TweetFollow Us on Twitter

Oct 97 Factory Floor

Volume Number: 13 (1997)
Issue Number: 10
Column Tag: From The Factory Floor

A CodeWarrior Rhapsody Update: Part One

by Dave Mark, ©1997 by Metrowerks, Inc., all rights reserved.

Berardino E. Baratta is Vice President, Research and Development for Metrowerks Corp. With the Metrowerks R&D department quickly approaching 100, he has little time left for doing actual coding but he does still sneak it in (mostly by working on it late at night, or early in the morning, depending on how you look at it). Most recently having done compiler and linker modifications for PalmPilot Release 3. He also tries to spend as much time as possible with his wife and young son.

Andreas Hommel is currently the C/C++ front end and 68K back end/linker architect at Metrowerks. After finishing his masters degree in computer science, Andreas did some contract programming in the desktop publishing area and also published several games on the Macintosh and Amiga. He has been with Metrowerks for three and a half years.

Andreas lives in a small country village about 20 kilometers north of Hamburg, Germany with his wife, two Australian Shepherd dogs, and two arabian horses. When he is not coding, riding horses or walking his dogs Andreas likes travelling, playing a good video game, and driving really fast on the Autobahn. He also likes cooking and fine red wines (in particular Californian Cabernets).

Bob Campbell is the enginer responsible for the Mac OS and Rhapsody, PowerPC code generators. Prior to joining Metrowerks, he worked for Apple Computer for 8 years. To relieve the stress of programming he rides in bicycle races on the weekends.

Since starting at Metrowerks in early 1996, Lawrence You has been helping shape the CodeWarrior debugging architecture for non-Mac OS targets, including Rhapsody. He has been a longtime Macintosh developer, also working for Apple and Taligent.

As you read this column, the finishing touches are being applied, as CodeWarrior Pro 2 gets ready to ship. Hopefully, you've all had a chance to bang on the first Rhapsody pre-release and you're chomping at the bit to get your apps ported using Latitude and the first native-yellow box version of CodeWarrior. This month's interview is with the CodeWarrior Rhapsody team. It is the first half of a two parter. The second half will be featured in next month's issue.

Dave: What's the current state of Metrowerks' Rhapsody development tools?

Berardino Baratta: By the time you read this, CodeWarrior Professional Release 2 will have shipped. The Pro 2 release will show the fruit of our current labors (oh, the joys of printed publications and their built-in time delays).

We plan on having a release of our C/C++ PowerPC compiler with support for generating mixed C/C++/Objective-C binaries for native Yellow Box, which builds on the first pre-release version of Objective-C support that we shipped on Pro 1. We will also be shipping a pre-release version of both our IDE and Debugger hosted on Rhapsody as native Yellow Box applications. This port will be done using our Metrowerks Latitude porting library, which forces us to "eat our own dogfood", so to speak.

The new Apple OS architecture forced us to come up with a debug kernel solution that didn't involve MetroNub, as MetroNub was designed strictly for Mac OS and wouldn't port to Rhapsody. For that we ported a piece of technology that came out of the ashes of the Taligent project.

We've also modified our x86 code generator to emit Mach-O executables, so that when Apple releases their version of Yellow Box for x86, CodeWarrior users can target building binaries for that version without having to change toolsets.

Dave: What's the status of the Objective-C compiler?

Andreas Hommel: The basic Objective-C support is pretty much complete. We actually shipped a pre-release of our Objective-C front-end on the CodeWarrior Pro 1 CD (in Pre-Release:1.9b1 MacOS plugins.sit). This compiler comes with a mini runtime that lets you use Objective-C under Mac OS. Objective-C is actually a relative small extension to ANSI C (or C++) and a lot of the real advanced functionality, such as remote messaging, comes from NeXT's foundation framework. As you've seen in recent issues of MacTech, the OpenStep environment gives you a way to start learning the Objective-C syntax until Apple ships the first developer's release of Rhapsody.

Dave: What about support for modern Objective-C syntax?

