TweetFollow Us on Twitter

Mar 96 Tips
Volume Number:12
Issue Number:3
Column Tag:Tips & Tidbits

Tips & Tidbits

By Steve Sisak, Contributing Editor

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

Calling PowerPC Code
From 68K Code

There is a lot of information out there about calling 68K code from PowerPC code, but there is very little about calling PowerPC code from 68K code.

Here is a nice method for calling PowerPC code from 68K code. I am using CodeWarrior 7. This is a bit lengthy so hang in there:

There are three steps required to get things up and running. Let’s look at a sample scenario:

You have a 68K application that you just can’t convert to PowerPC code (I don’t know why you can’t convert it, but just bear with me), but you can take some of the time-critical code and convert it to a PowerPC shared library and call it from the 68K code.

Suppose you have two functions that perform data compression:

long  CompressData(  unsigned char *inBuffer, 
 unsigned char *outBuffer,
 unsigned long inBufferSize );
   
long  UncompressData(unsigned char *inBuffer, 
 unsigned char *outBuffer, 
 unsigned long inBufferSize );

Step 1 - Create a PPC shared library containing your functions.

We are going to export these functions using the #pragma export directive. This is set in the PPC Prefs area of Codewarrior preferences.

“the shared library”
// Prototypes

#pragma export on

#ifdef __cplusplus
extern "C" {
#endif

long  CompressData(  unsigned char *inBuffer, 
 unsigned char *outBuffer, 
 unsigned long inBufferSize );
   
long  UncompressData(   unsigned char *inBuffer,
 unsigned char *outBuffer,
 unsigned long inBufferSize );

#ifdef __cplusplus
}
#endif

#pragma export off
// CompressData

long  CompressData( unsigned char *inBuffer, unsigned char 
   *outBuffer, unsigned long inBufferSize )
{
    ... compress data code
}

// UncompressData
   
long  UncompressData( unsigned char *inBuffer, unsigned char 
     *outBuffer, unsigned long inBufferSize )
{
    ... uncompress data code
}

Set the project type to a shared library and build the project. We now have a PowerPC shared library that we will use in Step 2.


Step 2 - Create a resource-based PEF Fragment that references our shared library.

We create a header file that defines some mixed mode information.

“the header file”
#ifdef __cplusplus
extern "C" {
#endif

typedef long (*CompressDataProcPtr)( unsigned char *inBuffer, 
 unsigned char *outBuffer, unsigned long inBufferSize );
typedef long (*UncompressDataProcPtr)( unsigned char *inBuffer, 
 unsigned char *outBuffer, unsigned long inBufferSize);

#if GENERATINGCFM || USESROUTINEDESCRIPTORS

typedef UniversalProcPtr CompressDataUPP;
typedef UniversalProcPtr UncompressDataUPP;

enum {
 uppCompressDataProcInfo = kCStackBased
 | RESULT_SIZE( SIZE_CODE( sizeof( long ) ) )
 | STACK_ROUTINE_PARAMETER( 1, SIZE_CODE( 
 sizeof( unsigned char *) ) )
 | STACK_ROUTINE_PARAMETER( 2, SIZE_CODE( 
 sizeof( unsigned char *) ) ) | STACK_ROUTINE_PARAMETER( 3, SIZE_CODE( 

 sizeof( long ) ) )
};

enum {
 uppUncompressDataProcInfo = kCStackBased
 | RESULT_SIZE( SIZE_CODE( sizeof( long ) ) )
 | STACK_ROUTINE_PARAMETER( 1, SIZE_CODE( 
 sizeof( unsigned char *) ) )
 | STACK_ROUTINE_PARAMETER( 2, SIZE_CODE( 
 sizeof( unsigned char *) ) )
 | STACK_ROUTINE_PARAMETER( 3, SIZE_CODE( 
 sizeof( long ) ) )
};

#else

typedef CompressDataProcPtr CompressDataUPP;
typedef UncompressDataProcPtr UncompressDataUPP;
#endif

//============================================================
// Extern Globals
//

#ifndef powerc

extern CompressDataUPP    myCompressDataUPP;
extern UncompressDataUPP  myUncompressDataUPP;

#endif

//============================================================
// Macros
//

#if GENERATINGPOWERPC || defined(powerc) || defined (__powerc)

#define myCompressData( a, b, c )  CompressData( a, b, c )
#define myUncompressData( a, b, c )UncompressData( a, b, c )

#else

#define myCompressData( a, b, c ) \  
 (*(CompressDataUPP)myCompressDataUPP( a, b, c )
#define myUncompressData( a, b, c  ) \
 (*(CompressDataUPP)myUncompressDataUPP( a, b, c )

