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From: tmoran@acm.org
Newsgroups: comp.lang.ada
Subject: Re: crc and Ada
References: <slrnbcec3j.rh.swierczu@staticline881.toya.net.pl>
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Xref: archiver1.google.com comp.lang.ada:37468
Date: 2003-05-18T07:56:28+00:00
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> I'm starting in Ada, and I can't use same operators (like xor, and) in
Take another look at your Ada text.  There are indeed "and", "xor" etc
operators for modular (unsigned) types.

> crc=(crctable[((crc>>8)^bufor[start+i++]) & 0xFF]^(crc<<8))&0xFFFF;

type crc_type is mod 2**16;
crc : crc_type := initial value
type byte is mod 256;
crc_table : array(byte) of crc_type;

for i in start .. finish loop
  crc:=crc_table(byte(crc/256) xor bufor(i)) xor ((crc mod 256)*256);
end loop;