Andreas Hommel: We still have to add support for the modern Objective-C syntax. The classic Objective-C syntax is based on Smalltalk and it looks a little weird to C/C++ or Java programmers. The modern syntax is much closer to C++ or Java. So, for example, instead of writing code like this:

@implementation MyClass : NSObject
{
     int m;
}

- (void)set:(int)i
{
     m=i;
}

- (void)print
{
     printf("m = %d\n",m);
}
@end

int main()
{
     MyClass *my;

     my=[[MyClass alloc] init];
     [my set:123];
     [my print];
     [my dealloc];

     return 0;
}

You will soon be able to write code like this:

@implementation MyClass : NSObject
{
     int m;
}

void set(int i)
{
     m=i;
}

void print()
{
     printf("m = %d\n",m);
}
@end

int main()
{
     MyClass *my;

     my=(new MyClass)->init();
     my->set(123);
     my->print();
     delete my;

     return 0;
}

The latter, modern form looks a lot more familiar to C++ programmers. We will support this as a real modern syntax specification falls into place.

Dave: What changes were required in the code generators to support Rhapsody?

Bob Campbell: As far as ABI changes go, Mach for PowerPC changes some of the runtime model from the Mac OS ABI. While the usage of registers when calling functions is almost exactly the same, the Mach model does not have a "TOC" pointer. This changes the way that global variables are addressed, as well as the way that routines in shared libraries are called.

There are a lot of reasons for the changes to the ABI. Unfortunately, it would probably take an entire article just to explain the underlying logic behind the current Mach-based ABI design. For now, I think it would be useful to see an overview. If we get the chance, we'll explore these issues in more detail in a future column.

Addressing global variables, in Mac OS addressing an external global variable requires an indirection via a TOC pointer, as follows:

    lwz r4,x(RTOC)
    lwz r4,0(r4)

In Mach (using the static model), this would be done by breaking the first instruction up into two. The first loads the high half of the address, which is then used as a base register with the low half of the address to load the actual data:

    lis r4,HA(L_x$non_lazy_ptr)
    lwz r4,LO(L_x$non_lazy_ptr)(r4)
    lwz r4,0(r4)

Note "HA" is the high 16 bits of the address adjusted for the case where the low 16 bits when treated as signed becomes a negative value. It is possible to use the HI function but in this cause it would require more instructions:

    lis r4,HI(L_x$non_lazy_ptr)
    ori r4,r4,LO(L_x$non_lazy_ptr)
    lwz r4,0(r4)
    lwz r4,0(r4)

When we are using the dynamic model we need to use a base register to insure position independant code so it becomes:

    ; set up PIC base register
    mflr  r0        ; save the return address
    bl    L_pic_base  ; put pc of next instruction in lr
      L_pic_base:
    mflr  r3        ; setup r3 as a base register
...
    addis r4,r3,HA(L_x$non_lazy_ptr-L_pic_base)
    lwz   r4,LO(L_x$non_lazy_ptr-L_pic_base)(r4)
    lwz   r4,0(r4)
...
    mtlr  r0        ; restore return address
    blr

Another example is of differences in calling external functions. In the Mac OS case, there may need to be a reload of the TOC pointer so it inserts a nop which the linker may fill with an instruction. In the Mach case, the reload of the TOC is not needed.

extern void x(void);

void y(void)
{
    x();
}

.y:
    mflr  r0
    stw   r0,0(r1)
    stwu  r1,-64(r1)
    bl    .x
    nop      ; slot for restoring the TOC pointer if needed
    lwz   r0,72(r1)
    addi  r1,r1,64
    mtlr  r0
    blr

becomes:

_y:
    mflr  r0
    stw   r0,0(r1)
    stwu  r1,-64(r1)
    bl    L_x$stub
    lwz   r0,72(r1)
    addi  r1,r1,64
    mtlr  r0
    blr

Dave: What about object formats?

Bob Campbell: The object format defined by Apple for Rhapsody is Mach-O. It is a very different from the object format that Metrowerks uses for Mac OS.

One big difference is that in our Mac OS object format we let our linker resolve things which the Mach-O object format requires be resolved at compile time. For example, in our current object files we start the address for each function at zero and let the linker resolve the addresses. For Mach-O we must assign each function and variable a unique address before the object file is written.

I would like to point out that these are the ABIs and Object Formats that are being used for the initial release of Rhapsody. Once the initial version is out the door we will start looking for ways to improve the performance of the dynamic model.

Dave: What's the linker strategy for Mach-O?