#endif

//============================================================
// Prototypes
//

long CompressData( unsigned char *inBuffer, unsigned char 
    *outBuffer, unsigned long inBufferSize );
long UncompressData( unsigned char *inBuffer, unsigned char 
  *outBuffer, unsigned long inBufferSize );

#ifdef __cplusplus
}
#endif

Now we define the source file:

“the source file”
#include "the header file"

#ifdef __cplusplus
extern "C" {
#endif

#if GENERATINGPOWERPC || defined(powerc) || defined (__powerc)
#pragma options align=mac68k
#endif

#ifdef __CFM68K__
#pragma lib_export on
#endif

RoutineDescriptorCompressDataRD = 
 BUILD_ROUTINE_DESCRIPTOR(  uppCompressDataProcInfo, 
 CompressData );

RoutineDescriptorUncompressDataRD = 
 BUILD_ROUTINE_DESCRIPTOR(  uppUncompressDataProcInfo, 
 UncompressData );


#ifdef __CFM68K__
#pragma lib_export off
#endif

#if GENERATINGPOWERPC || defined(powerc) || defined (__powerc)
#pragma options align=reset
#endif

#ifdef __cplusplus
}
#endif

Add the shared library we built in Step 1 to this project.

Set the project type to shared library and build the project. We now have a PowerPC shared library that we want to convert to a resource. (Note: we don’t export this as a PowerPC code resource with no header, since we would get link errors for an undefined main entry.)

Open the file up in a resource editor and create a new resource (I use a type of 'PEF ', but any will do). Move the PEF code from the data fork into this resource. (If your resource editor will not do this, then it is a simple matter of creating a small application that will do this for you; this excercise is left for the reader.)

We now have a resource file that we will add to our 68K project.


Step 3 - Add 68K support code to your project

Your 68K project needs to have a bit of support code to get the code resource and load it in as a code fragment. Add to your code:

#include "the header file"

We need to declare some globals for the universal procs that will store the address of the routine descriptors. Add to your code:

#ifndef powerc
CompressDataUPP  myCompressDataUPP;
UncompressDataUPPmyUncompressDataUPP;
#endif

The following function takes care of checking for the existence of the CFM and Mixed Mode managers. We pass it a pointer to a CFragConnectionID variable and a Handle variable, which we will use later on for clean up. Add to your code:

#ifndef powerc

// SetupPPCNativeCode

OSErr SetupPPCNativeCode( CFragConnectionID *connID, 
 Handle *PEFHandle,
   ResType codeFragmentType, 
 short codeFragmentID )
{
 OSErr  theErr = noErr;
 long   templong;
 Str255 failedFragName;
 

    // get PEF container resource from our resource fork
 
 *PEFHandle = ::Get1Resource( codeFragmentType, codeFragmentID );
 theErr = ::ResError();
 if( !(*PEFHandle) )
 {
 if( theErr )  
 return( theErr );
 else
 return( ::MemError() );
 }
 
    // Check for Mixed Mode Manager and Code Fragment Manager (CFM)
 
 Boolean  hasMixedMode = !Gestalt( gestaltMixedModeAttr, 
 &templong );
 Boolean  hasCFM = !Gestalt( gestaltCFMAttr, &templong );
 
 theErr = Gestalt( gestaltSysArchitecture, &templong );
 if( ( theErr ) || 
 ( templong == gestalt68k ) ||
 ( !hasCFM ) ||
 ( !hasMixedMode ) )
 {
 ::ReleaseResource( *PEFHandle );
 return( -1 );
 }
 
 DetachResource( *PEFHandle );
 MoveHHi( *PEFHandle );
 HLock( *PEFHandle );
 
    // Assume this is PowerPC code, so it must be “prepared”
 
 theErr = ::GetMemFragment( (Ptr)**PEFHandle, 0, 0,            
 kNewCFragCopy, connID, 0, failedFragName );
 if( theErr )
 {
 DisposeHandle( *PEFHandle );
 return( theErr );
 }

 CFragSymbolClassmyClass;
 
 if( !theErr )
 theErr = ::FindSymbol( *connID, 
    (ConstStr255Param)"\pCompressDataRD", 
    (Ptr*)&myCompressDataUPP, 
    &myClass );
 if( !theErr )
 theErr = ::FindSymbol( *connID, 
    (ConstStr255Param)"\pUncompressDataRD", 
    (Ptr*)&myUncompressDataUPP, 
    &myClass );

 if( theErr )
 {
 DisposeHandle( *PEFHandle );
 return( theErr );
 }
 
 return( noErr );
}

The following function takes the connection id and handle returned from SetupPPCNativeCode, frees the connection and disposes of the handle. Add to your code:

// TearDownPPCNativeCode

void TearDownPPCNativeCode( CFragConnectionID connID, Handle PEFHandle 
)
{
 ::CloseConnection( &connID );
 if( PEFHandle )
 ::DisposeHandle( PEFHandle );
}

#endif

Build your 68K project as you normally would and be sure to include the resource file we created in Step 2 and ensure the the shared library we created in Step 1 is either in the Extensions folder of the System Folder or in the same directory as the application.

