TweetFollow Us on Twitter

Call Register Routines
Volume Number:1
Issue Number:5
Column Tag:Undocumented procedure

Call register-based Toolbox/OS routines

By Steve Brecher

Macintosh Pascal provides a built-in procedure named Generic that is not documented. Generic permits you to call register-based Toolbox/OS routines. It can also be used to execute any machine language code that you have stored in a Pascal data structure. This article describes the use of the Generic procedure.

In effect, the following procedure is pre-declared:

procedure Generic(InstructionWord :integer;
                  VAR Registers : RegRcd);

“RegRcd” denotes a data structure consisting of 13 32-bit values -- five address register values (A0..A4), followed by eight data register values (D0..D7). The exact type of Registers is immaterial, i.e., you could declare:

var
 Registers : record
   A : array[0..4] of longint;
   D : array[0..7] of longint
  end;

Or in some cases you might prefer something like:

var
 Registers : record
   A0, A1, A2, A3, A4 : ^char;
   D0, D1, D2, D3, D4, D5, D6, D7 : longint
  end;

The register values that you pass to Generic are written to the MC68000 registers. Then the one-word instruction denoted by the InstructionWord argument is executed. Finally, your Registers structure is updated with the (possibly) new values of the MC68000 registers before Generic returns to your program.

Any registers that are not used by the machine language routine you’re invoking do not have to have their corresponding elements in the Registers data structure initialized. The machine language routine will have garbage in those registers (but, since it’s not using them, it won’t care).

Usually, Generic will be used to execute a register-based Toolbox/OS trap. In such cases the value you pass to Generic via the InstructionWord argument is the trap value. Here’s an example routine that resets the modem output port to establish new communications parameters:

type
  DataBitsT = (Five, Seven, Six, Eight);  
                               { ^--sic--^ }
  ParityT = (OddParity, NoParity, EvenParity);
  StopBitsT = (One, OnePointFive, Two);

 function ResetSer (Baud : longint;
         DataBits : DataBitsT;
         Parity : ParityT;
         StopBits : StopBitsT) : boolean;
{returns true if no error, false if modem}
{port hasn’t been opened yet}
{}
 const
   PBControl = $A004; {trap value}
   noErr = 0;
   ModemOutRefNum = -7;
   SerReset = 8;      {CScode}
{}
  var
   ParamBlockRec : record
     Filler : array[0..11] of integer;
     ioRefNum : integer;
     csCode : integer;
     csParam : integer
    end;
   Registers : record
     A : array[0..4] of longint;
     D : array[0..7] of longint
    end;
   serConfig : longint;
 begin {ResetSer}
  with ParamBlockRec do
   begin
    ioRefNum := ModemOutRefNum;
    csCode := SerReset;
    serConfig := trunc(114571.7 / baud -
                                              1.338395)
                 + 1024 * ord(DataBits)
                 + 4096 * (ord(Parity) + 1)
                 + 16384 * (ord(StopBits) + 1);
    csParam := loword(serConfig);
   end;
  Registers.A[0] := ord(@ParamBlockRec);
  Generic(PBControl, Registers);
  ResetSer := (Registers.D[0] = noErr)
 end; {ResetSer}

The InstructionWord argument to Generic does not have to be a trap value, however. It can be any 16-bit MC68000 instruction, as shown in the following example:

 procedure CallCode(VAR Result :integer);
{}
{This example assumes a global integer }
{array named Code which contains a       }
{machine language subroutine that takes}
{one VAR (address) argument on the       }
{stack.  CallCode calls the routine,        }
{passing it the address of the Result     }
{parameter. }
{}
 const
  JsrIndirectA0 = $4E90; { Jsr (A0) }
 var
  Registers : record
    A : array[0..4] of ^integer;
    D : array[0..7] of longint
   end;
  Glue : array[1..4] of integer;
 begin
{ MoveA.L (SP),A0 ;return addr }
  Glue[1] := $2057;
{ Move.L A2,(SP) ;ptr to Result }
  Glue[2] := $2E8A;
{ Move.L A0,-(SP) ;return addr }
  Glue[3] := $2F08;
{ Jmp (A1)        ;to subr in Code array }
  Glue[4] := $4ED1;
  with Registers do
   begin
    A[0] := @Glue[1];
    A[1] := @Code[1];
    A[2] := @Result;
   end;
  {Call Glue routine, which invokes Code}
  {routine...}
  Generic(JsrIndirectA0, Registers);
 end; {CallCode}

Scroll Rectangle Notes

(NOTE: did not appear with above article in MacTutor)

ScrollRect is a QuickDraw routine which scrolls a rectangle. Bits (pixels) scrolled out of the rectangle are lost, and the area near the side of the rectangle opposite to the scroll direction is filled with the current Grafport’s background pattern. [The rectangle defining the area to be scrolled must be larger than the screen object you wish to be moved by this procedure to allow room to be lost at the top.]

