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View Full Version : G5 OS to run in 32-bit 'bridge' mode



Aegis
07-08-2003, 01:33 AM
Good article at The Register here (http://www.theregister.co.uk/content/39/31600.html).

Beamtracer
07-08-2003, 03:07 AM
The Register article said:
When it runs 32-bit code, the 970 reconfigures the table it uses to map its 64-bit effective address space onto the 42-bit address space it can actually access to cope with 32-bit addresses. Two new instructions, which are part of the bridge spec., allow the first 16 entries of the table to point to any segment of memory within the effective address space. You got that? What were the main points again?

Well, Apple may have legal trouble if their system isn't really 64-bit. Maybe that's how Luxology managed to recompile its new 3D app to 64-bits in 15 minutes.

Beamtracer
07-11-2003, 09:07 PM
If anyone is interested in reading more technical data about whether Apple's upcoming Panther OS is a true 64-bit OS, there is a detailed account on the OSnews website:

http://www.osnews.com/story.php?news_id=4009

Ed M.
07-13-2003, 07:03 PM
OK guys ... you are worrying waaaaaaaaaaay too much here. :)

Beam, take a deep breath and read the initial post inquiring about 64bit posted by: Anunnaki here (http://arstechnica.infopop.net/OpenTopic/page?q=Y&a=tpc&s=50009562&f=8300945231&m=9080959175&p=4) .

Be sure to follow it through to the last page. Pay strict attention to the posts by: hobold (a friend of mine) Dragoth and MartainMatt. The G5 is as much 64bit as any other 64bit machine. Panther will accommodate any 64bit modifications developers want to make. Basic support for 64 bit is in Panther now. If developers want it and don't mind additional tweaks, they can access more than 4GB of memory in their apps. What is not in Panther at the moment is broad-spectrum (full) support for 64 bits across all (i.e., each and every) API that a developer can/might use without having to do anything special themselves. It can still be done though.

Developers can of course use the 64 bit ISA immediately for 64 bit integer operations by simply flipping a compiler switch. However, it's worth noting that apps written to use the 64 bit integer operations will not work on any 32 bit systems.

Now, the kicker is that unless it's a critical app for a particular market (i.e., like Lightwave, Maya etc.. is for 3D) I doubt developers will take advantage of this much because they usually write to be compatible with the machine at the low end of their target market. This is probably a 400 MHz G4 / 700 MHz G3. Of course it would be silly for NewTek and other high-end apps developers to target consumer-grade systems, So I don't think Mac Lightwavers have to worry. And if I remember correctly, the Lightwave crew assured us that their code is already 64bit ready. What's really sad however is that for some developers, its just now becoming expected that they get with the program and vectorize key functions and implement a higher degree of parallelism.

Does everyone feel better now? ;)

--
Ed

Jimzip
07-14-2003, 08:36 AM
I'll get back to you on that one..
Just have to rest brain.. For moment..



Jimzip:D