TweetFollow Us on Twitter

Volume Number:6
Issue Number:6
Column Tag:Programmer's Forum


By Gerry H. Kenner, David Burggraaf, Salt Lake City, UT

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.


[Gerry Kenner is a conservative senior citizen who has been working with computers and writing scientific papers since 1962 when the era first began. David Burggraaf is a newcomer to the field who got his first computer (a Sinclair) in 1980 and hasn’t stopped being excited since. Suffice it to say that most of the ideas and all of the work involved in this project were done by David.]

With their fixed methods of entering, retrieving and manipulating data, code resource packages appear to be the ideal system of object oriented programming. In this case, the object is the code resource. The popularity of this concept is shown by the use of code resources under different names by 4th Dimension™(external objects), Excel™ (DDLs) and Hypercard™ (XCMDs and XFCNs). Further, pioneer systems for using code resources in standalone programs are becoming available, the first example being Serius89™ but other programs are not far behind.

A problem with this type of programming is that the libraries must be replicated whenever they are used in different code resources. Further, when doing code resources at least some compilers link in all functions in a library and not just the ones being used. This is in contrast to the smart linking which occurs when standalone applications are generated. Experience has shown us that the size of most code resources can be reduced by 50% while some can be reduced by as much as 70% or more if the library routines are removed.

This paper reports on a method for installing the libraries and a jump table to access them as a separate code resources and then using a simple series of calls to access them from other code resources (Hypercard XCMDs in this case).

The Project

The project consisted of putting all the library functions in two code resources of type “LIB “ called CodeLib and FCodeLib. Two code resources were used because the dispatch routines for functions which return arguments longer than 32 bits are different from the cases where the return value will fit in register D0. Included in each library is the code of the library functions and a dispatch routine (main()) to provide access to them. The “LIB “ type resources are loaded into Hypercard or stacks using ResEdit.

The .h file

The CodeLib.h file includes the necessary definitions and macros for setting up the libraries in XCMD projects. Included are the list of index variables for each function call (i.e., CLatoi, CLatol, etc.), macro definitions for redefining return parameters and library function call names (#define atoi(str) ((**idispatch) (CLatoi,(char*)(str))), and typedef void (**Vfunch) (CodeLib,...);, etc.) and the macro calls which are added to the XCMD project for incorporating the above material in source code.

Perhaps the best method for understanding the contents of this file is to follow the compilation and execution of the main routine of the XCMD following the addition of the special library code. First of all, the contents of CodeLib.h are read in. In addition to declaring the macros and index variables, this file defines the handles VFunch, IFunch, etc and declares extern global variables of these types (dispatch, idispatch, etc). When executed the macro CODELIB legitimitizes the extern declaration of these variables by declaring them within the XCMD.

LOADCODELIB() is a function which appears as follows when unfolded.

/* 1 */

if (!initCodeLib())
if (!initFCodeLib())

Its function is to determine whether the libraries are present, get handles to them and then lock the handles so the libraries won’t move. Otherwise it returns with nothing being done. The task of getting the handles is done by initCodeLib() and initFCodeLib. The initCodeLib macro is expanded to show how this is done.

/* 2 */

fdispatch = (Ffunch)GetResource(‘LIB ‘, 18000);
pdispatch = (Pfunch)fdispatch;
cdispatch = (Cfunch)pdispatch;
ldispatch = (Lfunch)cdispatch;
idispatch = (Ifunch)ldispatch;
dispatch = (Vfunch)idispatch;

Note that all the handles point to the same address.

With the above code in place, execution of a code line such as

/* 3 */

 TempInt = atoi(TempStr);

will result in the following at compilation time.

/* 4 */

 TempInt = ((**idispatch)(CLatoi, (char*)TempStr)));

When executed, this code will pass the address of idispatch, the value of the index CLatoi and the contents of TempStr to the library code resource.

