got paid. This technique can be used to set a breakpoint at the beginning of nearly any code resource.

Damon Cokenias
http://www.netgate.net/~cokenias

In the MacTech 13.02 (February 1997) we printed a tip from Bill Hayden that System 7.5.3 made it possible to navigate the Standard File dialog box by clicking items visible on the desktop. Since then, a number of readers have written to report they could not reproduce this behavior.

After trying a variety of system software releases, we have not found a publicly released version of the system exhibiting this behavior, although one reader has reported reproducing it on a version of System 7.5.3 release 2 but not 7.5.5.

We offer two possible explanations for the source of the tip. First is a freeware utility called "Click, there it is!", by Richard Cardona Utilities Group (now in version 1.0.7), which enables the behavior described in the tip. A second possible explanation is that the reported functionality may have been enabled in a developer release of system software, but removed from the final, public release.

In any case, we apologize for the error and thank everyone who took the time to report it, as well as those who have taken the time to submit tips - please keep them coming.

Best wishes,

--Steve

 
AAPL
$98.43
Apple Inc.
+0.05
MSFT
$43.41
Microsoft Corpora
-0.48
GOOG
$587.35
Google Inc.
+1.74

MacTech Search:
Community Search:

Software Updates via MacUpdate

Mellel 3.3.6 - Powerful word processor w...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
LibreOffice 4.3.0.4 - Free Open Source o...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
Freeway Pro 7.0 - Drag-and-drop Web desi...
Freeway Pro lets you build websites with speed and precision... without writing a line of code! With it's user-oriented drag-and-drop interface, Freeway Pro helps you piece together the website of... Read more
Drive Genius 3.2.4 - Powerful system uti...
Drive Genius is an OS X utility designed to provide unsurpassed storage management. Featuring an easy-to-use interface, Drive Genius is packed with powerful tools such as a drive optimizer, a... Read more
Vitamin-R 2.15 - Personal productivity t...
Vitamin-R creates the optimal conditions for your brain to work at its best by structuring your work into short bursts of distraction-free, highly focused activity alternating with opportunities for... Read more
Toast Titanium 12.0 - The ultimate media...
Toast Titanium goes way beyond the very basic burning in the Mac OS and iLife software, and sets the standard for burning CDs, DVDs, and now Blu-ray discs on the Mac. Create superior sounding audio... Read more
OS X Yosemite Wallpaper 1.0 - Desktop im...
OS X Yosemite Wallpaper is the gorgeous new background image for Apple's upcoming OS X 10.10 Yosemite. This wallpaper is available for all screen resolutions with a source file that measures 5,418... Read more
Acorn 4.4 - Bitmap image editor. (Demo)
Acorn is a new image editor built with one goal in mind - simplicity. Fast, easy, and fluid, Acorn provides the options you'll need without any overhead. Acorn feels right, and won't drain your bank... Read more
Bartender 1.2.20 - Organize your menu ba...
Bartender lets you organize your menu bar apps. Features: Lets you tidy your menu bar apps how you want. See your menu bar apps when you want. Hide the apps you need to run, but do not need to... Read more
TotalFinder 1.6.2 - Adds tabs, hotkeys,...
TotalFinder is a universally acclaimed navigational companion for your Mac. Enhance your Mac's Finder with features so smart and convenient, you won't believe you ever lived without them. Tab-based... Read more