Here is what you would do the call the PowerPC code from 68K:

long PowerPC_Compress( unsigned char *inBuffer, unsigned char 
    *outBuffer, unsigned long inBufferSize )
{
 #ifndef powerc
 
    // For efficiency you would probably put this call in initialization code.
    // sConnID and sPEFHandle are static globals.
 
 OSErr err = SetupPPCNativeCode( &sConnID, &sPEFHandle, 
 'PEF ', 128 );
 if( err )
 return( 0 );  // We couldn’t compress anything so return 0
 #endif
 
 long   result = 0;
 
 result = myCompressData( inBuffer, outBuffer, inBufferSize );
 
 #ifndef powerc
 
    // For efficiency you would probably put this call in termination code.
 
 TearDownPPCNativeCode( sConnID, sPEFHandle );
 #endif
}

long PowerPC_Uncompress( unsigned char *inBuffer, 
 unsigned char *outBuffer, unsigned long inBufferSize )
{
 #ifndef powerc
 
    // For efficiency you would probably put this call in initialization code.
    // sConnID and sPEFHandle are static globals.
 
 OSErr err = SetupPPCNativeCode( &sConnID, &sPEFHandle, 
 'PEF ', 128 );
 if( err )
 return( 0 );  // We couldn’t compress anything so return 0
 #endif
 
 long   result = 0;
 
 result = myUncompressData( inBuffer, outBuffer, inBufferSize );
 
 #ifndef powerc
 
    // For efficiency you would probably put this call in termination code.
 
 TearDownPPCNativeCode( sConnID, sPEFHandle );
 #endif
}


That’s all there is to it. Enjoy and happy coding.

- Chris Rudolph

[BuildRoutineDescriptor() doesn’t work right with CFM68k; use NewRoutineDescriptor() instead. BuildRoutineDescriptor() generates code so you need to call MakeDataExecutable() after it. - sgs]

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Things 2.5.4 - Elegant personal task man...
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
NeoOffice 2014.10 - Mac-tailored, OpenOf...
NeoOffice is a complete office suite for OS X. With NeoOffice, users can view, edit, and save OpenOffice documents, PDF files, and most Microsoft Word, Excel, and PowerPoint documents. NeoOffice 3.x... Read more
iPhoto Library Manager 4.2 - Manage mult...
iPhoto Library Manager allows you to organize your photos among multiple iPhoto libraries, rather than having to store all of your photos in one giant library. You can browse the photos in all your... Read more
Web Snapper 3.3.8 - 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
TeamViewer 10.0.41404 - Establish remote...
TeamViewer gives you remote control of any computer or Mac over the Internet within seconds, or can be used for online meetings. Find out why more than 200 million users trust TeamViewer! Free for... Read more
Ableton Live 9.1.8 - 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
VOX 2.5 - Music player that supports man...
VOX is a beautiful music player that supports many filetypes. The beauty is in its simplicity, yet behind the minimal exterior lies a powerful music player with a ton of features & support for... Read more
OmniFocus 2.1.2 - GTD task manager with...
OmniFocus helps you manage your tasks the way that you want, freeing you to focus your attention on the things that matter to you most. Capturing tasks and ideas is always a keyboard shortcut away in... Read more
Adobe Flash Player 17.0.0.169 - Plug-in...
Adobe Flash Player is a cross-platform, browser-based application runtime that provides uncompromised viewing of expressive applications, content, and videos across browsers and operating systems.... Read more
iMazing 1.1.3 - Complete iOS device mana...
iMazing (was DiskAid) is the ultimate iOS device manager with capabilities far beyond what iTunes offers. With iMazing and your iOS device (iPhone, iPad, or iPod), you can: Copy music to and from... Read more

