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]

 
AAPL
$101.63
Apple Inc.
-0.03
MSFT
$46.24
Microsoft Corpora
-0.46
GOOG
$573.10
Google Inc.
-2.52

MacTech Search:
Community Search:

Software Updates via MacUpdate

iFFmpeg 4.6.1 - Convert multimedia files...
iFFmpeg is a graphical front-end for FFmpeg, a command-line tool used to convert multimedia files between formats. The command line instructions can be very hard to master/understand, so iFFmpeg does... Read more
NTFS 11.3.62 - Provides full read and wr...
Paragon NTFS breaks down the barriers between Windows and OS X. Paragon NTFS effectively solves the communication problems between the Mac system and NTFS, providing full read and write access to... Read more
OS X Yosemite 10.10 DP8 - Developer Prev...
Note: This is a Developer Preview. You must be a registered Apple Mac Developer to download this update. You can also sign up for the free OS X Beta Program to download and preview public beta... Read more
FotoMagico 4.5 - Powerful slideshow crea...
FotoMagico lets you create professional slideshows from your photos and music with just a few, simple mouse clicks. It sports a very clean and intuitive yet powerful user interface. High image... Read more
Screenshot Path 1.2.1 - Change the defau...
Screenshot Path lets you change the folder where OS X saves screenshots. Screenshots are saved by default to the user’s desktop. This is handy for the occasional screenshot but those looking to take... Read more
Fantastical 1.3.16 - Create calendar eve...
Fantastical is the Mac calendar you'll actually enjoy using. Creating an event with Fantastical is quick, easy, and fun: Open Fantastical with a single click or keystroke Type in your event details... Read more
GIMP 2.8.14 - Powerful, free image editi...
GIMP is a multi-platform photo manipulation tool. GIMP is an acronym for GNU Image Manipulation Program. The GIMP is suitable for a variety of image manipulation tasks, including photo retouching,... Read more
HoudahSpot 3.9.3 - Advanced front-end fo...
HoudahSpot is an advanced file search tool built upon MacOS X Spotlight. Spotlight unleashed Create detailed queries to locate the exact file you need Narrow down searches. Zero in on files Save... Read more
djay 4.2.3 - Transform your Mac into a f...
djay transforms your Mac into a full-fledged DJ system, allowing you to mix your iTunes music library on a hyper-realistic turntable interface. Perform live, record mixes on-the-go, or enable... Read more
iDefrag 2.2.8 - Disk defragmentation and...
iDefrag helps defragment and optimize your disk for improved performance. Features include: Supports HFS and HFS+ (Mac OS Extended). Supports case sensitive and journaled filesystems. Supports... Read more

Latest Forum Discussions

See All

Vizzywig 4K (Photography)
Vizzywig 4K 1.0 Device: iOS iPhone Category: Photography Price: $999.99, Version: 1.0 (iTunes) Description: REQUIRES: iOS 7 on iPhone 5S with 32GB or 64GB. (Do not use iOS 8)The world's FIRST mobile 4K video capture, editing and... | Read more »
The Sleeping Prince Review
The Sleeping Prince Review By Jennifer Allen on September 15th, 2014 Our Rating: :: RESTRICTIVE KINGDOM SAVINGUniversal App - Designed for iPhone and iPad The Sleeping Prince looks and feels great to play, but its lack of peril and... | Read more »
It Came From Canada: Terra Battle
In some way or another, most Japanese RPGs owe something to Final Fantasy. But with Terra Battle, the now-common mix of Western medieval fantasy with Eastern anime aesthetic feels earned. After all, its developer, Mistwalker, was founded by the... | Read more »
Five Nights at Freddy’s Review
Five Nights at Freddy’s Review By Rob Thomas on September 15th, 2014 Our Rating: :: FIVE FRIGHTS AT FREDDY'SUniversal App - Designed for iPhone and iPad Can you survive five nights as the new night watchman of Freddy Fazbear’s... | Read more »
Phantom Rift Review
Phantom Rift Review By Nadia Oxford on September 15th, 2014 Our Rating: :: FRIENDLY PHANTOMUniversal App - Designed for iPhone and iPad Despite a snag here and there, Phantom Rift is a well-crafted and imaginative adventure RPG.   | Read more »
Phantom Rift – Tips, Tricks, Strategies,...
Hello, Wanderers: | Read more »
Meet the Newest Character for Temple Run...
Meet the Newest Character for Temple Run 2, from National Geographic Kids’ Action-Adventure Book Posted by Jessica Fisher on September 15th, 2014 [ | Read more »
Battle Riders Review
Battle Riders Review By Jordan Minor on September 15th, 2014 Our Rating: :: UNTWISTED METALUniversal App - Designed for iPhone and iPad BattleRiders has cool car combat, but it could be crazier.   | Read more »
Rapture - World Conquest (Games)
Rapture - World Conquest 1.0.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.0 (iTunes) Description: The End is coming! Bombard the globe with devastating miracles and decimate the enemy civilizations. Guide your... | Read more »
TRANSFORMERS: Age of Extinction Update A...
TRANSFORMERS: Age of Extinction Update Adds New Levels, a New Boss, and Special Events Posted by Jessica Fisher on September 15th, 2014 [ p | Read more »

