TweetFollow Us on Twitter

GoodbyE Kiss
Volume Number:3
Issue Number:2
Column Tag:Tech Notes

GoodbyE Kiss

by Dan Weston

I'd like to inform the Mac community of a bug in the generic desk accessories that appear in my book, The Complete Book of Macintosh Assembly Language Programming, Vol I. Kirk Austin pointed out to me that the desk accessories crashed when receiving a goodbye kiss. The goodbye kiss is supposed to let your desk accessory clean up after itself if the application over which the accessory is running is terminated. For example, if your DA maintained open disk files or messed with low memory globals, you would normally close the files and reset the globals when a user closed the desk accessory. The goodbye kiss is provided by the Mac system software for those cases where the user quits an application without first closing the desk accessories. The underlying application doesn't need to be concerned with the goodbye kiss; it is handled totally by the Mac system software as it reinitializes the heap for the next program.

If you want your desk accessory to receive the goodbye kiss you must set bit #12 of the first word in the DA header. When an application terminates, the system software looks at each open desk accessory and sends a goodbye kiss if the appropriate bit is set in the DA header.

The goodbye kiss is a good idea. It prevents your desk accessory from being blown away without warning. The problem is that Inside Macintosh doesn't document how the goodbye kiss is implemented. In my book, I said that the goodbye kiss invoked the desk accessory's close routine. Now, after investigating a little further as a result of Kirk's letter, I find that the goodbye kiss doesn't invoke the close routine. Instead, the goodbye kiss is a control call with CSCode = -1. This causes big problems for my DA code because I use a jump table based on the belief that CSCode will ALWAYS be between 64 and 73. When the -1 CSCode hits the jump table it heads for ozone city; reach for the reset button.

The solution is to put a special case at the beginning of the control routine to watch for the goodbye control call and route it around the jump table (or just disable the goodbye call in the header, as Kirk did).

The modified code section follows:

;--------------------------------- 
; Control handles the control messages, which are the heart
; of the driver. Code values range from 64-73 (*** and -1
; for goodbye kiss ***) enter with pointer to DCE in A1 
; and pointer to Paramblock in A0 

Control 
 
 MOVEM.LA3-A4,-(SP); preserve A3 - A4  
 MOVE.L A1,A4    ; keep DCE ptr in A4 
 MOVE.L A0,A3    ; keep Pblock ptr in A3
 MOVE.W CSCode(A3),D0; get control opCode Pblock 
 ;******* 
 CMP.W  #-1,D0   ; is this the goodbye kiss? 
 BEQ    DoGoodbye; goodbye routine 
 ;******* 
 SUB.W  #64,D0   ; adjust range to 0-9 
 ADD.W  D0,D0    ; multiply by 2 for table 
 MOVE.W ControlTable(D0),D0 ; offset to routine 
 JMP    ControlTable(D0)  ; jump to it  

;---------- Offset table for Control routines --------- 
; **almost** all possible control messages that can be sent to
; a DA are here. All the routines mentioned here should 
; return by branching to CtlDone. 

ControlTable:
   
DC.W  DoEvent-ControlTable; an event (64) 
DC.W  DoPeriodic-ControlTable ; a periodic interupt (65) 
DC.W  DoCursor-ControlTable ; adjust cursor on DA wind (66) DC.W
 DoMenu-ControlTable ; menu selection (67) 
DC.W  DoUndo-ControlTable ; undo (68)  
DC.W  CtlDone-ControlTable; *** code 69 is not used *** DC.W   DoCut-ControlTable
 ; cut (70)
DC.W  DoCopy-ControlTable ; copy (71) 
DC.W  DoPaste-ControlTable; paste (72) 
DC.W  DoClear-ControlTable; clear (73)  

;--------------------------------------------   
CtlDone:  
 MOVE.L A4,A1    ; return DCE ptr to A1
 MOVE.L A3,A0    ; return PBlock ptr to A0
 MOVEM.L(SP)+,A3-A4; A3 - A4 restored 