A Special Case

An exception to the above ease of use are function calls such as sprintf which pass variable numbers of arguments. In these cases, the definitions in the CodeLib.h file serve as templates for inserting the code manually. For instance, the definition of sprintf(s,f) is ((**idispatch)(CLsprintf, (s), (f), ...)). When a statement such as sprintf(TempStr, “Good Day”) is encountered the programmer must replace it manually with ((**idispatch) (CLsprintf, TempStr, “Good Day”) using the definition as a guide.


This file shares the CodeLib.h file except it does not include the NOCODELIB definitions for redefining the library function call names. Addressing the library functions is taken care of by declaring the following code before the main routine is called.

/* 5 */

typedef void (*Function)(void);
FunctionfuncTable[ROUTINES + 1]

where the value of ROUTINES was declared in CodeLib.h. Values are assigned to the funcTable variable within the main routine as follows.

/* 6 */


It would be nice if these could be declared statically, but we have not been able to figure out a method for doing it.

There are two segments of assembly language code. The first segment replaces the calls RememberA4() and SetUpA4() which are not used because they shift things around on the stack. This code stores the current value of A4 and replaces it with the address of the main routine which is stored in A0 when the code is called. The second assembly language segment is a glue routine for configuring the stack before jumping to the desired library function.

/* 7 */

 asm  {
 move.l (a7)+, returnAddr;/*save return address*/
 move.w (a7)+, a1; /*remove index*/
 lea funcTable, a0;/*do jump to indexed subroutine*/
 jsr ([0,a0,a1.w*4],0);
 move.w a1, -(a7); /*restore stack and return*/
 move.l returnAddr, -(a7);
 move.l oldA4, a4; /*restore a4  */

It removes the return address and saves it before doing a jsr to the requested funcTable entry after which it is put back on the stack. The index value is also removed from the stack, placed in a1 for use as an offset and then replaced on the stack at the end of the call. The last line of code restores the old value of a4.


Note that there are six dispatch types although only four are used in this code. The remaining two are for functions which return floats and structures. Further functions can be added to by using the formats given. We have included the code of a sample Hypercard XCMD which uses the libraries or of a Hypercard stack to exercise the XCMD. Other examples are left as an exercise for the reader.

This project is written with THINK C. Similar code would be difficult though possible to implement in Pascal. An important point to note if you are using calls which use floating point arithmetic or call the printf type functions is that the standard ANSI-A4 library does not include floating point functions nor math functions. The math functions are gained by adding math.c to the ANSI-A4 library project. Floating point capabilities are added by opening the ansi-config.h file which is found in the source code of the ANSI-A4 project and commenting out the line #define _NOFLOATING_ and then recompiling the project under a different name such as ANSI-A4(f). Another point to remember is that other functions such as qsort and atof are also not part of the ANSI-A4 project and must be added if they are to be used.

If you have any questions David can be reached on internet at BURGGRAAF @

Installation Instructions:

1. Install the Library code resource wherever it is needed, i.e., as a code resource in your Hypercard stack.

2. Include the “CodeLib.h” header file before any of the functions in the code library are called.

3. Enter the line


before any function in the library is called. It must be typed outside of any function. It is a preprocessor declaration of the necessary global variables.

4. If they are not already part of your code put in the instructions RememberA0, SetUpA4 and RestoreA4, so that the above global variables can be used.

5. In the main function, at the beginning type the line.


This should be the first function call other than functions which setup registers for global variable access. (i.e., SetupA4()).

6. In the main function, at the end enter the line.


7. If present, remove any duplicate libraries which are present in your project.

8. Build the project.

Listing:  CodeLib.h

#ifndef _CODE_LIB_
#define _CODE_LIB_
typedef enum
 CLsqrt=1 /*Double/struct lib */
 } CodeLib;

