TweetFollow Us on Twitter

Aug 93 Tips, Tidbits
Volume Number:9
Issue Number:8
Column Tag:Tips & Tidbits

Tips & Tidbits

By Neil Ticktin, Editor-in-Chief

This column is your opportunity to spread the word about little bits of information that you find out about. These tidbits can be programming related or they can be user tips that are particularly useful to programmers.

MacTech Magazine will pay $25 for every tip used, and $50 for the Tip of the Month. Or you can take your award in orders or subscriptions.

To submit a tip, send in a letter to the magazine. E-mail is our preferred method, but feel free to send something via the US Mail. See page two for all addresses. If you do send snail mail, enclose a printed copy and a disk copy of the letter so that it does not have to be retyped.

Tip of the Month

If you log a MacsBug disassembly to a file the instructions are saved in the form:

     +0000  40809A7C   MOVEC    CACR,D1  | 4E7A 1002
     +0004  40809A80   ADDQ.W   #$8,D1   | 5041

One day I got sick of editing disassembled code, especially the code I wanted to recompile later. I wrote an MPW script to edit MacsBug disassembly log file into code that is easy to read and recompile, like this:

 MOVEC  CACR,D1
 ADDQ.W #$8,D1

Here is the script to do this. For those of you who don't know, the "#" character indicates a comment to be ignored by MPW.

#STEP1
format -f geneva -s 9 -t 26 #Set font, font size, tab size
find •  #Go to beginning of file
Loop    #Execute lines within loop repeatedly

 # Next line makes a selection of: spaces that are followed 
 # by a "+" all text between that and the next several 
 # spaces, And all text between the previous two and the next 
 # several spaces. Selects everything in front of the Opcode 
 # (MOVEC). Example - Selection between "" 
 # "  +0000 40809A7C "MOVEC CACR,D1 | 4E7A 1002
find  /" "++/:/" "+/:/" "+/
replace § "t"   #Replace the selection with a tab
find /" "+/ #Select the spaces after the Opcode
replace § "t"   #Replace the selection with a tab
find /" "+/:/ /  #Selection starts after the Operand 
 #(CACR,D1) and ends at the end of the line
replace § ""#Replace above selection with nothing
End#Loop if not at the end of the file

#STEP 2 - Clean up all RTS instructions
find •
Loop    #Loop until end of file reached
find /RTS/#Find an "RTS" string
find /t/:/ /    #Select all text after "RTS" to end of line
replace § ""#Replace with nothing
End

Execute STEP1 and STEP2 separately! In MPW, make the window that contains your disassemble routine the target window - click on it and then click back to the window that contains the above script. Select the lines following STEP1 and hit the "Enter" key. Then select STEP2 and hit Enter again. Your code should nicely align into the format shown above. The formatted code needs little editing before it can be recompiled.

- Greg Pribyl

Incline Village, Nevada

An Anonymouse Tip

According to Inside Macintosh Volume VI, the Macintosh File Manager is fully implemented in A/UX. This may be true when accessing Macintosh volumes. However, if you are writing to a Unix partition there is a subtle difference in behavior which can cause headaches.

If you set the logical end-of-file to zero, using a call such as "PBSetEOF", you might assume that the file position would automatically be set to zero as well, so that if you subsequently write to the file the data will be written starting at the zero position. This is in fact what happens if the file is on a Mac volume.

However, if it's on a UNIX volume, you get a nasty surprise. The file position is evidently NOT changed by the call to "PBSetEOF". Thus, subsequent writing will begin at the old position, which may not be zero. Example: You have a file of 1 megabyte which you want to overwrite with new data and the position happens to be at the end of the file. You set the logical end-of-file to zero, the File Manager reports no error, and so you go ahead and write the new data (again with no error reported). You discover that the file now contains a megabyte of null characters followed by the new data! This is a quick way to fill a disk with garbage!

MORAL: Explicitly set the file position to zero whenever you set the logical end-of-file to zero. And in general, always set the position to less than or equal to the logical end-of-file whenever you reduce the latter.

- Anonymous(e)

Hiding from MacsBug

Under System 7, if you place MacsBug's resources in the system sub-folder called Preferences, Macsbug will ignore the resource file during startup. Place the MacsBug resources in the system folder only!

This is useful if you want to hide these resources from MacsBug.

- Greg Pribyl

Incline Village, Nevada

Making use of a fast Tool

The StreamEdit tool introduced with MPW 3.2 doesn’t actually add a great deal of functionality to MPW. However, its main advantage is that it’s fast. If you have any shell scripts that do repetitive string manipulations, you can usually speed them up by rewriting them to use StreamEdit.

For example, in one of my projects, I have a special shell script to construct the makefile. Among other things, this script scans a dependencies file, with lines that look like

Module1 Module2 Type

to indicate that “Module1” imports something from “Module2” (“Type” indicates whether the dependency is in the definition or implementation module).

