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The Intel architecture manufacturers privilege reverse compatibility, so I am not sure if there's a limit where it would be good to sacrifice some of that compa

The Intel architecture manufacturers privilege reverse compatibility, so I am not sure if there's a limit where it would be good to sacrifice some of that compatibility in exchange for performance or simplicity. I mean, for example I have not seen a single person talking about how to integrate AMD's 3DNow! in their software. Mostly because AMD adopted SSE, but Intel didn't adopt 3DNow!, so people use SSE... as a simple example. So you end up with a vestigial set of unused instructions... with the associated cost, since it's not for free in terms of design, implementation, manufacturing, etc.

wolfgke 9y ago
> I mean, for example I have not seen a single person talking about how to integrate AMD's 3DNow! in their software. Mostly because AMD adopted SSE, but Intel didn't adopt 3DNow!, so people use SSE... as a simple example. So you end up with a vestigial set of unused instructions... with the associated cost, since it's not for free in terms of design, implementation, manufacturing, etc. Because of this reason AMD decided to drop support for 3DNow! in more recent processors: > https://en.wikipedia.org/w/index.php?title=3DNow!&oldid=769683777 https://en.wikipedia.org/w/index.php?title=3DNow!&oldid=7696... "However, the instruction set never gained much popularity, and AMD announced on August 2010 that support for 3DNow would be dropped in future AMD processors, except for two instructions (the PREFETCH and PREFETCHW instructions). The two instructions are also available in Bay-Trail Intel processors.". Also look under "Processors supporting 3DNow" (emphasis mine): "All AMD processors after K6-2 based on K6, Athlon, Athlon 64 and Phenom architecture families. Not supported in Bulldozer, Bobcat and Zen architecture processors and their derivates."
- partycoder 9y ago
  I see!, thanks for pointing out this about 3dNow!.

wolfgke 9y ago

> I mean, for example I have not seen a single person talking about how to integrate AMD's 3DNow! in their software. Mostly because AMD adopted SSE, but Intel didn't adopt 3DNow!, so people use SSE... as a simple example. So you end up with a vestigial set of unused instructions... with the associated cost, since it's not for free in terms of design, implementation, manufacturing, etc. Because of this reason AMD decided to drop support for 3DNow! in more recent processors: > https://en.wikipedia.org/w/index.php?title=3DNow!&oldid=769683777 https://en.wikipedia.org/w/index.php?title=3DNow!&oldid=7696... "However, the instruction set never gained much popularity, and AMD announced on August 2010 that support for 3DNow would be dropped in future AMD processors, except for two instructions (the PREFETCH and PREFETCHW instructions). The two instructions are also available in Bay-Trail Intel processors.". Also look under "Processors supporting 3DNow" (emphasis mine): "All AMD processors after K6-2 based on K6, Athlon, Athlon 64 and Phenom architecture families. Not supported in Bulldozer, Bobcat and Zen architecture processors and their derivates."

partycoder 9y ago
I see!, thanks for pointing out this about 3dNow!.