#define ROUTINES 5
#define FROUTINES  1

#define atoi(str) ((**idispatch)(CLatoi,(char *)(str)))
#define atol(str) ((**ldispatch)(CLatol,(char *)(str)))
#define sprintf(s,f) ((**idispatch)(CLsprintf,(s),(f),...))
#define srand(s) ((**dispatch)(CLsrand,(unsigned)(s)))
#define strcpy(s1,s2) ((char *)((**pdispatch)(CLstrcpy,(char*)(s1),(char 
#define sqrt(d) ((**ddispatch)(CLsqrt, (double)(d)))

typedef void (**Vfunch)(CodeLib,...);
typedef int (**Ifunch)(CodeLib,...);
typedef long (**Lfunch)(CodeLib,...);
typedef char (**Cfunch)(CodeLib,...);
typedef float (**Ffunch)(CodeLib,...);
typedef double (**Dfunch)(CodeLib,...);
typedef void *(**Pfunch)(CodeLib,...);

#define CODELIB Vfunch dispatch;Ifunch idispatch;Lfunch ldispatch;Cfunch 
cdispatch;Ffunch fdispatch;Dfunch ddispatch;Pfunch pdispatch;
#ifndef NOTLLIB
#define initCodeLib() (dispatch=(Vfunch)(idispatch=(Ifunch)(ldispatch=(Lfunch)(cdispatch=( 
Cfunch)(pdispatch=(Pfunch)(fdispatch=(Ffunch)GetResource(‘LIB ‘, 18000)))))))
#define initcodeLib() 1
#endif CODELIB

#define initFCodeLib() (ddispatch=(Dfunch)GetResource(‘LIB ‘, 18001))
#define initFCodeLib() 1

#define LOADCODELIB() {if (!initCodeLib()) return;else HLock(dispatch);if 
(!initFCodeLib()) {HUnlock(dispatch);return;}else HLock(ddispatch);}
#define UNLOADCODELIB() {HUnlock(dispatch);HUnlock(ddispatch);}

extern Vfunch dispatch;
extern Ifunch idispatch;
extern Lfunch ldispatch;
extern Cfunch cdispatch;
extern Ffunch fdispatch;
extern Dfunch ddispatch;
extern Pfunch pdispatch;
Listing:  CodeLibDispatch.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include “CodeLib.h”

typedef void (*Function)(void);

long returnAddr, oldA4;
int funcIndex;
void dispatchErr(void);
Function funcTable[ROUTINES+1];
void main(void)
 { /* CodeLib routine*/
 asm  {
 move.l a4, a1;  /*setup a4 */
 move.l a0, a4;
 move.l a1, oldA4;
 asm  {
 move.l (a7)+, returnAddr;/*save return address*/
 move.w (a7)+, a1; /*remove index  */
 lea funcTable, a0;/*do jump to indexed subroutine*/
 jsr ([0,a0,a1.w*4],0);
 move.w a1, -(a7); /*restore stack and return*/
 move.l returnAddr, -(a7);
 move.l oldA4, a4; /*restore a4  */
 } /* Main*/

void dispatchErr(void)
Listing:  FCodeLibDispatch.c

#include <math.h>

#include “CodeLib.h”

typedef void (*Function)(void);

long returnAddr, oldA4, returnStruct;
int funcIndex;
void dispatchErr(void);
Function funcTable[FROUTINES+1];
void main(void)
 { /*CodeLib routine*/
 asm  {
 move.l a4, a1;  /*setup a4 */
 move.l a0, a4;
 move.l a1, oldA4;
 asm  {
 move.l (a7)+, returnAddr;/*save return address*/
 move.l (a7)+, returnStruct;/*save return StructPtr*/
 move.w (a7)+, a1; /*remove index  */
 move.l returnStruct, -(a7);/*put return StructPtr*/
 lea funcTable, a0;/*do jump to indexed subroutine*/
 jsr ([0,a0,a1.w*4],0);
 move.l (a7)+, returnStruct;/*get return structPtr*/
 move.w a1, -(a7); /*restore stack and return*/
 move.l returnStruct, -(a7);
 move.l returnAddr, -(a7);
 move.l oldA4, a4; /*restore a4  */
 } /* Main*/

void dispatchErr(void)

