TweetFollow Us on Twitter

Mar 89 Letters
Volume Number:5
Issue Number:3
Column Tag:Letters

Letters

By David E. Smith, Editor & Publisher, MacTutor

INIT29 & Hpat Virsus Wanted!

Steve Sequist is requesting an infected disk with the new INIT29 and Hpat (nVir type) virus so he can update last month's Security Patrol anit-virus program to detect and destroy them. If you have one or both, please send an infected disk, clearly marked with a skull and crossbones, to MacTutor, PO Box 400, Placentia, CA 92670, attn: Virus! -Ed

Watch Cursor Revisited

Jan Eugenides

Waterbury Center, VT

David Stoops’ Animated Cursors from the December issue was interesting, but it had two deficiencies:

1) It was hard-coded for eight cursors, instead of obtaining the real number of cursors from the ‘acur’ resource,

2) It used SetUpA5 and RestoreA5, which should no longer be used.

I recoded the example in MPW C 3.0b1, with the modifications, and here is the result. I also changed to an ‘acur’ resource with an ID of 128, so as not to conflict with any system resources. The Rez source code for the watch ‘acur’ and the associated cursors are as follows:

/* 1 */

#include <Types.h>
#include <Resources.h>
#include <QuickDraw.h>
#include <OSUtils.h>
#include <Retrace.h>
#include <Memory.h>
#include <ToolUtils.h>
#include <Strings.h>
#include <Errors.h>

typedef struct {
 short  numCurs; /*number of cursor “frames” */
 short  whichCur;/*used as “frame” counter*/
 CursHandle Curs[1]; /*can actually be any number of cursors here*/
 }acur;
typedef acur*acurPtr,**acurHandle;

static acurHandleCurList;
static VBLTask   VBL;

pascal void AnimateWatch()  /*the VBL routine*/
{
long    oldA5;

oldA5 = SetCurrentA5();
if((*CurList)->whichCur >= (*CurList)->numCurs-1 )
 (*CurList)->whichCur = 0;
else
 (*CurList)->whichCur ++;
SetCursor(*((*CurList)->Curs[(*CurList)->whichCur]));
VBL.vblCount = 10;
SetA5(oldA5);
}

InitWatch()
{
short   curCount;

CurList = (acurHandle)GetResource(‘acur’,128);
for(curCount = 0; curCount < (*CurList)->numCurs; curCount++)
 (*CurList)->Curs[curCount] = GetCursor(HiWord((long)(*CurList)->Curs[curCount]));
(*CurList)->whichCur = 0;
}
StartWatch()
{
OSErr   err;

VBL.qType = vType;
VBL.vblAddr = (VBLProcPtr)AnimateWatch;
VBL.vblCount = 10;
VBL.vblPhase = 0;
err = VInstall((QElemPtr)&VBL);
}

StopWatch()
{
OSErr err;

err = VRemove((QElemPtr)&VBL);
}
/* 2 */

#include “types.r”