The script used to scan this file by opening it in the editor and using Find commands, followed by Catenate commands to read from the current selection. It used to take about 15 minutes to execute. After I rewrote it to use StreamEdit, it took 90 seconds.

Even a simple thing like generating a rule to compile all the source files in the current directory can benefit from StreamEdit. Here’s the old way I used to build the object library:

Set Ident '[A-Za-z0-9]+'
Echo -n 'MyModLib.o ƒ'
For ThisModule in "{Mods}" .mod
 (Evaluate "{ThisModule}" =~ 
 / :({Ident})®1.mod/) 
 >Dev:Null
 Echo -n 
' 'ntt'"{Objs}"'{®1}'.mod.o'
End # For

And here’s the new way:

# 2
Set Ident '[A-Za-z0-9]+'
Echo -n 'MyModLib.o ƒ'
Files "{Mods}" .mod | 
 StreamEdit -d -e 
 "/:({Ident})®1.mod/ "
"print ' '; print -n"
" 'tt"{Objs}"'®1'.mod.o'"

Another advantage of StreamEdit is that, by avoiding use of editor commands like Open and Find, your script can execute in the background under ToolServer.

- Lawrence D’Oliveiro

Computer Services Dept.

University of Waikato

Hamilton, New Zealand

 
AAPL
$99.76
Apple Inc.
+2.09
MSFT
$44.08
Microsoft Corpora
+0.45
GOOG
$520.84
Google Inc.
+9.67

MacTech Search:
Community Search:

Software Updates via MacUpdate

Macgo Blu-ray Player 2.10.9.1750 - Blu-r...
Macgo Mac Blu-ray Player can bring you the most unforgettable Blu-ray experience on your Mac. Overview Macgo Mac Blu-ray Player can satisfy just about every need you could possibly have in a Blu-ray... Read more
Apple iOS 8.1 - The latest version of Ap...
The latest version of iOS can be downloaded through iTunes. Apple iOS 8 comes with big updates to apps you use every day, like Messages and Photos. A whole new way to share content with your family.... Read more
TechTool Pro 7.0.5 - Hard drive and syst...
TechTool Pro is now 7, and this is the most advanced version of the acclaimed Macintosh troubleshooting utility created in its 20-year history. Micromat has redeveloped TechTool Pro 7 to be fully 64... Read more
PDFKey Pro 4.0.2 - Edit and print passwo...
PDFKey Pro can unlock PDF documents protected for printing and copying when you've forgotten your password. It can now also protect your PDF files with a password to prevent unauthorized access and/... Read more
Yasu 2.9.1 - System maintenance app; per...
Yasu was originally created with System Administrators who service large groups of workstations in mind, Yasu (Yet Another System Utility) was made to do a specific group of maintenance tasks... Read more
Hazel 3.3 - Create rules for organizing...
Hazel is your personal housekeeper, organizing and cleaning folders based on rules you define. Hazel can also manage your trash and uninstall your applications. Organize your files using a... Read more
Autopano Giga 3.7 - Stitch multiple imag...
Autopano Giga allows you to stitch 2, 20, or 2,000 images. Version 3.0 integrates impressive new features that will definitely make you adopt Autopano Pro or Autopano Giga: Choose between 9... Read more
MenuMeters 1.8 - CPU, memory, disk, and...
MenuMeters is a set of CPU, memory, disk, and network monitoring tools for Mac OS X. Although there are numerous other programs which do the same thing, none had quite the feature set I was looking... Read more
Coda 2.5 - One-window Web development su...
Coda is a powerful Web editor that puts everything in one place. An editor. Terminal. CSS. Files. With Coda 2, we went beyond expectations. With loads of new, much-requested features, a few... Read more
Arq 4.6.1 - Online backup to Google Driv...
Arq is super-easy online backup for the Mac. Back up to your own Google Drive storage (15GB free storage), your own Amazon Glacier ($.01/GB per month storage) or S3, or any SFTP server. Arq backs up... Read more