A Performance Note

ScrollRect will slow down by a factor of 3 or 4 if the scrolled rectangle includes one or more borders of the current Grafport’s portrect. For fast scrolling, assure that each side of the rectangle passed to ScrollRect is at least two pixels away from a border of the portrect.

A Usage Note

The UpdateRgn parameter (a region handle) passed to ScrollRect enables it to return to you the specification of the region that was vacated by scrolled bits and which ScrollRect filled with the background pattern. (Usually the vacated area will be a sub-rectangle of the scrolled rectangle; but it may be other than rectangular if an odd-shapped visRgn or clipRgn affects the ScrollRect.) The previous contents of the region (i.e., the data structure) are destroyed. If you don’t need to know the specification of the area filled with the background pattern (or if you already know), just allocate a dummy region (using NewRgn) and pass ScrollRect a handle to the dummy region. You can allocate the dummy region once at the beginning of your program; or you can allocate it before each call to ScrollRect and then use DisposRgn after each call to free the memory used by the region data structure.

 
AAPL
$112.65
Apple Inc.
+3.24
MSFT
$47.52
Microsoft Corpora
+1.78
GOOG
$511.10
Google Inc.
+6.21

MacTech Search:
Community Search:

Software Updates via MacUpdate

Mellel 3.3.7 - Powerful word processor w...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
ScreenFlow 5.0.1 - Create screen recordi...
Save 10% with the exclusive MacUpdate coupon code: AFMacUpdate10 Buy now! ScreenFlow is powerful, easy-to-use screencasting software for the Mac. With ScreenFlow you can record the contents of your... Read more
Simon 4.0 - Monitor changes and crashes...
Simon monitors websites and alerts you of crashes and changes. Select pages to monitor, choose your alert options, and customize your settings. Simon does the rest. Keep a watchful eye on your... Read more
BBEdit 11.0.2 - Powerful text and HTML e...
BBEdit is the leading professional HTML and text editor for the Mac. Specifically crafted in response to the needs of Web authors and software developers, this award-winning product provides a... Read more
ExpanDrive 4.2.1 - Access cloud storage...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
Adobe After Effects CC 2014 13.2 - Creat...
After Effects CC 2014 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous After Effects customer). After Effects CS6 is still available... Read more
Command-C 1.1.7 - Clipboard sharing tool...
Command-C is a revolutionary app which makes easy to share your clipboard between iOS and OS X using your local WiFi network, even if the app is not currently opened. Copy anything (text, pictures,... Read more
Tidy Up 4.0.2 - Find duplicate files and...
Tidy Up is a complete duplicate finder and disk-tidiness utility. With Tidy Up you can search for duplicate files and packages by the owner application, content, type, creator, extension, time... Read more
Typinator 6.3 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
GraphicConverter 9.5 - Graphics editor w...
GraphicConverter is an all-purpose image-editing program that can import 200 different graphic-based formats, edit the image, and export it to any of 80 available file formats. The high-end editing... Read more