Berardino Baratta: For this part of the equation, we decided early on, after discussions with core Apple/NeXT engineers, that NeXT had developed some very good linker technology, and it made the most sense to license that technology so we could convert that command line linker into a CodeWarrior plugin for use under our IDE. This allows us to concentrate our resources on the rest of our tools and not in trying to replicate the excellent linker optimizations that the NeXT linker implements. This helps reduce the method call overhead penalty that the ObjectiveC runtime imposes.

Dave: What can you tell me about porting the IDE to Rhapsody?

Berardino Baratta: Technically, we don't have to do anything to port our IDE to Rhapsody as it will run just fine inside of the Blue Box (Apple's solution that allow users to run their existing application inside of Rhapsody). Of course, that would be too easy. So, as I said before, we're using Latitude to solve this part of the equation. This solution involved a two step process.

First, we ported our IDE to run under Latitude hosted on SunOS, as at the time Latitude for Rhapsody was still under development. This cleaned up any issues in the IDE that were not supported under Latitude, and validated the core of Latitude with another large sourcebase.

Next, we rebuilt the IDE under Latitude for Rhapsody, giving David Hempling and the other Latitude engineers a large sourcebase with which to validate their port of Latitude for Rhapsody. If all went well, then you should be seeing the results of this work on Pro 2, as a pre-release version of the Metrowerks IDE running native on Rhapsody in the Yellow Box.

In the future, we're going to use the native hooks in Latitude to add in Yellow Box specific functionality that will make sure that the IDE is, from the user's standpoint, a fully native Yellow Box application.

Dave: Will there be any integration between CodeWarrior and InterfaceBuilder?

Berardino Baratta: Yes, we're working together with Apple to fully support InterfaceBuilder (IB), but this work is not scheduled to begin until after our IDE is up and stable under Rhapsody. Our goal is to replace ProjectBuilder, in order to provide seamless support between IB and the Metrowerks IDE.

Next month, we'll finish up this interview, starting with Lawrence You's discussion of yellow box debugging plans.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Latest Forum Discussions

See All

Whitethorn Games combines two completely...
If you have ever gone fishing then you know that it is a lesson in patience, sitting around waiting for a bite that may never come. Well, that's because you have been doing it wrong, since as Whitehorn Games now demonstrates in new release Skate... | Read more »
Call of Duty Warzone is a Waiting Simula...
It's always fun when a splashy multiplayer game comes to mobile because they are few and far between, so I was excited to see the notification about Call of Duty: Warzone Mobile (finally) launching last week and wanted to try it out. As someone who... | Read more »
Albion Online introduces some massive ne...
Sandbox Interactive has announced an upcoming update to its flagship MMORPG Albion Online, containing massive updates to its existing guild Vs guild systems. Someone clearly rewatched the Helms Deep battle in Lord of the Rings and spent the next... | Read more »
Chucklefish announces launch date of the...
Chucklefish, the indie London-based team we probably all know from developing Terraria or their stint publishing Stardew Valley, has revealed the mobile release date for roguelike deck-builder Wildfrost. Developed by Gaziter and Deadpan Games, the... | Read more »
Netmarble opens pre-registration for act...
It has been close to three years since Netmarble announced they would be adapting the smash series Solo Leveling into a video game, and at last, they have announced the opening of pre-orders for Solo Leveling: Arise. [Read more] | Read more »
PUBG Mobile celebrates sixth anniversary...
For the past six years, PUBG Mobile has been one of the most popular shooters you can play in the palm of your hand, and Krafton is celebrating this milestone and many years of ups by teaming up with hit music man JVKE to create a special song for... | Read more »
ASTRA: Knights of Veda refuse to pump th...
In perhaps the most recent example of being incredibly eager, ASTRA: Knights of Veda has dropped its second collaboration with South Korean boyband Seventeen, named so as it consists of exactly thirteen members and a video collaboration with Lee... | Read more »
Collect all your cats and caterpillars a...
If you are growing tired of trying to build a town with your phone by using it as a tiny, ineffectual shover then fear no longer, as Independent Arts Software has announced the upcoming release of Construction Simulator 4, from the critically... | Read more »
Backbone complete its lineup of 2nd Gene...
With all the ports of big AAA games that have been coming to mobile, it is becoming more convenient than ever to own a good controller, and to help with this Backbone has announced the completion of their 2nd generation product lineup with their... | Read more »
Zenless Zone Zero opens entries for its...
miHoYo, aka HoYoverse, has become such a big name in mobile gaming that it's hard to believe that arguably their flagship title, Genshin Impact, is only three and a half years old. Now, they continue the road to the next title in their world, with... | Read more »

