[MageX]

Actually, davilla just needs to learn how the CPU actually works. The 64-bit registers are simply not available in 32-bit mode. Thus, a 32-bit app is *not* using 64-bit registers, but can certainly use 64-bit (and larger) variables in RAM.

http://en.wikipedia.org/wiki/X86#64-bit

Edit: The SIMD registers are not specific to CPU mode, as far as I know. So, assuming SIMD is enabled, those instructions will have the larger registers. But, I already commented on SIMD use.

[davilla]

You are not paying attention and getting lost in forest of register details. It does NOT matter that much. Maybe a 1-5 percent difference depending on what you are doing in XBMC. 64 bit only matters if you have to churn through a very large chunk of memory and there are better ways to do this but they require a bit more coding that just using the address pointer and ++'ing it. That's the problem with most programmers, they get stuck in the details and forget the purpose.

We have this discussion about one every year, some person comes in brimming with new found knowledge about 32 vs 64 bit. Proclaims that we are silly in using 32 bit and 64 bit will give us N times the performance by quoting this or that. Well, surprise, it just does not matter that much and the only thing 64 bit does is increase the size of our e-penis.

I added 64 bit builds to OSX platform for the ability to run a pure 64 bit kernel and 64 bit app under the newer Darwin versions. It had nothing to do with performance.

I'm 54, I cut my teeth on self build 8080A systems in the early 80s programming them by hand in octal to collect data for physics experiments. This was the pre-personal computer days when the only thing anyone could afford was chips so you got them and wired them up yourself. I've done them all, micros, minis, mainframes. I even still have my original KayPro II modified to work with 8" disks. Every now and then, I crank it up and play with WordStar. I do hardware, firmware, and software but draw the line at wetware.

PS. SSE is always enabled for OSX Intel, SSE3 in fact. Apple never sold Intel notebook/desktop hardware with a non-SSE3 capable CPU. In fact, an SSE3 emulator was written by Turbo for the original AppleTV which used a Pentium-M which only has SSE2. This emulator enabled quicktime and desktop OSX to run on the 1st gen AppleTV.

[MageX]

Seriously? All SIMD instructions are always on. SIMD of any version is not auto-magically used by programs. It has to be specifically enabled in your compiler or coded into your assembly. Otherwise, your program simply will not use SIMD instructions.

Your "I'm older, so I know more" attempt isn't fact, it's opinion. I wasn't saying that 64-bit should be used. If anything, I was saying that 64-bit compilation was pointless if your information was fact. As for having it for purity of the environment, that's fairly reasonable, but doesn't change the fact that what you have said wasn't 100% correct.

A question was asked as to the difference between 32-bit and 64-bit, and you gave an incomplete answer. Period. You then further claimed that in 32-bit apps, the 64-bit registers were in use. That is simply not true. For the 64-bit GPRs, you have to be in 64-bit mode (aka 64-bit app). I never claimed you couldn't program. I never said I was a better programmer than you. However, I obviously have some knowledge that you either didn't know or refuse to accept as fact.

Again, SSE is not "enabled" by or for OSX. OSX uses SSE by design. With 6 versions of SSE available, I'll assume that you are claiming to have SSE3 (the minimum needed for OSX, as you pointed out) enabled for all OSX compiles of XBMC. That still doesn't enable 64-bit registers for a 32-bit app, though.

[Memphiz]

What is wetware?

[Martijn]

* Martijn wants 256bit

[davilla]

This thread has gone past the point of being useful, closing it. Take that 64-bit bone and chew on it elsewhere.