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This thread is about high performance. I.e. desktop, workstation, server processors. > Why are x86/64 processors used for most high performance applications th
by dom0 10y ago
This thread is about high performance. I.e. desktop, workstation, server processors.
> Why are x86/64 processors used for most high performance applications then?
Also ARM, the architecture where most cores have between three and four distinct frontends, hardly qualifies as R ISC.
- pcwalton 10y agoEven with the complexity of Thumb-1, Thumb-2, and NEON, I'd give the edge to ARM in simplicity. At least the instruction encodings for ARM make sense, even today. x86 instruction decoding is absurd. More importantly, ARM has a way to massively reduce its decoding complexity, via AArch64. AArch64 is a separate RISC instruction set, with room explicitly left in the design for dropping 32-bit ARM in the future (32-bit support is optional, though in practice today everyone includes it). ARM is effectively in the process of making a transition to a more RISC-like ISA, unlike Intel which has no realistic way to get there.
- wolfgke 10y ago> Even with the complexity of Thumb-1, Thumb-2, and NEON, I'd give the edge to ARM in simplicity. At least the instruction encodings for ARM make sense, even today. x86 instruction decoding is absurd. If you write down the x86 instruction encoding in octal, it makes a lot more sense: > http://www.dabo.de/ccc99/www.camp.ccc.de/radio/help.txt http://www.dabo.de/ccc99/www.camp.ccc.de/radio/help.txt
- pcwalton 10y agoFor the 8086, sure. But modern x86 throws in Mod R/M, SIB bytes, REX prefixes, VEX prefixes, Operand Size Overrides…