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

5 slither.io mash-ups we'd love to...
If there's one thing that slither.io has proved, it's that the addictive gameplay of Agar.io can be transplanted onto basically anything and it will still be good fun. It wouldn't be surprising if we saw other developers jumping on the bandwagon,... | Read more »
How to navigate the terrain in Sky Charm...
Sky Charms is a whimsical match-'em up adventure that uses creative level design to really ramp up the difficulty. [Read more] | Read more »
Victorious Knight (Games)
Victorious Knight 1.3 Device: iOS Universal Category: Games Price: $1.99, Version: 1.3 (iTunes) Description: New challenges awaits you! Experience fresh RPG experience with a unique combat mechanic, packed with high quality 3D... | Read more »
Agent Gumball - Roguelike Spy Game (Gam...
Agent Gumball - Roguelike Spy Game 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Someone’s been spying on Gumball. What the what?! Two can play at that game! GO UNDERCOVERSneak past enemy... | Read more »
Runaway Toad (Games)
Runaway Toad 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: It ain’t easy bein’ green! Tap, hold, and swipe to help Toad hop to safety in this gorgeous new action game from the creators of... | Read more »
PsyCard (Games)
PsyCard 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: From the makers och Card City Nights, Progress To 100 and Ittle Dew PSYCARD is a minesweeper-like game set in a cozy cyberpunk... | Read more »
Sago Mini Robot Party (Education)
Sago Mini Robot Party 1.0 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0 (iTunes) Description: -- Children's Technology Review Editor's Choice -- | Read more »
How to get a high score in every level o...
Sky Charms is an adorable match three puzzler that provides a decent challenge thanks to its creative level design. It regularly presents something new, forcing you to think on your feet. [Read more] | Read more »
Apestorm: Full Bananas (Games)
Apestorm: Full Bananas 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: ***Launch sale – limited time only!*** Fugitive Apes have taken to the skies in search of revenge after humans have... | Read more »
How to create bigger words in Spellspire
Words have power. At least they do in Spellspire,a game about blasting out magical attacks by making words out of a jumble of letters. And it's a lot of fun. But if you want to be the best, you're going to have to think tactically when you start... | Read more »

Price Scanner via MacPrices.net

Aleratec Releases Mac Software Upgrade for 1...
California based Aleratec Inc., designer, developer and manufacturer of Portable Device Management (PDM) charge/sync products for mobile devices and professional-grade duplicators for hard disk... Read more
Sale! Amazon offers 27-inch iMac, 13-inch 2.9...
Amazon has the 27″ 3.2GHz 5K iMac and the 13″ 3.9GHz Retina MacBook Pro on sale for $300 off MSRP, each including free shipping, for a limited time: - 27″ 3.2GHz/1TB HD 5K iMac (model MK462LL/A): $... Read more
Apple refurbished 13-inch Retina MacBook Pros...
Apple has Certified Refurbished 13″ Retina MacBook Pros available for up to $270 off the cost of new models. An Apple one-year warranty is included with each model, and shipping is free: - 13″ 2.7GHz... Read more
13-inch 2.7GHz/128GB Retina MacBook Pro on sa...
Take $200 off MSRP on the price of a new 13″ 2.7GHz/128GB Retina MacBook Pro (model MF839LL/A) at Amazon. Shipping is free: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1099.99 $200 off MSRP Act now if... Read more
Apple refurbished clearance 15-inch Retina Ma...
Apple has Certified Refurbished 2014 15″ 2.2GHz Retina MacBook Pros available for $1609, $390 off original MSRP. Apple’s one-year warranty is included, and shipping is free. They have refurbished 15... Read more
27-inch 5K iMacs on sale for up to $150 off M...
B&H Photo has 27″ 5K iMacs on sale for up to $150 off MSRP including free shipping plus NY sales tax only: - 27″ 3.3GHz iMac 5K: $2199 $100 off MSRP - 27″ 3.2GHz/1TB Fusion iMac 5K: $1849.99 $150... Read more
What Does The Refreshed 12-Inch MacBook Tell...
A lot of commentators are complaining that Apple’s update of the 12-Inch MacBook last week is a bit of a damp squib. I don’t know what they were expecting, since it would be very unlike Apple to do a... Read more
Free Wittify Keyboard Now Available On The Ap...
A team of Harvard Business School students have announced that the Wittify Keyboard, a new app utility for iOS devices, is now available on the Apple App Store. The Wittify keyboard and application... Read more
Apple Reports First Year-Over-Year Quarterly...
Apple on TUesday announced financial results for its fiscal 2016 second quarter ending March 26, 2016. The Company posted quarterly revenue of $50.6 billion and quarterly net income of $10.5 billion... Read more
13-inch 2.7GHz Retina MacBook Pros on sale fo...
Take $130-$150 off MSRP on the price of a new 13″ 2.7GHz Retina MacBook Pro at Amazon. Shipping is free: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1169 $130 off MSRP - 13″ 2.7GHz/256GB Retina MacBook... Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Solutions Consultant - Apple (United...
# Apple Solutions Consultant Job Number: 48260200 Phoenix, Arizona, United States Posted: Apr. 22, 2016 Weekly Hours: 40.00 **Job Summary** As an Apple Solutions Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
Simply Mac *Apple* Specialist- Service Repa...
Simply Mac is the largest premier retailer of Apple products in the nation. In order to support our growing customer base, we are currently looking for a driven Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.