Will x86 MMreg be replaced with XMMreg finally?
Will x86 MMreg be replaced with XMMreg finally?
and MMreg are mixed with FPreg
Re: Will x86 MMreg be replaced with XMMreg finally?
I'm not sure what you mean. If you want to use XMM registers, just go ahead.
Re: Will x86 MMreg be replaced with XMMreg finally?
I mean use XMM register set for SIMD only
Re: Will x86 MMreg be replaced with XMMreg finally?
Hi,
Do you mean using MMX registers for SIMD only, instead of having them aliased to FPU registers?
In this case, would you suggest removing the FPU completely (and having no non-SIMD floating point support at all), or would you add separate MMX registers so that you could use MMX and FPU at the same time (and so that context switching takes longer)? In this case (separate MMX and FPU registers), it'd be better to just use SSE instead of MMX if you also need the FPU...
Of course this assumes we're talking about general purpose CPUs. I'd like to see minimal CPUs for embedded systems (e.g. Atom without FPU, MMX or SSE); and I'd like to see "mixed core" (e.g. two full featured cores, plus 4 minimal "long mode only" cores without FPU, MMX or SSE in the same chip).
Cheers,
Brendan
The XMM registers are used for SIMD (SSE) only.blackoil wrote:I mean use XMM register set for SIMD only
Do you mean using MMX registers for SIMD only, instead of having them aliased to FPU registers?
In this case, would you suggest removing the FPU completely (and having no non-SIMD floating point support at all), or would you add separate MMX registers so that you could use MMX and FPU at the same time (and so that context switching takes longer)? In this case (separate MMX and FPU registers), it'd be better to just use SSE instead of MMX if you also need the FPU...
Of course this assumes we're talking about general purpose CPUs. I'd like to see minimal CPUs for embedded systems (e.g. Atom without FPU, MMX or SSE); and I'd like to see "mixed core" (e.g. two full featured cores, plus 4 minimal "long mode only" cores without FPU, MMX or SSE in the same chip).
Cheers,
Brendan
For all things; perfection is, and will always remain, impossible to achieve in practice. However; by striving for perfection we create things that are as perfect as practically possible. Let the pursuit of perfection be our guide.
Re: Will x86 MMreg be replaced with XMMreg finally?
Hi Brendan,
MMX and FP share the same registers set, and 80bit precison max.
In procedure with 2 slots operation, MMX or XMM is ok, but XMM is seperated set, doesn't need to transition between FP and MMX state. So I think MMX will be replaced with more dedicated XMM soon. And I like CELL/BE architecture, but it's not for common PC.
MMX and FP share the same registers set, and 80bit precison max.
In procedure with 2 slots operation, MMX or XMM is ok, but XMM is seperated set, doesn't need to transition between FP and MMX state. So I think MMX will be replaced with more dedicated XMM soon. And I like CELL/BE architecture, but it's not for common PC.
Re: Will x86 MMreg be replaced with XMMreg finally?
Define 'replaced'. Production software probably rarely uses MMX at all anymore, if ever. The CPU implementation only exists for backwards compatibility. So effectively SSE has already replaced MMX.