Price Scanner via MacPrices.net

B&H has Apple’s 13-inch M2 MacBook Airs o...
B&H Photo has 13″ MacBook Airs with M2 CPUs and 256GB of storage in stock and on sale for up to $150 off Apple’s new MSRP, starting at only $849. Free 1-2 day delivery is available to most US... Read more
M2 Mac minis on sale for $100-$200 off MSRP,...
B&H Photo has Apple’s M2-powered Mac minis back in stock and on sale today for $100-$200 off MSRP. Free 1-2 day shipping is available for most US addresses: – Mac mini M2/256GB SSD: $499, save $... Read more
Mac Studios with M2 Max and M2 Ultra CPUs on...
B&H Photo has standard-configuration Mac Studios with Apple’s M2 Max & Ultra CPUs in stock today and on Easter sale for $200 off MSRP. Their prices are the lowest available for these models... Read more
Deal Alert! B&H Photo has Apple’s 14-inch...
B&H Photo has new Gray and Black 14″ M3, M3 Pro, and M3 Max MacBook Pros on sale for $200-$300 off MSRP, starting at only $1399. B&H offers free 1-2 day delivery to most US addresses: – 14″ 8... Read more
Department Of Justice Sets Sights On Apple In...
NEWS – The ball has finally dropped on the big Apple. The ball (metaphorically speaking) — an antitrust lawsuit filed in the U.S. on March 21 by the Department of Justice (DOJ) — came down following... Read more
New 13-inch M3 MacBook Air on sale for $999,...
Amazon has Apple’s new 13″ M3 MacBook Air on sale for $100 off MSRP for the first time, now just $999 shipped. Shipping is free: – 13″ MacBook Air (8GB RAM/256GB SSD/Space Gray): $999 $100 off MSRP... Read more
Amazon has Apple’s 9th-generation WiFi iPads...
Amazon has Apple’s 9th generation 10.2″ WiFi iPads on sale for $80-$100 off MSRP, starting only $249. Their prices are the lowest available for new iPads anywhere: – 10″ 64GB WiFi iPad (Space Gray or... Read more
Discounted 14-inch M3 MacBook Pros with 16GB...
Apple retailer Expercom has 14″ MacBook Pros with M3 CPUs and 16GB of standard memory discounted by up to $120 off Apple’s MSRP: – 14″ M3 MacBook Pro (16GB RAM/256GB SSD): $1691.06 $108 off MSRP – 14... Read more
Clearance 15-inch M2 MacBook Airs on sale for...
B&H Photo has Apple’s 15″ MacBook Airs with M2 CPUs (8GB RAM/256GB SSD) in stock today and on clearance sale for $999 in all four colors. Free 1-2 delivery is available to most US addresses.... Read more
Clearance 13-inch M1 MacBook Airs drop to onl...
B&H has Apple’s base 13″ M1 MacBook Air (Space Gray, Silver, & Gold) in stock and on clearance sale today for $300 off MSRP, only $699. Free 1-2 day shipping is available to most addresses in... Read more

Jobs Board

Senior Product Associate - *Apple* Pay (AME...
…is seeking a Senior Associate of Digital Product Management to support our Apple Pay product team. Labs drives innovation at American Express by originating, Read more
Medical Assistant - Surgical Oncology- *Apple...
Medical Assistant - Surgical Oncology- Apple Hill Location: WellSpan Medical Group, York, PA Schedule: Full Time Sign-On Bonus Eligible Remote/Hybrid Regular Apply Read more
Omnichannel Associate - *Apple* Blossom Mal...
Omnichannel Associate - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) - Apple Read more
Cashier - *Apple* Blossom Mall - JCPenney (...
Cashier - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) - Apple Blossom Mall Read more
Operations Associate - *Apple* Blossom Mall...
Operations Associate - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) - Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.