Chainsaw Warrior: Lords of the Night has...
It's time to put the Darkness back in its place now that Chainsaw Warrior: Lords of the Night has officially made it to iOS. | Read more »
A World of Ice and Fire Lets You Stalk 2...
George R. R. Martin’s A World of Ice and Fire, by Random House, is a mobile guide to the epic series. The new update gives you the Journeys map feture that will let you track the movements of 25 different characters. But don't worry, you can protect... | Read more »
Gameloft Announces Battle Odyssey, a New...
Battle Odyssey, Gameloft's newest puzzle RPG, is coming to the App Store next week. Set in the world of Pondera, you will need to control the power of the elements to defend the world from evil. You'll be able to entlist over 500 allies to aid you... | Read more »
Fusion - HDR Camera (Photography)
Fusion - HDR Camera 1.0.0 Device: iOS Universal Category: Photography Price: $1.99, Version: 1.0.0 (iTunes) Description: Fusion creates HDR (high dynamic range) photos by capturing different exposures and then combining them into one... | Read more »
Sago Mini Toolbox (Education)
Sago Mini Toolbox 1.1 Device: iOS Universal Category: Education Price: $2.99, Version: 1.1 (iTunes) Description: Come build with the Sago Mini friends! Use a wrench, try a saw, or hammer some nails. From sewing hand puppets to... | Read more »
You Should Probably Grab Hitman GO While...
Hitman GO is a surprisingly cool (yet also incredibly drastic) departure from the Hitman series. It's well worth playing for any puzzle game fans out there, and at the moment you can get your hands - or garrotte if you will - on it for a mere $0.99... | Read more »
IFTTT is Bringing Do Button and Do Note...
IFTTT has announced Do Button and Do Note for the Apple Watch. Do Button lets you make your own personalized button that can connect to things like your Google Drive, control the temperature in your home with Nest Thermostat, or turn the lights on... | Read more »
How Many Days, Hours, and Minutes Are Le...
Countdown, by Yves Tscherry, is now available on the App Store. The app keeps track of countdowns to your favorite things such as someones birthday or days till the New Year. You can display the time in seconds, minutes, hours, days, weeks, months,... | Read more »
The All-New Misfit 2.0 App is Available...
Misfit has just given their app a complete overhaul. Misfit 2.0 now has a brand new interface with a sleek design and is easier to navigate. You'll be able to sync your Misfit device and look up health and fitness information faster than ever before... | Read more »
Halo: Spartan Strike (Games)
Halo: Spartan Strike 1.0 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0 (iTunes) Description: Delve into 30 challenging missions through cities and jungles using a devastating arsenal of weapons, abilities and... | Read more »

Price Scanner via MacPrices.net

Clearance 13-inch 2.6GHz Retina MacBook Pro a...
B&H Photo has clearance 2014 13″ 2.6GHz/128GB Retina MacBook Pros now available for $1099, or $200 off original MSRP. Shipping is free, and B&H charges NY sales tax only. Read more
Apple refurbished 2014 13-inch Retina MacBook...
The Apple Store has Apple Certified Refurbished 2014 13″ Retina MacBook Pros available for up to $400 off original MSRP, starting at $979. An Apple one-year warranty is included with each model, and... Read more
iMacs on sale for up to $205 off MSRP, NY tax...
B&H Photo has 21″ and 27″ iMacs on sale for up to $205 off MSRP including free shipping plus NY sales tax only: - 21″ 1.4GHz iMac: $1019 $80 off - 21″ 2.7GHz iMac: $1189 $110 off - 21″ 2.9GHz... Read more
Sale! 16GB iPhone 5S for $1 with service
Best Buy is offering 16GB iPhone 5Ss for $1.00 with 2-year activation at a participating cellular provider. Choose free home shipping and activation, or buy online and activate during in-store pickup... Read more
Apple refurbished 2014 MacBook Airs available...
The Apple Store has Apple Certified Refurbished 2014 MacBook Airs available starting at $679. An Apple one-year warranty is included with each MacBook, and shipping is free. These are currently the... Read more
27-inch 3.5GHz 5K iMac on sale for $2349, sav...
 Adorama has the 27″ 3.5GHz 5K iMac in stock today and on sale for $2349 including free shipping plus NY & NJ sales tax only. Their price is $150 off MSRP. For a limited time, Adorama will... Read more
Save up to $380 on an iMac with Apple refurbi...
The Apple Store has Apple Certified Refurbished iMacs available for up to $380 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $2119 $... Read more
iFixIt Teardown Awards 12-IInch Retina MacBoo...
iFixIt has posted its illustrated teardown of the new 12-inch MacBook Retina. They note that this new MacBook is less than half the thickness of the last Apple notebook called just “MacBook” back in... Read more
13-inch 2.5GHz MacBook Pro (refurbished) avai...
The Apple Store has Apple Certified Refurbished 13″ 2.5GHz MacBook Pros available for $829, or $270 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.... Read more
Faithful iPad 2 Gets A Second Career In Retir...
Finally, after four months’ transition, I handed my faithful old 2011 iPad 2 off to my wife at the end of March and switched whole-hog to using the iPad Air 2 I bought back in November. I’d found... 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
*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
*Apple* TV Live Streaming Frameworks Test En...
**Job Summary** Work and contribute towards the engineering of Apple 's state-of-the-art products involving video, audio, and graphics in Interactive Media Group (IMG) at Read more
Event Director, *Apple* Retail Marketing -...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global engagement strategy and team. Delivering an overarching brand 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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.