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

Latest Forum Discussions

See All

Top Mobile Game Discounts
Every day, we pick out a curated list of the best mobile discounts on the App Store and post them here. This list won't be comprehensive, but it every game on it is recommended. Feel free to check out the coverage we did on them in the links... | Read more »
Price of Glory unleashes its 1.4 Alpha u...
As much as we all probably dislike Maths as a subject, we do have to hand it to geometry for giving us the good old Hexgrid, home of some of the best strategy games. One such example, Price of Glory, has dropped its 1.4 Alpha update, stocked full... | Read more »
The SLC 2025 kicks off this month to cro...
Ever since the Solo Leveling: Arise Championship 2025 was announced, I have been looking forward to it. The promotional clip they released a month or two back showed crowds going absolutely nuts for the previous competitions, so imagine the... | Read more »
Dive into some early Magicpunk fun as Cr...
Excellent news for fans of steampunk and magic; the Precursor Test for Magicpunk MMORPG Crystal of Atlan opens today. This rather fancy way of saying beta test will remain open until March 5th and is available for PC - boo - and Android devices -... | Read more »
Prepare to get your mind melted as Evang...
If you are a fan of sci-fi shooters and incredibly weird, mind-bending anime series, then you are in for a treat, as Goddess of Victory: Nikke is gearing up for its second collaboration with Evangelion. We were also treated to an upcoming... | Read more »
Square Enix gives with one hand and slap...
We have something of a mixed bag coming over from Square Enix HQ today. Two of their mobile games are revelling in life with new events keeping them alive, whilst another has been thrown onto the ever-growing discard pile Square is building. I... | Read more »
Let the world burn as you have some fest...
It is time to leave the world burning once again as you take a much-needed break from that whole “hero” lark and enjoy some celebrations in Genshin Impact. Version 5.4, Moonlight Amidst Dreams, will see you in Inazuma to attend the Mikawa Flower... | Read more »
Full Moon Over the Abyssal Sea lands on...
Aether Gazer has announced its latest major update, and it is one of the loveliest event names I have ever heard. Full Moon Over the Abyssal Sea is an amazing name, and it comes loaded with two side stories, a new S-grade Modifier, and some fancy... | Read more »
Open your own eatery for all the forest...
Very important question; when you read the title Zoo Restaurant, do you also immediately think of running a restaurant in which you cook Zoo animals as the course? I will just assume yes. Anyway, come June 23rd we will all be able to start up our... | Read more »
Crystal of Atlan opens registration for...
Nuverse was prominently featured in the last month for all the wrong reasons with the USA TikTok debacle, but now it is putting all that behind it and preparing for the Crystal of Atlan beta test. Taking place between February 18th and March 5th,... | Read more »

Price Scanner via MacPrices.net

AT&T is offering a 65% discount on the ne...
AT&T is offering the new iPhone 16e for up to 65% off their monthly finance fee with 36-months of service. No trade-in is required. Discount is applied via monthly bill credits over the 36 month... Read more
Use this code to get a free iPhone 13 at Visi...
For a limited time, use code SWEETDEAL to get a free 128GB iPhone 13 Visible, Verizon’s low-cost wireless cell service, Visible. Deal is valid when you purchase the Visible+ annual plan. Free... Read more
M4 Mac minis on sale for $50-$80 off MSRP at...
B&H Photo has M4 Mac minis in stock and on sale right now for $50 to $80 off Apple’s MSRP, each including free 1-2 day shipping to most US addresses: – M4 Mac mini (16GB/256GB): $549, $50 off... Read more
Buy an iPhone 16 at Boost Mobile and get one...
Boost Mobile, an MVNO using AT&T and T-Mobile’s networks, is offering one year of free Unlimited service with the purchase of any iPhone 16. Purchase the iPhone at standard MSRP, and then choose... Read more
Get an iPhone 15 for only $299 at Boost Mobil...
Boost Mobile, an MVNO using AT&T and T-Mobile’s networks, is offering the 128GB iPhone 15 for $299.99 including service with their Unlimited Premium plan (50GB of premium data, $60/month), or $20... Read more
Unreal Mobile is offering $100 off any new iP...
Unreal Mobile, an MVNO using AT&T and T-Mobile’s networks, is offering a $100 discount on any new iPhone with service. This includes new iPhone 16 models as well as iPhone 15, 14, 13, and SE... Read more
Apple drops prices on clearance iPhone 14 mod...
With today’s introduction of the new iPhone 16e, Apple has discontinued the iPhone 14, 14 Pro, and SE. In response, Apple has dropped prices on unlocked, Certified Refurbished, iPhone 14 models to a... Read more
B&H has 16-inch M4 Max MacBook Pros on sa...
B&H Photo is offering a $360-$410 discount on new 16-inch MacBook Pros with M4 Max CPUs right now. B&H offers free 1-2 day shipping to most US addresses: – 16″ M4 Max MacBook Pro (36GB/1TB/... Read more
Amazon is offering a $100 discount on the M4...
Amazon has the M4 Pro Mac mini discounted $100 off MSRP right now. Shipping is free. Their price is the lowest currently available for this popular mini: – Mac mini M4 Pro (24GB/512GB): $1299, $100... Read more
B&H continues to offer $150-$220 discount...
B&H Photo has 14-inch M4 MacBook Pros on sale for $150-$220 off MSRP. B&H offers free 1-2 day shipping to most US addresses: – 14″ M4 MacBook Pro (16GB/512GB): $1449, $150 off MSRP – 14″ M4... Read more

Jobs Board

All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.