data ‘acur’ (128, locked, preload) {
 $”00 08 00 00 01 00 00 00 01 01 00 00 01 02 00 00"
 $”01 03 00 00 01 04 00 00 01 05 00 00 01 06 00 00"
 $”01 07 00 00"
};
resource ‘CURS’ (263, locked, preload) {
 $”3F 00 3F 00 3F 00 3F 00 40 80 80 40 90 40 88 60"
 $”9C 60 80 40 80 40 40 80 3F 00 3F 00 3F 00 3F”,
 $”3F 00 3F 00 3F 00 3F 00 7F 80 FF C0 FF C0 FF C0"
 $”FF C0 FF C0 FF C0 7F 80 3F 00 3F 00 3F 00 3F”,
 {8, 8}
};
resource ‘CURS’ (262, locked, preload) {
 $”3F 00 3F 00 3F 00 3F 00 40 80 80 40 80 40 80 60"
 $”BC 60 80 40 80 40 40 80 3F 00 3F 00 3F 00 3F”,
 $”3F 00 3F 00 3F 00 3F 00 7F 80 FF C0 FF C0 FF C0"
 $”FF C0 FF C0 FF C0 7F 80 3F 00 3F 00 3F 00 3F”,
 {8, 8}
};
resource ‘CURS’ (261, locked, preload) {
 $”3F 00 3F 00 3F 00 3F 00 40 80 80 40 80 40 80 60"
 $”9C 60 88 40 90 40 40 80 3F 00 3F 00 3F 00 3F”,
 $”3F 00 3F 00 3F 00 3F 00 7F 80 FF C0 FF C0 FF C0"
 $”FF C0 FF C0 FF C0 7F 80 3F 00 3F 00 3F 00 3F”,
 {8, 8}
};
resource ‘CURS’ (260, locked, preload) {
 $”3F 00 3F 00 3F 00 3F 00 40 80 80 40 80 40 80 60"
 $”9C 60 84 40 84 40 40 80 3F 00 3F 00 3F 00 3F”,
 $”3F 00 3F 00 3F 00 3F 00 7F 80 FF C0 FF C0 FF C0"
 $”FF C0 FF C0 FF C0 7F 80 3F 00 3F 00 3F 00 3F”,
 {8, 8}
};
resource ‘CURS’ (259, locked, preload) {
 $”3F 00 3F 00 3F 00 3F 00 40 80 80 40 80 40 80 60"
 $”9C 60 82 40 80 40 40 80 3F 00 3F 00 3F 00 3F”,
 $”3F 00 3F 00 3F 00 3F 00 7F 80 FF C0 FF C0 FF C0"
 $”FF C0 FF C0 FF C0 7F 80 3F 00 3F 00 3F 00 3F”,
 {8, 8}
};
resource ‘CURS’ (258, locked, preload) {
 $”3F 00 3F 00 3F 00 3F 00 40 80 80 40 80 40 80 60"
 $”9F 60 80 40 80 40 40 80 3F 00 3F 00 3F 00 3F”,
 $”3F 00 3F 00 3F 00 3F 00 7F 80 FF C0 FF C0 FF C0"
 $”FF C0 FF C0 FF C0 7F 80 3F 00 3F 00 3F 00 3F”,
 {8, 8}
};
resource ‘CURS’ (257, locked, preload) {
 $”3F 00 3F 00 3F 00 3F 00 40 80 80 40 81 40 82 60"
 $”9C 60 80 40 80 40 40 80 3F 00 3F 00 3F 00 3F”,
 $”3F 00 3F 00 3F 00 3F 00 7F 80 FF C0 FF C0 FF C0"
 $”FF C0 FF C0 FF C0 7F 80 3F 00 3F 00 3F 00 3F”,
 {8, 8}
};
resource ‘CURS’ (256, locked, preload) {
 $”3F 00 3F 00 3F 00 3F 00 40 80 84 40 84 40 84 60"
 $”9C 60 80 40 80 40 40 80 3F 00 3F 00 3F 00 3F”,
 $”3F 00 3F 00 3F 00 3F 00 7F 80 FF C0 FF C0 FF C0"
 $”FF C0 FF C0 FF C0 7F 80 3F 00 3F 00 3F 00 3F”,
 {8, 8}
};

Animated Cursors Again

Erny Tontlinger

Steinfort, Luxembourg

Here are some comments to David Stoops’ Animated Cursors from the December 1988 Letters Column.

There is an error in the procedure InitWatch. The cursor id should be replaced by the cursor handle in the loop this:

/* 3 */

Watch[watchcount] := GetCursor(HiWord(longint(Watch[watchcount])));

The correct structure of a ‘acur’ resource is:

/* 4 */

acur = record
 frames: integer; {Number of frames(cursors) }
 whichWatch : integer;
 Watch : array[1..99] of CursHandle
 { size depends on frames }
end;

Then instead of using a fixed number of eight cursors, use Watch^^.frames, which happens to be eight for the Finder.

The ‘acur’ and ‘CURS’ resources should be locked, otherwise the VBL task runs into troubles with the memory Manager. The Finder uses the ‘CURS’ id 4 (classic watch cursor), which in the System file is not locked. This cursor is also in ROM, from the Mac Plus machines on, so it would be good to set RomMapInsert to mapTrue before calling GetCursor.

SetUpA5 and RestoreA5 might not work as expected under MultiFinder. The value of A5 should be placed in a position, other than CurrentA5 in low memory globals, where the application can find it from within the VBL task. See “Programmer’s Guide to MultiFinder” (APDA# KMB017) the chapter “The A5 world/VBL tasks”.