Price Scanner via MacPrices.net

Free GIMP Professional Grade Graphics App Ver...
The latest 2.8.14 version of the oddly-named GIMP (acronym for: GNU Image Manipulation Program) open source, high-end image editing and creation alternative to Adobe’s Photoshop and refuge from... Read more
10% off iPhone 6 and 6 Plus Otterbox cases
Get 10% off on popular Otterbox iPhone 6 and iPhone 6 Plus cases at MacMall through September 19th. Use code OTTERBOX10 to see the discount. Read more
15-inch MacBook Pros on sale for up to $125 o...
Amazon has the new 2014 15″ Retina MacBook Pros on sale for up to $125 off MSRP including free shipping: - 15″ 2.2GHz Retina MacBook Pro: $1899.99 save $100 - 15″ 2.5GHz Retina MacBook Pro: $2374... Read more
27-inch 3.2GHz iMac on sale for $1698, $101 o...
Abt has the 27″ 3.2GHz iMac on sale for $1698 including free shipping. Their price is $101 off MSRP. Read more
More To Making A Larger iPad Than Expanded Sc...
CNET’s Ross Rubin has posted a thoughtful analysis of prospects for a larger display iPad Pro, noting that Microsoft and Samsung currently have the large-display touchscreen tablet category to... Read more
SwiftKey Keyboard Finally Coming To iPhone An...
At the TechCrunch Disrupt event in San Francisco, Swiftkey unveiled the first details about SwiftKey Keyboard for iPhone, iPad & iPod touch. SwiftKey’s philosophy is that you should be able to... Read more
Save $75 on the 16GB iPad mini with Retina Di...
Best Buy has the 16GB iPad mini with Retina Display on sale for $324.99 on their online store for a limited time. Their price is $75 off MSRP, and it’s the lowest price available for this mini.... Read more
21-inch 1.4GHz iMac on sale for $979, $120 of...
B&H Photo has the new 21″ 1.4GHz iMac on sale for $979.99 including free shipping plus NY sales tax only. Their price is $120 off MSRP. B&H will also include free copies of Parallels Desktop... Read more
Apple restocks refurbished 21-inch 1.4GHz iMa...
The Apple Store has restocked Apple Certified Refurbished 21″ 1.4GHz iMacs for $929 including free shipping plus Apple’s standard one-year warranty. Their price is $170 off the cost of new models,... Read more
13-inch 2.6GHz/256GB Retina MacBook Pro on sa...
Adorama has the 13″ 2.6GHz/256GB Retina MacBook Pro on sale for $1379 including free shipping plus NY & NJ sales tax only. Their price is $120 off MSRP, and it’s the lowest price available for... Read more

Jobs Board

*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...
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...
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.