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.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Ableton Live 9.7.5 - 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
Maintenance 2.3.5 - System maintenance u...
Maintenance is a system maintenance and cleaning utility. It allows you to run miscellaneous tasks of system maintenance: Check the status of the hard disk Repair permissions Run periodic scripts... Read more
OnyX 3.3.8 - Maintenance and optimizatio...
OnyX is a multifunction utility that you can use to verify the startup disk and the structure of its system files, to run miscellaneous maintenance and cleaning tasks, to configure parameters in the... Read more
Merlin Project 4.3.1 - $289.00
Merlin Project is the leading professional project management software for OS X. If you plan complex projects on your Mac, you won’t get far with a simple list of tasks. Good planning raises... Read more
WhatsApp 0.2.6426 - Desktop client for W...
WhatsApp is the desktop client for WhatsApp Messenger, a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for... Read more
DiskCatalogMaker 7.2.5 - Catalog your di...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast Finder-like intuitive look and feel Super-fast search algorithm Can compress catalog data for... Read more
BBEdit 12.0.1 - 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
Hazel 4.2.2 - Create rules for organizin...
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 familiar... Read more
Hopper Disassembler 4.3.3- - Binary disa...
Hopper Disassembler is a binary disassembler, decompiler, and debugger for 32- and 64-bit executables. It will let you disassemble any binary you want, and provide you all the information about its... Read more
Adobe InCopy CC 2018 13.0.0.123 - Create...
InCopy CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous InCopy customer). Adobe InCopy CC 2018, ideal for large team projects... Read more

Guns Royale guide - beginner tips and tr...
If you've been itching to find a mobile battle royale game like Player Unknown's Battlegrounds, you're finally in luck. Guns Royale is a new survival shooter that takes all of the things you love about good ol' PUBG and puts it in a tidy mobile... | Read more »
What we know about Animal Crossing on mo...
At last, we'll be receiving some news about the mobile version of Animal Crossing in a special Nintendo Director at11 PM on October 24. There's been little word on the game since it was first announced, having been met with a series of delays.... | Read more »
Darts of Fury guide - how to rise in the...
Darts of Fury is a new, immensely absorbing darts game from indie studio Yakuto. It's darts in its purest form, but collectible darts and other upgrades give this game an addictive edge that's hard to shake. As your progress out of the beginner... | Read more »
ICEY (Games)
ICEY 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: ICEY is a 2D side-scrolling action game. As you follow the narrator's omnipresent voice, you will see through ICEY's eyes and learn the... | Read more »
The best new games we played this week -...
We've made it, folks. Another weekend is upon us. It's time to sit back and relax with the best new releases of the week. Puzzles, strategy RPGs, and arcade games abound this week. There's a lot of quality stuff to unpack this week, so let's hop... | Read more »
Wheels of Aurelia (Games)
Wheels of Aurelia 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: | Read more »
Halcyon 6: Starbase Commander guide - ti...
Halcyon 6 is a well-loved indie RPG with stellar tactical combat and some pretty good writing, too. It's now landed on the App Store, so mobile fans, if you're itching for a good intergalactic adventure, here's your game. Being a strategy RPG, the... | Read more »
Game of Thrones: Conquest guide - how to...
Fans of base building games might be excited to know that yet another entry in the genre has materialized - Game of Thrones: Conquest. Yes, you can now join the many kingdoms of the famed book series, or create your own, as you try to conquer... | Read more »
Halcyon 6: Starbase Commander (Games)
Halcyon 6: Starbase Commander 1.4.2.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.4.2.0 (iTunes) Description: An epic space strategy RPG with base building, deep tactical combat, crew management, alien diplomacy,... | Read more »
Legacy of Discord celebrates its 1 year...
It’s been a thrilling first year for fans of Legacy of Discord, the stunning PvP dungeon-crawling ARPG from YOOZOO Games, and now it’s time to celebrate the game’s first anniversary. The developers are amping up the festivities with some exciting... | Read more »

Price Scanner via MacPrices.net

27″ 3.4GHz iMac on sale for $1699, save $100
Amazon has the 27″ 3.4GHz iMac (MNE92LL/A) on sale today for $1699 including free shipping. Their price is $100 off MSRP, and it’s the lowest price available for this model (except for Apple’s $1529... Read more
Clearance 2016 15″ MacBook Pros available for...
B&H Photo has leftover 2016 15″ MacBook Pros available for up to $700 off original MSRP. Shipping is free, and B&H charges NY & NJ sales tax only: – 15″ 2.7GHz Touch Bar MacBook Pro Space... Read more
Save $100 on 13″ MacBook Airs, prices start a...
Adorama has 2017 13″ MacBook Airs on sale today for $100 off MSRP including free shipping. Adorama charges NY & NJ sales tax only: – 13″ 1.8GHz/128GB MacBook Air (MQD32LL/A): $899, $100 off MSRP... Read more
1.4GHz Mac mini available for $399, $100 off...
TigerDirect has the 1.4GHz Mac mini on sale today for $399 including free shipping. Their price is $100 off MSRP, and it’s the lowest price available for this model. Although currently out of stock,... Read more
21″ 2.3GHz iMac on sale for $999, save $100
MacMall has the 21″ 2.3GHz iMac (MMQA2LL/A) on sale today for $999 including free shipping. Their price is $100 off MSRP, and it’s the lowest price available for this model. Read more
12″ iPad Pros on sale for $50 off MSRP, no ta...
Adorama has 12″ iPad Pros on sale today for $50 off MSRP. Shipping is free, and Adorama charges sales tax in NY & NJ only: – 12″ 64GB iPad Pro: $749, save $50 – 12″ 256GB iPad Pro: $899, save $50... Read more
9″ iPads on sale for $30 off, starting at $29...
MacMall has 9″ iPads on sale for $30 off including free shipping: – 9″ 32GB iPad: $299 – 9″ 128GB iPad: $399 Read more
Apple restocks full line of refurbished 13″ M...
Apple has restocked a full line of Apple Certified Refurbished 2017 13″ MacBook Pros for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is free.... Read more
13″ 3.1GHz/256GB MacBook Pro on sale for $167...
Amazon has the 2017 13″ 3.1GHz/256GB Space Gray MacBook Pro on sale today for $121 off MSRP including free shipping: – 13″ 3.1GHz/256GB Space Gray MacBook Pro (MPXV2LL/A): $1678 $121 off MSRP Keep an... Read more
13″ MacBook Pros on sale for up to $120 off M...
B&H Photo has 2017 13″ MacBook Pros in stock today and on sale for up to $120 off MSRP, each including free shipping plus NY & NJ sales tax only: – 13-inch 2.3GHz/128GB Space Gray 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
Project Engineer, *Apple* Education Profess...
Project Engineer, Apple Education Professional Services Job Number: 113143353New York City, New York, United StatesPosted: Oct. 17, 2017Weekly Hours: 40.00 Job Read more
Commerce Software Engineer, *Apple* Media P...
Commerce Software Engineer, Apple Media Products Job Number: 113092072New York City, New York, United StatesPosted: Oct. 19, 2017Weekly Hours: 40.00 Job Summary With Read more
Engineering Manager, *Apple* Retail Enginee...
# Engineering Manager, Apple Retail Engineering Job Number: 58139948 Santa Clara Valley, California, United States Posted: 20-Oct-2017 Weekly Hours: 40.00 **Job 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.