 MOVE.W #0,D0    ; no error 
 RTS    ; go back to calling program 

;----------------------------------------------------   
DoGoodBye:
 MOVE.L A4,A1    ; return DCE ptr to A1
 MOVE.L A3,A0    ; return PBlock ptr to A0
 MOVEM.L(SP)+,A3-A4; A3 - A4 restored  
 MOVE.W #0,D0    ; no error
 MOVE.L JIODone,-(SP); return vector for asynch calls 
 RTS    ; go back to calling program 
 
 BRA.S  CtlDone  
;-------------------------------------------------------- 

One other detail that is important to note is that the goodbye kiss is an asynchronous control call. All other calls to desk accessories are synchronous, which means that they can return with a simple RTS. Asynchronous calls, on the other hand, must return via the JIODone routine. The low memery global JIODone, holds a pointer to this system routine, which clears the request from the I/O queue. We move this pointer onto the stack and then RTS. This routes our return through the JIODone routine.

Thanks to Kirk for bringing this to my attention. If anyone else has bugs to report from the book I'd love to hear about them. As best I can, I'll fix the bugs and post the information here in Mactutor.

 
AAPL
$102.50
Apple Inc.
+0.00
MSFT
$45.43
Microsoft Corpora
+0.00
GOOG
$571.60
Google Inc.
+0.00

MacTech Search:
Community Search:

Software Updates via MacUpdate

Mac DVDRipper Pro 5.0 - Copy, backup, an...
Mac DVDRipper Pro is the DVD backup solution that lets you protect your DVDs from scratches, save your batteries by reading your movies from your hard disk, manage your collection with just a few... Read more
pwSafe 3.1 - Secure password management...
pwSafe provides simple and secure password management across devices and computers. pwSafe uses iCloud to keep your password databases backed-up and synced between Macs and iOS devices. It is... Read more
StatsBar 1.8 - Monitor system processes...
StatsBar gives you a comprehensive and detailed analysis of the following areas of your Mac: CPU usage Memory usage Disk usage Network and bandwidth usage Battery power and health (MacBooks only)... Read more
Path Finder 6.5.5 - Powerful, award-winn...
Path Finder is a file browser that combines the familiar Finder interface with the powerful utilities and innovative features. Just a small selection of the Path Finder 6 feature set: Dual pane... Read more
QuarkXPress 10.2.1 - Desktop publishing...
With QuarkXPress, you can communicate in all the ways you need to -- and always look professional -- in print and digital media, all in a single tool. Features include: Easy to Use -- QuarkXPress is... Read more
Skype 6.19.0.450 - Voice-over-internet p...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
VueScan 9.4.41 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
Cloud 3.0.0 - File sharing from your men...
Cloud is simple file sharing for the Mac. Drag a file from your Mac to the CloudApp icon in the menubar and we take care of the rest. A link to the file will automatically be copied to your clipboard... Read more
LibreOffice 4.3.1.2 - 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
SlingPlayer Plugin 3.3.20.505 - Browser...
SlingPlayer is the screen interface software that works hand-in-hand with the hardware inside the Slingbox to make your TV viewing experience just like that at home. It features an array of... Read more