Now something different. Why is it so difficult to print READABLE program listing in MacTutor? Your desktop publishing program seems to have problems with regular spaced tab positions. Anyhow I appreciate MacTutor very much. [Basically, we convert the source into WriteNow in a 3 1/2" width single column with tabs set at every eighth of an inch. Then we place it into PageMaker. Here is where a number of problems occur as you surmised. PageMaker doesn't exactly import tab information correctly and we have to manually fix it. -Ed]

More Animated Watch Cursors

Rob Terrell

Chapel Hill, NC

In the December issue, you printed a letter that showed how to animate the watch cursor as a VBL task, which I thought was strange since a few issues back you printed another letter that gave a very good reason not to: a VBL task can go on and on while the application has crashed, and the poor user will be stuck thinking everything is okay.

A better way to implement the animated watch is through a unit that just takes a single call to increment the cursor. Support for this exists in TML Pascal II; for those not fortunate as to own TML, here’s a unit that does essentially the same thing:

{5}

Unit WatchItSpin;
(*Make sure you have copied the ‘acur’ and ‘CURS’ *)
(* resources from the Finder into your application *)
(* ResEdit is quite handy for this *)

Interface

Uses MemTypes, QuickDraw, OSintf, Toolintf;

type
 aCur = record
 whichWatch : longint;
 watch : array[1..8] of CursHandle;
 end;
 acurPtr = ^ acur;
 acurHandle = ^acurPtr;
var
 currentWatch : integer;
 WatchList : acurHandle;

Procedure InitSpinner;
Procedure SpinWatch;

Implementation

Procedure InitSpinner;
var
 count : integer;
begin
 watchList := acurHandle(GetResource(‘acur’,0));
 with watchList^^ do begin
 for count := 1 to 8 do
 Watch[count] := GetCursor(HiWord(longint( Watch[count])));
 whichWatch := 0;
 end;
end; (* InitSpinner *)

Procedure SpinWatch;
begin
 with WatchList^^ do begin
 if whichWatch >= 8 then whichWatch := 1
 else whichWatch := whichWatch + 1;
 SetCursor(Watch[whichWatch]^^);
 end;
end; (* SpinWatch *)
end.

Most of this code was simply taken from David Stoops’ letter. However, to use this, you call InitSpinner when you initialize everything else at the beginning of your program; then you call SpinWatch each time through a loop or time-consuming process to increment it. Not quite as nice as having a VBL take care of it, but this way, if you crash, the hands will stop.

Correction to CompareString

Steve Brecher

Sunnyvale, CA

In John S. Stokes III's CompareString routine (Jan 89 Letters), use of the Ext.W instruction introduces an error:

 Move.B (A0),D1  ; length of the first string
 Ext..W D1; dbra uses word

Ext.W propagates the value in bit 15 of the register through bits 16..31. Therefore, it will not have the desired effect of clearing bits 8..15. Ext.B would not work either for cases in which the string length is greater than 127,i.e. , negative considered as a signed byte; in such cases Ext.B would set bits 8..15, making the unsigned word value very large. To convert an unsigned byte value to a word in a register, first clear the word and then move the byte into it:

;6

 Clr.W  D1
 Move.B (A0),D1

Often programmers will write MoveQ #0,Dn instead of Clr.W Dn when the value in the upper word of the register either needs to be cleared also or is not of concern. MoveQ is always a longword operation.

A corrected CompareString would look like this:

;7

; A0  --> Pascal string 1
; A1 --> Pascal string 2
; Returns D0.L=1 if equal, 0 if not equal
; Alters A0-A1

CompareString:
 MoveQ  #0,D0
 Move.B (A0),D0  ;gross len - 1
@0 Cmp.B(A0)+,(A1)+ ;loop until...
 DBne D0,@0 ;...not equal or end
 Seq  D0;D0 := $FF if equal, else 0
 Neg.B  D0;D0 := 1 if equal, else 0
 Rts

The Move.B instruction puts the length byte of string 1 into D0. We want to compare the entire string structures, including their length bytes. The length of the entire structure--the gross length--of a string is the the number of text bytes, plus one for the length byte. For a DBxx instruction, we want the gross length - 1, which is just the value of the length byte.