Latest Forum Discussions

See All

Star Admiral Review
Star Admiral Review By Rob Thomas on July 30th, 2014 Our Rating: :: ADMIRABLE ADMIRALSUniversal App - Designed for iPhone and iPad While this new digital CCG may feel a bit familiar, Star Admiral offers a sci-fi twist and galaxy’s... | Read more »
Zap! Pow! Become a Badass Wizard in Phan...
Zap! Pow! | Read more »
Urban Trial Freestyle Review
Urban Trial Freestyle Review By Blake Grundman on July 30th, 2014 Our Rating: :: RIDIN' DIRTYUniversal App - Designed for iPhone and iPad A rough ride that has trouble keeping its wheels on the track.   | Read more »
Take Note! Noteshelf Has Recieved a Big...
Take Note! Noteshelf Has Recieved a Big Update. Posted by Jessica Fisher on July 30th, 2014 [ permalink ] iPad Only App - Designed for the iPad | Read more »
Cubama Review
Cubama Review By Nadia Oxford on July 30th, 2014 Our Rating: :: TETRIIIIIS IIIIIN SPAAAAACE!Universal App - Designed for iPhone and iPad With its addictive challenge and interesting premise, Cubama is frantic screen-tapping fun.   | Read more »
Become a Guardians of Galactic Peace Wit...
Become a Guardians of Galactic Peace With the New Spacefaring Sim, Kairobotica. Posted by Jessica Fisher on July 30th, 2014 [ permalink ] | Read more »
Soul Guardians: Age of Midgard Review
Soul Guardians: Age of Midgard Review By George Fagundes on July 30th, 2014 Our Rating: :: SO MUCH GRIND IT CRUNCHESUniversal App - Designed for iPhone and iPad Swords and trading cards are fun, right? So is Soul Guardians: Age of... | Read more »
NFL Fantasy Football App Redesigned Ahea...
NFL Fantasy Football App Redesigned Ahead of Upcoming 2014 Season Posted by Ellis Spice on July 30th, 2014 [ permalink ] | Read more »
Matter Review
Matter Review By Jennifer Allen on July 30th, 2014 Our Rating: :: ORIGINAL PHOTO MANIPULATIONUniversal App - Designed for iPhone and iPad Matter lets you add geometric 3d shapes to your images and manipulate things so each image... | Read more »
Note Review
Note Review By Jennifer Allen on July 29th, 2014 Our Rating: :: TOO SIMPLEiPhone App - Designed for the iPhone, compatible with the iPad Note is a note taking app that’s a little too short on features to be worth its asking price... | Read more »

Price Scanner via MacPrices.net

More iPad Upgrade Musings – The ‘Book Mystiqu...
Much discussed recently, what with Apple reporting iPad sales shrinkage over two consecutive quarters, is that it had apparently been widely assumed that tablet users would follow a two-year hardware... Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
Best Buy has the 13″ 2.5GHz MacBook Pro available for $999.99 on their online store. Choose free shipping or free instant local store pickup (if available). Their price is $100 off MSRP. Price is... Read more
Save up to $300 on an iMac with Apple refurbi...
The Apple Store has Apple Certified Refurbished iMacs available for up to $300 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free. These are the best prices on... Read more
WaterField Unveils 15″ Outback Solo & 13″...
Hard on the heels of Apple’s refreshed MacBook Pro Retina laptops announcement, WaterField Designs has unveiled a 15-inch version of the waxed-canvas and leather Outback Solo and a 13-inch version of... Read more
New Roxio Toast 12 Delivers Digital Media Pow...
Roxio Toast 12 is a hub for sharing digital media to virtually any platform or device. has introduced two new additions to its Roxio Toast product family – Roxio Toast 12 Titanium and Roxio Toast 12... Read more
The lowest prices on leftover Retina MacBook...
Best Buy has dropped prices on leftover 13″ and 15″ Retina MacBook Pros by up to $300 off original MSRP on their online store for a limited time. Choose free local store pickup (if available) or free... Read more
Apple Updates MacBook Pro with Retina Display...
Apple today updated its MacBook Pro with Retina display with faster processors and double the amount of memory in both entry-level configurations. MacBook Pro with Retina display features a Retina... Read more
Up to $250 price drop on leftover 15-inch Mac...
B&H Photo has dropped prices on 2013 15″ Retina MacBook Pros by as much as $250 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.3GHz Retina MacBook Pro: $2349... Read more
Updated MacBook Pro Price Trackers
We’ve updated our MacBook Pro Price Trackers with the latest information on prices, bundles, and availability on the new 2014 models from Apple’s authorized internet/catalog resellers as well as... Read more
Apple updates MacBook Pros with slightly fast...
Apple updated 13″ and 15″ Retina MacBook Pros today with slightly faster Haswell processors. 13″ models now ship with 8GB of RAM standard, while 15″ MacBook Pros ship with 16GB across the board. Most... Read more

Jobs Board

Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Sr. Product Leader, *Apple* Store Apps - Ap...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.