Listing: testCodeLib.c

#include “CodeLib.h”
#include “HyperXCmd.h”
#include “SetUpA4.h”


pascal void main(XCmdBlockPtr paramPtr)
 int    TempInt1, TempInt2;
 unsigned int  Seed;
 long   TempLong;
 StringHandle  TempHdl;
 double TempDouble1, TempDouble2;
 Ptr    TempPtr;
 Str255 TempStr;
 TempHdl = (StringHandle)NewHandle(256);
 TempPtr = *(paramPtr->params[0]);
 TempInt1 = atoi((char*)TempPtr);
 TempPtr = *(paramPtr->params[1]);
 TempLong = atol((char*)TempPtr);
 TempInt2 = (int)TempLong;
 TempInt1 = TempInt1 * TempInt2;
 TempDouble2 = (double)TempInt1;
 TempDouble1 = sqrt(TempDouble2);
 Seed = (unsigned int)TempDouble1;
 (**idispatch)(CLsprintf,TempStr, “The square root of %d is %.2g.”,
 TempInt1, TempDouble1);
 strcpy(*TempHdl, TempStr);
 paramPtr->returnValue = (Handle)TempHdl;


Community Search:
MacTech Search:

Software Updates via MacUpdate

Bookends 12.6.0 - Reference management a...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Access the power of Bookends directly from Mellel, Nisus Writer Pro, or MS Word (... Read more
Apple iBooks Author 2.4 - Create and pub...
Apple iBooks Author helps you create and publish amazing Multi-Touch books for iPad. Now anyone can create stunning iBooks textbooks, cookbooks, history books, picture books, and more for iPad. All... Read more
Web Snapper 3.3.9 - Capture entire Web p...
Web Snapper lets you capture Web pages exactly as they appear in your browser. You can send them to a file as images or vector-based, multi-page PDFs. It captures the whole Web page - eliminating the... Read more
Tunnelblick 3.6beta10 - GUI for OpenVPN...
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
EtreCheck 2.5.1 - For troubleshooting yo...
EtreCheck is a simple little app to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support... Read more
Paragraphs 1.0.4 - Writing tool just for...
Paragraphs is an app just for writers. It was built for one thing and one thing only: writing. It gives you everything you need to create brilliant prose and does away with the rest. Everything in... Read more
Things 2.8 - Elegant personal task manag...
Things is a task management solution that helps to organize your tasks in an elegant and intuitive way. Things combines powerful features with simplicity through the use of tags and its intelligent... Read more
Coda 2.5.12 - One-window Web development...
Coda is a powerful Web editor that puts everything in one place. An editor. Terminal. CSS. Files. With Coda 2, we went beyond expectations. With loads of new, much-requested features, a few surprises... Read more
PCalc 4.3 - Full-featured scientific cal...
PCalc is a full-featured, scriptable scientific calculator with support for hexadecimal, octal, and binary calculations, as well as an RPN mode, programmable functions, and an extensive set of unit... Read more
DiskMaker X 5.0 - Make a bootable OS X i...
DiskMaker X (was Lion DiskMaker) helps you to build a bootable drive from the official OS X installer app (the one you download from the Mac App Store). It detects the OS X Install program with... Read more

Camel Up (Games)
Camel Up 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: | Read more »
The Martian: Bring Him Home (Games)
The Martian: Bring Him Home 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Based on the best selling novel and critically acclaimed film, THE MARTIAN tells the story of Astronaut Mark... | Read more »
This Week at 148Apps: September 21-30, 2...
Leap Into Fall With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out above... | Read more »
Tweetbot 4 for Twitter (Social Networki...
Tweetbot 4 for Twitter 4.0 Device: iOS Universal Category: Social Networking Price: $4.99, Version: 4.0 (iTunes) Description: *** 50% off for a limited time. *** | Read more »
Mori (Games)
Mori 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Stop, rewind and unwind with Mori. Time is always running, take a moment to take control. Mori is an action puzzle game about infinitely... | Read more »
100 Years' War (Games)
100 Years' War 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »
Tower in the Sky (Games)
Tower in the Sky 0.0.60 Device: iOS Universal Category: Games Price: $1.99, Version: 0.0.60 (iTunes) Description: | Read more »
hocus. (Games)
hocus. 1.0.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0.0 (iTunes) Description: New, polished, mind-bending, minimal puzzle game with dozens of levels and extra-ordinary design Features:- Beautifully crafted... | Read more »
Mos Speedrun 2 (Games)
Mos Speedrun 2 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Mos is back, in her biggest and most exciting adventure ever! Wall-jump to victory through 30 mysterious, action packed levels... | Read more »
3D Touch could be a game-changer, but it...
Were you one of the lucky/financially secure enough ones to buy a new iPhone 6s or iPhone 6s Plus over the weekend? Yup, me too (I’m not convinced I was either of those two things, but let’s go with lucky for now), so I thought I’d delve into just... | Read more »

