Author: Vincent Lejeune
Date: 15:15:27 11/27/99
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On November 27, 1999 at 17:04:11, Eugene Nalimov wrote: >On November 27, 1999 at 08:59:51, Vincent Diepeveen wrote: > >>On November 27, 1999 at 04:16:53, blass uri wrote: >> >>>Does someone know about a book about the fastest C program to do simple tasks? >>>(for example to find if a number is a prime) >> >>>I think that knowing this information can help to think about ideas how to do >>>chess programs faster. >> >>Let's please distinguish two things >> - used algorithm >> - used implementation >> >>You can make a very good optimized program A to generate primes, >>but a silly implemented other program B might generate at the same >>hardware a lot faster primes using a better algorithm. >> >>In general people then say that program A sucks and that a program B is >>wonderful... ...yet from programming viewpoint this is rather hard to do. >> >>>I understand that +- operations are faster than */ operations but I do not know >>>how much faster and if it is dependent on the computer. >> >>That depends upon architecture. >>Multiply is in general not slower than incrementing with a register. >>I'm using a lot of multiples in my DIEP's eval. >> >>At the P5 it sure is very slow. At the PRO/PII/PIII/Xeon it isn't. >>Don't know about the K7, but i bet it's not slower there either, as >>DIEP runs 15.5% faster on a K7 than on a PIII at the same Mhz. >> >>>Where can I get information like this information? >> >>www.intel.com >> >>Go to the technical references of the CPUs. >>K7 is harder. >> >>>I can find it by doing a simple program but I prefer not to check everything >>>about speed by testing because I may have many question like this question. >>>Uri >> >>Rather hard to find it by doing a simple program, measuring things >>accurately is also an art in itselve. >> >>What is however slowing down programs most is not the clocks needed to >>do an integer multiplication. The real problem are branches. At the >>Merced this should all be solved, so i wonder why the first vague reports >>about the merced don't say it to be a lot faster than the 21264 cpu. > >Yes, but at IA-64 multiplication is *very* slow. > >Eugene How is it possible and why intel did that ??
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