Latest Forum Discussions

See All

Shift - Photo Filters Designed By You (...
Shift - Photo Filters Designed By You 1.0 Device: iOS Universal Category: Photography Price: $.99, Version: 1.0 (iTunes) Description: | Read more »
Elastic Drums (Music)
Elastic Drums 1.0 Device: iOS iPhone Category: Music Price: $3.99, Version: 1.0 (iTunes) Description: *** Introduction price 3,99$ instead of 7,99$ *** Elastic Drums is a music app with 6 channels of synthesized drum sounds, a step... | Read more »
Fireworks Simulator (Games)
Fireworks Simulator 1.0.8 Device: iOS Universal Category: Games Price: $.99, Version: 1.0.8 (iTunes) Description: *** 50% discount – For a short time only *** You can play Fireworks Simulator on these devices: - iPhone 5, 5s, 5c, 6,... | Read more »
Nicky's Gift (Games)
Nicky's Gift 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: Everybody! Merry Christmas! There's 48 levels in the game. Let's go! Nicky's Gift | Read more »
The Hit List — Simply Powerful Tasks, To...
The Hit List — Simply Powerful Tasks, To-Dos, Projects, & Reminders 2.0 Device: iOS iPhone Category: Productivity Price: $9.99, Version: 2.0 (iTunes) Description: >> LAUNCH SPECIAL: The Hit List 2 for iPhone is ONLY $9.99... | Read more »
Mahjong Journey Review
Mahjong Journey Review By Jennifer Allen on December 18th, 2014 Our Rating: :: STEADY MATCHINGiPad Only App - Designed for the iPad Aimed at the more laid back gamer, Mahjong Journey isn’t for everyone, but those looking for some... | Read more »
Emoji Type - custom keyboard with predic...
Emoji Type - custom keyboard with predictive emojis 0.4.0 Device: iOS iPhone Category: Utilities Price: $.99, Version: 0.4.0 (iTunes) Description: Emoji Type is custom keyboard for iOS 8 that auto suggests emojis as you type. ABOUT... | Read more »
Game of the Year 2014 – 148Apps Staff Pi...
The end of 2014 is almost here, which can only mean one thing. Okay it can mean a lot of things, but in this specific context it means Game of the Year lists! Which is why the 148Apps staff have all picked their favorites from the past year. And why... | Read more »
UponPixels Review
UponPixels Review By Jennifer Allen on December 18th, 2014 Our Rating: :: CREATIVE TYPOGRAPHYUniversal App - Designed for iPhone and iPad Add cool typography and objects to your photos with the easy to use UponPixels.   | Read more »
The Vikings are Coming! CastleStorm’s Ne...
The Vikings are Coming! CastleStorm’s New Update Adds a Survival Mode Posted by Jessica Fisher on December 18th, 2014 [ permalink ] | Read more »

Price Scanner via MacPrices.net

Save up to $400 on MacBooks with Apple Certif...
The Apple Store has Apple Certified Refurbished 2014 MacBook Pros and MacBook Airs available for up to $400 off the cost of new models. An Apple one-year warranty is included with each model, and... Read more
Save up to $300 on Macs, $30 on iPads with Ap...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
iOS and Android OS Targeted by Man-in-the-Mid...
Cloud services security provider Akamai Technologies, Inc. has released, through the company’s Prolexic Security Engineering & Research Team (PLXsert), a new cybersecurity threat advisory. The... Read more
KMI MIDI K-Board Great Gift for Amateur &...
The K-Board is a MIDI Nano keyboard for music creation for iPad, Android, And computers; the easiest way to make music with iPads & Android tablets, and Mac, Windows, or Linux computers. Ultra-... Read more
Amazon offers 15-inch 2.2GHz Retina MacBook P...
 Amazon.com has the 15″ 2.2GHz Retina MacBook Pro on sale for $1699 including free shipping. Their price is $300 off MSRP. Stock is limited, so act now if you’re interested. Read more
Holiday sales continue: MacBook Pros for up t...
 B&H Photo has new MacBook Pros on sale for up to $300 off MSRP as part of their Holiday pricing. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1699... Read more
Holiday sale: Mac minis available for up to $...
 B&H Photo has new 2014 Mac minis on sale for up to $80 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 1.4GHz Mac mini: $459 $40 off MSRP - 2.6GHz Mac mini: $629 $70 off... Read more
Google Search App For iOS Gets A Major Makeov...
Google has given iOS users an early Christmas present with a substantial update of it’s not-very-often-upgraded Google Search app. Google Search has been my go-to tool for Web searches since it was... Read more
ShopKeep Apple Pay And Chip Card Reader Avail...
ShopKeep, a cloud-based technology provider to more than 10,000 small business owners to manage retail shops and restaurants with iPads, has released its new Apple Pay and chip card reader. This... Read more
Holiday sale! 27-inch 5K iMac for $2299, save...
 B&H Photo has the 27″ 3.5GHz 5K iMac in stock today and on sale for $2299 including free shipping plus NY sales tax only. Their price is $200 off MSRP, and it’s the lowest price available for... Read more

Jobs Board

Project Manager, *Apple* Financial Services...
**Job Summary** Apple Financial Services (AFS) offers consumers, businesses and educational institutions ways to finance Apple purchases. We work with national and 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...
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* 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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.