We use the DBne instruction to control the loop. DBxx will branch to the start of the loop if either the test condition (in this case, “ne”) is false or the loop count is exhausted. Thus DBxx should be read as “branch until xx or counter expired.” When control falls through the DBne, we use the Seq instruction to condition D0 to the result of the last Cmp.B; DBxx instructions do not alter the condition codes. If the strings (including their lengths) are equal, the result of the last Cmp.B will be “eq” and the DBne will have not branched because the D1 counter expired. If the length bytes or contents of the strings are not equal, the last Cmp.B result will have been “ne” and the DBne will have not branched because its “until” condition was met.

[Steve Brecher is a long time friend of MacTutor. We welcome his comments and hope to hear more from him in the coming months. -Ed]

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

TotalFinder 1.12.2 - 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. Features... Read more
Duet 2.3.0.3 - Use your iPad as an exter...
Duet is the first app that allows you to use your iDevice as an extra display for your Mac using the Lightning or 30-pin cable. Note: This app requires a $9.99 iOS companion app. Version 2.3.0.3:... Read more
FileMaker Pro Advanced 18.0.3 - Powerful...
FileMaker Pro Advanced is the tool you use to create a custom app. You also use FileMaker Pro Advanced to access your app on a computer. Start by importing data from a spreadsheet or using a built-in... Read more
OsiriX Lite 10.0.6 - 3D medical image pr...
OsiriX Lite is an image processing software dedicated to DICOM images (".dcm" / ".DCM" extension) produced by medical equipment (MRI, CT, PET, PET-CT, ...) and confocal microscopy (LSM and BioRAD-PIC... Read more
Ableton Live 10.1.5 - Record music using...
Ableton Live lets you create and record music on your Mac. Use digital instruments, pre-recorded sounds, and sampled loops to arrange, produce, and perform your music like never before. Ableton Live... Read more
Burn 2.7.8 - Easily burn data, audio, vi...
Burn... There are a lot of ways to approach burning discs. Burn keeps it simple, but still offers a lot of advanced options. Create data discs with advanced data settings like, file permissions, the... Read more
Malwarebytes 4.0.30.3073 - Adware remova...
Malwarebytes (was AdwareMedic) helps you get your Mac experience back. Malwarebytes scans for and removes code that degrades system performance or attacks your system. Making your Mac once again your... Read more
Acorn 6.5.3 - Bitmap image editor.
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
Fantastical 2.5.13 - Create calendar eve...
Fantastical is the Mac calendar you'll actually enjoy using. Creating an event with Fantastical is quick, easy, and fun: Open Fantastical with a single click or keystroke Type in your event... Read more
A Better Finder Rename 11.05 - File, pho...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more

Latest Forum Discussions

See All

Eternal Warfare is a new idle clicker fo...
Idle games are a popular genre on mobile, they might not be to everyone's taste but they're made with such regularity and receive a lot of downloads, so it's hard to argue it's not big business. Eternal Warfare is set to join the sea of idle games... | Read more »
New heroes and balance updates set to ar...
It feels like Hearthstone: Battlegrounds only launched yesterday, and already the auto batter addition to Blizzard's megahit card game is set to receive new heroes and balance updates. [Read more] | Read more »
Pre-register for Hello Kitty AR: Kawaii...
Hello Kitty — the cute cat that launched a multi-billion-pound franchise — has been brought to life… sort of. Sanrio has teamed up with the Bublar Group to create a new mobile game that uses AR tech to turn the real world into Hello Kitty’s... | Read more »
Gorgeous and tranquil puzzler Spring Fal...
One-man indie studio SPARSE//GameDev has now launched its tranquil puzzler, Spring Falls. It's described as "a peaceful puzzle game about water, erosion, and watching things grow". [Read more] | Read more »
Black Desert Mobile gets an official rel...
Pearl Abyss has just announced that its highly-anticipated MMO, Black Desert Mobile, will launch globally for iOS and Android on December 11th. [Read more] | Read more »
Another Eden receives new a episode, cha...
Another Eden, WFS' popular RPG, has received another update that brings new story content to the game alongside a few new heroes to discover. [Read more] | Read more »
Overdox guide - Tips and tricks for begi...
Overdox is a clever battle royale that changes things up by adding MOBA mechanics and melee combat to the mix. This new hybrid game can be quite a bit to take in at first, so we’ve put together a list of tips to help you get a leg up on the... | Read more »
Roterra Extreme - Great Escape is a pers...
Roterra Extreme – Great Escape has been described by developers Dig-It Games as a mini-sequel to their acclaimed title Roterra: Flip the Fairytale. It continues that game's tradition of messing with which way is up, tasking you with solving... | Read more »
Hearthstone: Battlegrounds open beta lau...
Remember earlier this year when auto battlers were the latest hotness? We had Auto Chess, DOTA Underlords, Chess Rush, and more all gunning for our attention. They all had their own reasons to play, but, at least from where I'm standing, most... | Read more »
The House of Da Vinci 2 gets a new gamep...
The House of Da Vinci launched all the way back in 2017. Now, developer Blue Brain Games is gearing up to deliver a second dose of The Room-inspired puzzling. Some fresh details have now emerged, alongside the game's first official trailer. [Read... | Read more »

