From: segaloco via TUHS <tuhs@tuhs.org>
To: The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: [TUHS] Re: CRC calculation in the 1980s
Date: Tue, 19 Sep 2023 00:02:50 +0000 [thread overview]
Message-ID: <S3imRO8aA0tSfOAAkBxcCwQp18JuPd2-aLNkvVvJF1l0tGGDl2q8eIaqgmccNvZWPKiofXhe8r5ajbNuT0ckmNbOfLqsvK_rxgVm-1UMKCY=@protonmail.com> (raw)
In-Reply-To: <87246EC9-0AC8-404E-A8DD-508AB046018B@planet.nl>
> Any suggestions as to why the on-the-fly algorithm did not catch on more in the 1980’s? Maybe it was simply less well known than I think?
The CRC algorithm I'm familiar with shows up in Dragon Quest for the Famicom in 1986[1], written in 6502 assembly. Admittedly though I only recognized it due to the EOR with 0x1021 on lines 318-323. That I then only know from a quick and dirty CRC I threw in an XMODEM-CRC client [2] I did to accommodate for a bug in the JH7100 RISC-V board's recovery ROM implementation. Not sure if this is along the lines of the approach you're talking about, admittedly these two instances are literally all I know about CRC, just enough to be dangerous :)
Still, a concrete example of ChunSoft's 6502 CRC calculation in the mid 80s, if that helps with the assessment of the time period/flow of ideas in the industry.
- Matt G.
[1] - https://gitlab.com/segaloco/dq1disasm/-/blob/master/src/chr3/start_pw.s
[2] - https://gitlab.com/segaloco/riscv-bits/-/blob/master/util/sxj.c
next prev parent reply other threads:[~2023-09-19 0:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-18 23:02 [TUHS] " Paul Ruizendaal
2023-09-18 23:34 ` [TUHS] " Robert Brockway
2023-09-19 0:02 ` segaloco via TUHS [this message]
2023-09-19 15:34 ` Paul Winalski
2023-09-19 15:50 ` Dan Cross
2023-09-19 16:22 ` Paul Winalski
2023-09-19 11:42 Noel Chiappa
2023-09-19 12:54 ` Lars Brinkhoff
2023-09-19 16:00 ` Paul Ruizendaal
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