Latest Forum Discussions

See All

This Week at 148Apps: October 13-17, 201...
Expert App Reviewers   So little time and so very many apps. What’s a poor iPhone/iPad lover to do? Fortunately, 148Apps is here to give you the rundown on the latest and greatest releases. And we even have a tremendous back catalog of reviews; just... | Read more »
Angry Birds Transformers Review
Angry Birds Transformers Review By Jennifer Allen on October 20th, 2014 Our Rating: :: TRANSFORMED BIRDSUniversal App - Designed for iPhone and iPad Transformed in a way you wouldn’t expect, Angry Birds Transformers is a quite... | Read more »
GAMEVIL Announces the Upcoming Launch of...
GAMEVIL Announces the Upcoming Launch of Mark of the Dragon Posted by Jessica Fisher on October 20th, 2014 [ permalink ] Mark of the Dragon, by GAMEVIL, put | Read more »
Interview With the Angry Birds Transform...
Angry Birds Transformers recently transformed and rolled out worldwide. This run-and-gun title is a hit with young Transformers fans, but the ample references to classic Transformers fandom has also earned it a place in the hearts of long-time... | Read more »
Find Free Food on Campus with Ypay
Find Free Food on Campus with Ypay Posted by Jessica Fisher on October 20th, 2014 [ permalink ] iPhone App - Designed for the iPhone, compatible with the iPad | Read more »
Strung Along Review
Strung Along Review By Jordan Minor on October 20th, 2014 Our Rating: :: GOT NO STRINGSUniversal App - Designed for iPhone and iPad A cool gimmick and a great art style keep Strung Along from completely falling apart.   | Read more »
P2P file transferring app Send Anywhere...
File sharing services like Dropbox have security issues. Email attachments can be problematic when it comes to sharing large files. USB dongles don’t fit into your phone. Send Anywhere, a peer-to-peer file transferring application, solves all of... | Read more »
Zero Age Review
Zero Age Review By Jordan Minor on October 20th, 2014 Our Rating: :: MORE THAN ZEROiPad Only App - Designed for the iPad With its mind-bending puzzles and spellbinding visuals, Zero Age has it all.   | Read more »
Hay Ewe Review
Hay Ewe Review By Campbell Bird on October 20th, 2014 Our Rating: :: SAVE YOUR SHEEPLEUniversal App - Designed for iPhone and iPad Pave the way for your flock in this line drawing puzzle game from the creators of Worms.   | Read more »
My Very Hungry Caterpillar (Education)
My Very Hungry Caterpillar 1.0.0 Device: iOS Universal Category: Education Price: $3.99, Version: 1.0.0 (iTunes) Description: Care for your very own Very Hungry Caterpillar! My Very Hungry Caterpillar will captivate you as he crawls... | Read more »

Price Scanner via MacPrices.net

2013 15-inch 2.0GHz Retina MacBook Pro availa...
B&H Photo has leftover previous-generation 15″ 2.0GHz Retina MacBook Pros now available for $1599 including free shipping plus NY sales tax only. Their price is $400 off original MSRP. B&H... Read more
Updated iPad Prices
We’ve updated our iPad Air Price Tracker and our iPad mini Price Tracker with the latest information on prices and availability from Apple and other resellers, including the new iPad Air 2 and the... Read more
Apple Pay Available to Millions of Visa Cardh...
Visa Inc. brings secure, convenient payments to iPad Air 2 and iPad mini 3as well as iPhone 6 and 6 Plus. Starting October 20th, eligible Visa cardholders in the U.S. will be able to use Apple Pay,... Read more
Textkraft Pocket – the missing TextEdit for i...
infovole GmbH has announced the release and immediate availability of Textkraft Pocket 1.0, a professional text editor and note taking app for Apple’s iPhone. In March 2014 rumors were all about... Read more
C Spire to offer iPad Air 2 and iPad mini 3,...
C Spire on Friday announced that it will offer iPad Air 2 and iPad mini 3, both with Wi-Fi + Cellular, on its 4G+ LTE network in the coming weeks. C Spire will offer the new iPads with a range of... Read more
Belkin Announces Full Line of Keyboards and C...
Belkin International has unveiled a new lineup of keyboard cases and accessories for Apple’s newest iPads, featuring three QODE keyboards and a collection of thin, lightweight folios for both the... Read more
Verizon offers new iPad Air 2 preorders for $...
Verizon Wireless is accepting preorders for the new iPad Air 2, cellular models, for $100 off MSRP with a 2-year service agreement: - 16GB iPad Air 2 WiFi + Cellular: $529.99 - 64GB iPad Air 2 WiFi... Read more
Price drops on refurbished Mac minis, now ava...
The Apple Store has dropped prices on Apple Certified Refurbished previous-generation Mac minis, with models now available starting at $419. Apple’s one-year warranty is included with each mini, and... Read more
Apple refurbished 2014 MacBook Airs available...
The Apple Store has Apple Certified Refurbished 2014 MacBook Airs available for up to $180 off the cost of new models. An Apple one-year warranty is included with each MacBook, and shipping is free.... Read more
Refurbished 2013 MacBook Pros available for u...
The Apple Store has Apple Certified Refurbished 13″ and 15″ MacBook Pros available starting at $929. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.5GHz MacBook Pros (4GB RAM/... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Position Opening at *Apple* - Apple (United...
…customers purchase our products, you're the one who helps them get more out of their new Apple technology. Your day in the Apple Store is filled with a range of Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** At the Apple Store, you connect business professionals and entrepreneurs with the tools they need in order to put Apple solutions to work in their Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** The Apple Store is a retail environment like no other - uniquely focused on delivering amazing customer experiences. As an Expert, you introduce people Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** As businesses discover the power of Apple computers and mobile devices, it's your job - as a Solutions Engineer - to show them how to introduce these Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.