Price Scanner via

12-inch MacBooks in stock for up to $120 off,...
Adorama has 12″ Retina MacBooks in stock for up to $120 off MSRP including free shipping plus NY & NJ sales tax only. For a limited time, Adorama will include a free Apple USB-C to USB Adapter,... Read more
15-inch 2.2GHz Retina MacBook Pro on sale for... has the 15″ 2.2GHz Retina MacBook Pro on sale for $1799 including free shipping. Their price is $200 off MSRP, and it’s the lowest price available for this model (except for Apple’s $1699... Read more
iPhone 6s and 6s Plus Feature Improved Durabi...
Upgraded components in the new iPhone 6s Plus cost $16 more than the components in the earlier iPhone 6 Plus according to a preliminary estimate from IHS Inc. The bill of materials (BOM) for an... Read more
13-inch Retina MacBook Pros on sale for up to...
Adorama has 13″ Retina MacBook Pros on sale for up to $130 off MSRP. Shipping is free, and Adorama charges sales tax for NY & NJ residents only: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1199.99 $... Read more
Apple refurbished 2014 13-inch Retina MacBook...
Apple has Certified Refurbished 2014 13″ 2.6GHz/128GB SSD Retina MacBook Pros available $979, $320 off original MSRP. An Apple one-year warranty is included, and shipping is free: - 13″ 2.6GHz/128GB... Read more
iOS 9 Reflections Ten Days In – The ‘Book Mys...
I’ve never been much of an early adopter by philosophy or temperament, although I did buy the iPad Air 2 I’m typing this column on last fall only about a month after Apple unveiled it. However, my... Read more
Apple refurbished Time Capsules available for...
Apple has certified refurbished Time Capsules available for $120 off MSRP. Apple’s one-year warranty is included with each Time Capsule, and shipping is free: - 2TB Time Capsule: $179, $120 off - 3TB... Read more
OS X El Capitan Available as a Free Update To...
OS X El Capitan, the latest major release of Apple’s desktop operating system, is available today, September 30 as a free update for Mac users. “People love using their Macs, and one of the biggest... Read more
15-inch Retina MacBook Pros on sale for $150-...
B&H Photo has 2015 15″ Retina MacBook Pros on sale for up to $200 off MSRP including free shipping plus NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1815 $184 off - 15″ 2.5GHz Retina... Read more
Updated For iOS 9, InterConneX Lets You Store...
InterConneX version 1.2 is now a 64-bit app that’s completely compatible with iOS 9. InterConneX is a file storage, file management, and file sharing app for the iPhone or iPad that now takes... Read more

Jobs Board

*Apple* Systems Engineer (Mclean, VA and NYC...
Title: Apple Systems Engineer (Mclean, VA and NYC)Location: United States-New York-New York-NYC 200 Park Avenue (22005)Other Locations: United Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, you're Read more
*Apple* Retail - Multiple Customer Support P...
Job Description:Customer SupportSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the Read more
*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
SW QA Engineer - *Apple* TV - Apple (United...
**Job Summary** The Apple TV team is looking for experienced Quality Assurance Engineers with a passion for delivering first in class home entertainment solutions. **Key Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.