Latest Forum Discussions

See All

The Manhattan Project Review
The Manhattan Project Review By Andrew Fisher on September 2nd, 2014 Our Rating: :: ROCKET SCIENCEUniversal App - Designed for iPhone and iPad The Manhattan Project offers a great Euro-style gameplay experience, but it is totally... | Read more »
Rhonna Designs Magic (Photography)
Rhonna Designs Magic 1.0 Device: iOS Universal Category: Photography Price: $1.99, Version: 1.0 (iTunes) Description: Want to sprinkle *magic* on your photos? With RD Magic, you can add colors, filters, light leaks, bokeh, edges,... | Read more »
This Week at 148Apps: August 25-29, 2014
Shiny Happy App Reviews   | Read more »
Qube Kingdom – Tips, Tricks, Strategies,...
Qube Kingdom is a tower defense game from DeNA. You rally your troops – magicians, archers, knights, barbarians, and others – and fight against an evil menace looking to dominate your kingdom of tiny squares. Planning a war isn’t easy, so here are a... | Read more »
Qube Kingdom Review
Qube Kingdom Review By Nadia Oxford on August 29th, 2014 Our Rating: :: KIND OF A SQUARE KINGDOMUniversal App - Designed for iPhone and iPad Qube Kingdom has cute visuals, but it’s a pretty basic tower defense game at heart.   | Read more »
Fire in the Hole Review
Fire in the Hole Review By Rob Thomas on August 29th, 2014 Our Rating: :: WALK THE PLANKUniversal App - Designed for iPhone and iPad Seafoam’s Fire in the Hole looks like a bright, 8-bit throwback, but there’s not enough booty to... | Read more »
Alien Creeps TD is Now Available Worldwi...
Alien Creeps TD is Now Available Worldwide Posted by Ellis Spice on August 29th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Dodo Master Review
Dodo Master Review By Jordan Minor on August 29th, 2014 Our Rating: :: NEST EGGiPad Only App - Designed for the iPad Dodo Master is tough but fair, and that’s what makes it a joy to play.   | Read more »
Motorsport Manager Review
Motorsport Manager Review By Lee Hamlet on August 29th, 2014 Our Rating: :: MARVELOUS MANAGEMENTUniversal App - Designed for iPhone and iPad Despite its depth and sense of tactical freedom, Motorsport Manager is one of the most... | Read more »
Motorsport Manager – Beginner Tips, Tric...
The world of Motorsport management can be an unforgiving and merciless one, so to help with some of the stress that comes with running a successful race team, here are a few hints and tips to leave your opponents in the dust. | Read more »

Price Scanner via MacPrices.net

Apple refurbished iPads available for up to $...
Apple is offering Certified Refurbished iPad Airs for up to $140 off MSRP. Apple’s one-year warranty is included with each model, and shipping is free. Stock tends to come and go with some of these... Read more
Are We Now In The Post-Post-PC Era?
A longtime and thoroughgoing laptop aficionado, I was more than a little dismayed by Steve Jobs’s declaration back in 2010 when he sprang the iPad on an unsuspecting world. that we’d entered a “post-... Read more
PC Outlook Improves, But 2014 Shipments Still...
According to the International Data Corporation (IDC) Worldwide Quarterly PC Tracker, worldwide PC shipments are expected to fall by -3.7 percent in 2014. To hat’s actually an improvement from the... Read more
IDC Lowers Tablet Sales Projections for 2014...
Following a second consecutive quarter of softer than expected demand, International Data Corporation (IDC) has lowered its worldwide tablet plus 2-in-1 forecast for 2014 to 233.1 million units. The... Read more
Apple now offering refurbished 21-inch 1.4GHz...
The Apple Store is now offering Apple Certified Refurbished 21″ 1.4GHz iMacs for $929 including free shipping plus Apple’s standard one-year warranty. Their price is $170 off the cost of new models,... Read more
Save $50 on the 2.5GHz Mac mini, on sale for...
B&H Photo has the 2.5GHz Mac mini on sale for $549.99 including free shipping. That’s $50 off MSRP, and B&H will also include a free copy of Parallels Desktop software. NY sales tax only. 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
The Rise of Phablets
Carlisle & Gallagher Consulting Group, a businesses and technology consulting firm focused solely on the financial services industry, has released an infographic depicting the convergence of... Read more
Bad Driver Database App Allows Good Drivers t...
Bad Driver Database 1.4 by Facile Group is a new iOS and Android app that lets users instantly input and see how many times a careless, reckless or just plain stupid driver has been added to the... Read more
Eddy – Cloud Music Player for iPhone/iPad Fre...
Ukraine based CapableBits announces the release of Eddy, its tiny, but smart and powerful cloud music player for iPhone and iPad that allows users to stream or download music directly from cloud... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Senior Event Manager, *Apple* Retail Market...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global event strategy. Delivering an overarching brand story; in-store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.