Gentoo Archives: gentoo-dev

From: R Hill <deemkay@×××××.com>
To: gentoo-dev@××××××××××××.org
Subject: [gentoo-dev] Re: MPlayer cpu USE flags zaniness
Date: Sun, 27 Mar 2005 12:40:55
Message-Id: d26929$ptn$
In Reply to: Re: [gentoo-dev] MPlayer cpu USE flags zaniness by Michael Marineau
1 Michael Marineau wrote:
2 > Chris White wrote:
3 >>Michael Marineau wrote:
4 >>
5 >>>What's the point of a use flag if you purposfully use the sse useflag to
6 >>>do something different? this sort of thing would make more sense:
7 >>>
8 >>>sse = sse's integer logic
9 >>>sse = sse's floating point stuff
10 >>>mmx2 = mmx2
11 >>
12 >>
13 >>Problem mmx2 = sse (on intel)
14 >>mmx2 = I don't know what (on amd)
15 >>mmx2 != mmxext
16 >
17 > Weird, so where does this mmx2 name come from then if it's just sse?
19 Hey. I'm the complaining users. ;]
21 This has been bugging me so I've been doing some digging, trying to put
22 together some kind of idea of how everything fits. I hope it helps make
23 some sense. Basically, you can see what i came up with in this post.
27 I'm a little hazy about the AMD side of it, as I've no experience with
28 them. What I do know for sure is that back in '99, Intel was hyping the
29 new KNI (Katmai New Instructions) instruction set, aka Pentium III. You
30 can see references to it in articles around that time (see forum post).
31 Up until the the actual release of the Katmai these articles often use
32 KNI and MMX2 interchangably. The best source I can find that I trust
33 not to be PR fluff is - where
34 it's stated "The official name for Katmai is Pentium III, what the new
35 opcodes are called is still in the air, is it MMX2, KNI or perhaps
36 XMM?". The name that Intel did finally settle on was Streaming SIMD
37 Extensions - SSE. So, for all intents and purposes MMX2 = SSE.
39 Now AMD had the 3DNow! instruction set which they introduced with the
40 K6-2 in '98, as a SIMD extension to MMX. SSE/MMX2 was brought in after
41 that by Intel. So MMX2 != AMD and never did. AMD did later integrate
42 SSE into the 3DNow Pro though. So what the hell is MMXExt? I think
43 it's an old name for the original integer instructions extensions the
44 3DNow made to MMX. That's a very sketchy conclusion though and I
45 wouldn't be surprised to be proven wrong. I can say for certain that it
46 is AMD specific. If you want proof:
47 ;]
49 As to how to apply all this to MPlayer..
51 o.O
54 obl refs-
62 r.
64 --
65 gentoo-dev@g.o mailing list