[geeks] Carly's Gone!!!
Francisco Javier Mesa-Martinez
lefa at ucsc.edu
Thu Feb 10 20:26:16 CST 2005
On Thu, 10 Feb 2005, Charles Shannon Hendrix wrote:
> Not quite related, but I read a paper that said that AMD basically has
> created their own very powerful CPU, and the Intel ISA is actually a
> hardware emulation on top of that.
Actually the X86 machines since the Pentium have been that way, the CISC
x86 ops are converted into micro-ops that are executed by a risc-like
core, think of it of RISC microcode if you will. You could execute those
microops natively, but why bother... since CISC gives you the nice benefit
of reduced instruction bandwidth. AMD got that technology from NexGen....
> It seems to me that AMD could release their own CPU by removing that
> layer without a tremendous engineering effort.
No point in doing that really, afterall they lose the whole x86 software
library which is the only reason why they sell processors. The 29x00
series was their native RISC stuff, but I dunno if they still produce it.
> Is this the same HyperTransport that VIA and AMD are using on the AMD64
Theoretically HyperTransport was an industry standard so I dunno if Alpha
was the originator of the technology.
> For example, my motherboard has one HyperTransport link between CPU and
> the northbridge, 16-bits at N GHz (can't remember right this moment), so
> it can move quite a bit of data.
> I read a spec sheet and it said that HyperTransport can be 8-16 bits
> wide, and listed several operating speeds, with more coming in the
> Also in the future:
> - links for more than just CPU and northbridge
> - a cross-bar like system to connect components with HT
> - other goodies I can't remember
> If this actually pans out, maybe the PC will finally get some rational
> I/O on the motherboard.
Well that is theoretically what PCI-Express is supposed to achive, is a
switched connection fabric between CPU/Chipset/Memory/IO, pretty neat
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