Price Scanner via MacPrices.net

B&H offers $100 discounts on 4-Core and 6...
B&H Photo has new 4-Core and 6-Core Mac minis in stock and on sale today for $100 off Apple’s MSRP. Prices start at $699. Overnight shipping is free to many addresses in the US: – 3.6GHz Quad-... Read more
Save $200 today on a 2019 13″ MacBook Air wit...
Apple has a full line of Certified Refurbished 2019 13″ MacBook Airs available starting at only $929 and up to $200 off the cost of new Airs. Each MacBook features a new outer case, comes with a... Read more
New Verizon Pre-Black Friday 2019 deal: Buy o...
Buy one new Apple iPhone 11 model or 2018 iPhone XS model at Verizon and get a second one for free. One new line of service required. Offer is valid from November 21, 2019 to November 27, 2019. Here... Read more
AirPods with Wireless Charging Case on sale t...
Abt Electronics has 2019 AirPods with the Wireless Charging Case on sale today for $163 shipped. Their price is $36 off Apple’s MSRP, and it’s currently the cheapest price for these AirPods from any... Read more
Apple continues to offer 2017 13″ Dual-Core n...
Apple has Certified Refurbished 2017 13″ 2.3GHz Dual-Core non-Touch Bar MacBook Pros still available starting at $1019. An standard Apple one-year warranty is included with each model, outer cases... Read more
Save up to $120 on the new 16″ MacBook Pro at...
Apple’s resellers are starting to receive stock of new 16″ MacBook Pros, and the first set of sales & deals are now available: (1) Amazon 16″ MacBook Pros start on sale for $100-$116 off Apple’s... Read more
Apple Watch Series 3 models on sale at Amazon...
Amazon has Apple Watch Series 3 GPS models on sale for $30 off MSRP, starting at only $169. There prices are the lowest we’ve ever seen for these models from any Apple reseller. Choose Amazon as the... Read more
The ‘Mac Potpourri’ Mailbag: Edition #1- Info...
COMMENTARY: 11.20.19- Welcome to the inaugural edition of the “Mac Potpourri” Mailbag where we take a look at correspondence received from readers of this column from all over the world who write in... Read more
13″ 2.4GHz MacBook Pros available for up to $...
Apple has a full line of Certified Refurbished 2019 13″ 2.4GHz 4-Core Touch Bar MacBook Pros available starting at $1529 and up to $300 off MSRP. Apple’s one-year warranty is included, shipping is... Read more
New at T-Mobile: Switch to T-Mobile, and get...
T-Mobile is offering a free 64GB iPhone 8 for new customers who switch to T-Mobile and open a new line of service. Eligible trade-in required, and discount applied over a 24 month period. The fine... Read more

Jobs Board

Best Buy *Apple* Computing Master - Best Bu...
**747303BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Store NUmber or Department:** 001413-Cypress-Store **Job Description:** **What Read more
*Apple* Mobility Pro - Best Buy (United Stat...
**743221BR** **Job Title:** Apple Mobility Pro **Job Category:** Store Associates **Store NUmber or Department:** 000230-Greenwood-Store **Job Description:** At Best Read more
*Apple* Mobility Pro - Best Buy (United Stat...
**747338BR** **Job Title:** Apple Mobility Pro **Job Category:** Store Associates **Store NUmber or Department:** 000254-Superstition Springs-Store **Job Read more
Best Buy *Apple* Computing Master - Best Bu...
**745516BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Store NUmber or Department:** 001101-Manhattan-Store **Job Read more
Best Buy *Apple* Computing Master - Best Bu...
**746655BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Store NUmber or Department:** 002518-Atlantic Center-Store **Job Description:** Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.