TweetFollow Us on Twitter

XCMD ANSI Library
Volume Number:6
Issue Number:6
Column Tag:Programmer's Forum

XCMD ANSI Library

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.

XCMD ANSI Library

[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 */

LOADCODELIB()
if (!initCodeLib())
 return;
else
 HLock(dispatch);
if (!initFCodeLib())
 HUnlock(dispatch);
 return;
else
 HLock(ddispatch);

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 */

initCodeLib()
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.

CodeLibDispatch.c

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 */

funcTable[CLdispatchErr]=dispatchErr;
funcTable[CLatoi]=(Function)atoi;
funcTable[CLatol]=(Function)atol;
funcTable[CLsprintf]=(Function)sprintf;
funcTable[CLsrand]=(Function)srand;
funcTable[CLstrcpy]=(Function)strcpy;

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.

General

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 @ cc.utah.edu.

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

CODELIB;

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.

LOADCODELIB();

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.

UNLOADCODELIB();

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
 {
 CLdispatchErr=0,
 CLatoi,
 CLatol,
 CLsprintf,
 CLsrand,
 CLstrcpy,
 CLsqrt=1 /*Double/struct lib */
 } CodeLib;

#define ROUTINES 5
#define FROUTINES  1

#ifndef NOCODELIBDEF
#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 
*)(s2))))
#define sqrt(d) ((**ddispatch)(CLsqrt, (double)(d)))
#endif NOCODELIBDEF

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)))))))
#else
#define initcodeLib() 1
#endif CODELIB

#ifndef NOFLOATLIB
#define initFCodeLib() (ddispatch=(Dfunch)GetResource(‘LIB ‘, 18001))
#else
#define initFCodeLib() 1
#endif NOFLOATLIB

#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;
#endif
Listing:  CodeLibDispatch.c

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

#define NOCODELIBDEF
#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;
 };
 funcTable[CLdispatchErr]=dispatchErr;
 funcTable[CLatoi]=(Function)atoi;
 funcTable[CLatol]=(Function)atol;
 funcTable[CLsprintf]=(Function)sprintf;
 funcTable[CLsrand]=(Function)srand;
 funcTable[CLstrcpy]=(Function)strcpy;
 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  */
 }
 UnloadA4Seg(0L);
 } /* Main*/

void dispatchErr(void)
 {
 SysBeep(5);
 }
Listing:  FCodeLibDispatch.c

#include <math.h>

#define NOCODELIBDEF
#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;
 };
 funcTable[CLdispatchErr]=dispatchErr;
 funcTable[CLsqrt]=(Function)sqrt;
 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  */
 }
 UnloadA4Seg(0L);
 } /* Main*/

void dispatchErr(void)
 {
 SysBeep(5);
 }

Listing: testCodeLib.c

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

CODELIB;

pascal void main(XCmdBlockPtr paramPtr)
{
 int    TempInt1, TempInt2;
 unsigned int  Seed;
 long   TempLong;
 StringHandle  TempHdl;
 double TempDouble1, TempDouble2;
 Ptr    TempPtr;
 Str255 TempStr;
 
 RememberA0();
 SetUpA4();
 LOADCODELIB();
 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;
 srand(Seed);
 (**idispatch)(CLsprintf,TempStr, “The square root of %d is %.2g.”,
 TempInt1, TempDouble1);
 strcpy(*TempHdl, TempStr);
 paramPtr->returnValue = (Handle)TempHdl;
 
