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Subject: Re: Design choices in Crafty

Author: Dieter Buerssner

Date: 15:03:42 06/24/04

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On June 24, 2004 at 09:03:57, Gian-Carlo Pascutto wrote:

>On June 24, 2004 at 07:56:32, Anthony Cozzie wrote:
>>Switch is _fast_.  Again, in assembly:
>>
>>  and eax, 0xF
>>  jmp table[eax]
>
>An indirect jmp fast?
>
>Are you joking?
>
>Also good luck with getting the compiler to generate that code.

I don't understand. My compilers are able to generate fast code for switch. When
the cases are "dense" the code will be similar to the code shown by Anthony. The
and will probably be not there for typical simple switches. There might be a
branch instruction instead (which never will be taken - so it should be
perfectly predicted). Eugene has shown, how one can convince MSVC to not issue
that branch, either.

Regards,
Dieter



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