9 replies to this topic

[RhetoricalRuvim]

Is it possible to, on a 64-bit machine (with more than 4 GB memory), use the 32-bit mode and virtual memory, using the memory area above 4 GB for paging?
I mean, normally the hard drive would be used. But what if there is no hard drive but there is more memory beyond 4 GB. Would it be possible to access that memory from 32-bit protected mode? Or would I have to switch to 64-bit mode to access that and then switch back?

[dargueta]

Why not just use 64-bit mode with 32-bit instructions?

[RhetoricalRuvim]

Would it work with 32-bit programs?

[dargueta]

EDIT: Ignore what I just said. I need to look something up.

[RhetoricalRuvim]

So could I use paging and set all the tasks to 32-bit mode, except for the #PF handler and maybe some 64-bit tasks?

[dargueta]

Okay, you're reaching the limit of my knowledge here. I haven't done a whole ton of 64-bit programming in that specific area, but I'm pretty sure it'll work. Look into using "long mode."

[RhetoricalRuvim]

I have Intel Itanium manuals. Are Intel Itanium and Intel 64-bit the same things? Or would I have to order 64-bit manuals?

[dargueta]

Noooo. If you feed x86 code to an Itanium processor it'll start on fire and explode. You can get all of the I64 and IA-32 manuals from Intel's website.

[RhetoricalRuvim]

What are Itanium processors for? And are they newer than 64-bit?

[dargueta]

Itanium processors are 64-bit (so they're newer, yes) but they're specifically designed for servers and high-end computing. Its main feature is the ability to execute something like five or six instructions in one clock cycle, plus all sorts of pipelining and vector instructions.