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Re: faster "CRC"- / "FNV"-hashing

From Bonita Montero <Bonita.Montero@gmail.com>
Newsgroups comp.lang.c++
Subject Re: faster "CRC"- / "FNV"-hashing
Date 2021-10-11 10:53 +0200
Organization A noiseless patient Spider
Message-ID <sk0u2a$ajc$1@dont-email.me> (permalink)
References (1 earlier) <3TP8J.82248$tG6.21234@fx39.iad> <sk0lga$94q$1@dont-email.me> <WTQ8J.225542$T_8.141095@fx48.iad> <sk0lrs$fvr$1@dont-email.me> <TZR8J.11209$yk1.5819@fx13.iad>

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Am 11.10.2021 um 09:46 schrieb Branimir Maksimovic:
> On 2021-10-11, Bonita Montero <Bonita.Montero@gmail.com> wrote:
>> Am 11.10.2021 um 08:32 schrieb Branimir Maksimovic:
>>
>>>> CRC64_ECMA182::crc64_table::crc64_table()
>>>> {
>>>> 	uint64_t const CRC64_ECMA182_POLY = 0x42F0E1EBA9EA3693u;
>>>> 	for( uint64_t i = 0; i != 256; ++i )
>>>> 	{
>>>> 		uint64_t crc = 0,
>>>> 		         c   = i << 56;
>>>> 		for( unsigned j = 0; j != 8; ++j )
>>>> 			crc = (int64_t)(crc ^ c) < 0 ? (crc << 1) ^ CRC64_ECMA182_POLY : crc
>>>> << 1,
>>>> 			c <<= 1;
>>>> 		t[(size_t)i] = crc;
>>>> 	}
>>>> }
>>>>
>>>> CRC64_ECMA182::crc64_table CRC64_ECMA182::table;
>>>>
>>>> Why does it run faster ?
>>> Dunno, haven't have need to calculate crc64 yet :P
>>> Better to generate table, don't waste time on generation :P
>>
>> Eeeh, I'm using also a table as you can see from above.
>>
>>
> What do you think about following:
> https://github.com/intel/isa-l/tree/master/crc

I won't check this ASM-code. An I don't know why people use ASM.
C / C++ and intrinsics usually result in better code.

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Thread

faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-10 18:51 +0200
  Re: faster "CRC"- / "FNV"-hashing "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-10-10 12:36 -0700
    Re: faster "CRC"- / "FNV"-hashing scott@slp53.sl.home (Scott Lurndal) - 2021-10-10 22:51 +0000
      Re: faster "CRC"- / "FNV"-hashing "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-10-12 13:47 -0700
    Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 08:09 +0200
  Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 05:23 +0000
    Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 08:15 +0200
      Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 06:29 +0000
        Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 08:34 +0200
    Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 08:27 +0200
      Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 06:32 +0000
        Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 08:33 +0200
          Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 07:46 +0000
            Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 10:53 +0200
              Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 09:11 +0000
                Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 11:18 +0200
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 10:42 +0000
                Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 13:03 +0200
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 11:12 +0000
                Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 13:44 +0200
                Re: faster "CRC"- / "FNV"-hashing Bo Persson <bo@bo-persson.se> - 2021-10-11 13:58 +0200
                Re: faster "CRC"- / "FNV"-hashing David Brown <david.brown@hesbynett.no> - 2021-10-11 14:23 +0200
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 12:56 +0000
                Re: faster "CRC"- / "FNV"-hashing Bonita Montero <Bonita.Montero@gmail.com> - 2021-10-11 15:55 +0200
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 16:55 +0000
                Re: faster "CRC"- / "FNV"-hashing RadicalRabbit@theburrow.co.uk - 2021-10-12 09:06 +0000
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-12 11:01 +0000
                Re: faster "CRC"- / "FNV"-hashing RadicalRabbit@theburrow.co.uk - 2021-10-12 14:49 +0000
                Re: faster "CRC"- / "FNV"-hashing David Brown <david.brown@hesbynett.no> - 2021-10-11 17:19 +0200
                Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 16:57 +0000
  Re: faster "CRC"- / "FNV"-hashing Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2021-10-11 05:41 +0000

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