 UNLOADCODELIB();
 RestoreA4();
}

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Latest Forum Discussions

See All

Six fantastic ways to spend National Vid...
As if anyone needed an excuse to play games today, I am about to give you one: it is National Video Games Day. A day for us to play games, like we no doubt do every day. Let’s not look a gift horse in the mouth. Instead, feast your eyes on this... | Read more »
Old School RuneScape players turn out in...
The sheer leap in technological advancements in our lifetime has been mind-blowing. We went from Commodore 64s to VR glasses in what feels like a heartbeat, but more importantly, the internet. It can be a dark mess, but it also brought hundreds of... | Read more »
Today's Best 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 below... | Read more »
Nintendo and The Pokémon Company's...
Unless you have been living under a rock, you know that Nintendo has been locked in an epic battle with Pocketpair, creator of the obvious Pokémon rip-off Palworld. Nintendo often resorts to legal retaliation at the drop of a hat, but it seems this... | Read more »
Apple exclusive mobile games don’t make...
If you are a gamer on phones, no doubt you have been as distressed as I am on one huge sticking point: exclusivity. For years, Xbox and PlayStation have done battle, and before this was the Sega Genesis and the Nintendo NES. On console, it makes... | Read more »
Regionally exclusive events make no sens...
Last week, over on our sister site AppSpy, I babbled excitedly about the Pokémon GO Safari Days event. You can get nine Eevees with an explorer hat per day. Or, can you? Specifically, you, reader. Do you have the time or funds to possibly fly for... | Read more »
As Jon Bellamy defends his choice to can...
Back in March, Jagex announced the appointment of a new CEO, Jon Bellamy. Mr Bellamy then decided to almost immediately paint a huge target on his back by cancelling the Runescapes Pride event. This led to widespread condemnation about his perceived... | Read more »
Marvel Contest of Champions adds two mor...
When I saw the latest two Marvel Contest of Champions characters, I scoffed. Mr Knight and Silver Samurai, thought I, they are running out of good choices. Then I realised no, I was being far too cynical. This is one of the things that games do best... | Read more »
Grass is green, and water is wet: Pokémo...
It must be a day that ends in Y, because Pokémon Trading Card Game Pocket has kicked off its Zoroark Drop Event. Here you can get a promo version of another card, and look forward to the next Wonder Pick Event and the next Mass Outbreak that will be... | Read more »
Enter the Gungeon review
It took me a minute to get around to reviewing this game for a couple of very good reasons. The first is that Enter the Gungeon's style of roguelike bullet-hell action is teetering on the edge of being straight-up malicious, which made getting... | Read more »

Price Scanner via MacPrices.net

Take $150 off every Apple 11-inch M3 iPad Air
Amazon is offering a $150 discount on 11-inch M3 WiFi iPad Airs right now. Shipping is free: – 11″ 128GB M3 WiFi iPad Air: $449, $150 off – 11″ 256GB M3 WiFi iPad Air: $549, $150 off – 11″ 512GB M3... Read more
Apple iPad minis back on sale for $100 off MS...
Amazon is offering $100 discounts (up to 20% off) on Apple’s newest 2024 WiFi iPad minis, each with free shipping. These are the lowest prices available for new minis among the Apple retailers we... Read more
Apple’s 16-inch M4 Max MacBook Pros are on sa...
Amazon has 16-inch M4 Max MacBook Pros (Silver and Black colors) on sale for up to $410 off Apple’s MSRP right now. Shipping is free. Be sure to select Amazon as the seller, rather than a third-party... Read more
Red Pocket Mobile is offering a $150 rebate o...
Red Pocket Mobile has new Apple iPhone 17’s on sale for $150 off MSRP when you switch and open up a new line of service. Red Pocket Mobile is a nationwide MVNO using all the major wireless carrier... Read more
Switch to Verizon, and get any iPhone 16 for...
With yesterday’s introduction of the new iPhone 17 models, Verizon responded by running “on us” promos across much of the iPhone 16 lineup: iPhone 16 and 16 Plus show as $0/mo for 36 months with bill... Read more
Here is a summary of the new features in Appl...
Apple’s September 2025 event introduced major updates across its most popular product lines, focusing on health, performance, and design breakthroughs. The AirPods Pro 3 now feature best-in-class... Read more
Apple’s Smartphone Lineup Could Use A Touch o...
COMMENTARY – Whatever happened to the old adage, “less is more”? Apple’s smartphone lineup. — which is due for its annual refresh either this month or next (possibly at an Apple Event on September 9... Read more
Take $50 off every 11th-generation A16 WiFi i...
Amazon has Apple’s 11th-generation A16 WiFi iPads in stock on sale for $50 off MSRP right now. Shipping is free: – 11″ 11th-generation 128GB WiFi iPads: $299 $50 off MSRP – 11″ 11th-generation 256GB... Read more
Sunday Sale: 14-inch M4 MacBook Pros for up t...
Don’t pay full price! Amazon has Apple’s 14-inch M4 MacBook Pros (Silver and Black colors) on sale for up to $220 off MSRP right now. Shipping is free. Be sure to select Amazon as the seller, rather... Read more
Mac mini with M4 Pro CPU back on sale for $12...
B&H Photo has Apple’s Mac mini with the M4 Pro CPU back on sale for $1259, $140 off MSRP. B&H offers free 1-2 day shipping to most US addresses: – Mac mini M4 Pro CPU (24GB/512GB): $1259, $... Read more

Jobs Board

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