view docs/ccguide/crc.refentry @ 3220:9ccec98c9897

Updated IDE Driver makefile so it will have place holders for dsk, dskclean, and dskcopy so that make does not error out when chaining into the driver tree to build disk images where applicable.
author David Ladd <drencor-xeen@users.sourceforge.net>
date Wed, 20 Dec 2017 16:10:50 -0600
parents c0da1728ed5b
children
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<refentry id="crc">
<refnamediv>
<refname>Crc</refname>
<refpurpose>compute a cyclic redundancy count</refpurpose>
</refnamediv>

<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
  <funcdef><function>crc</function></funcdef>
  <paramdef>char *<parameter>start</parameter></paramdef>
  <paramdef>int <parameter>count</parameter></paramdef>
  <paramdef>char <parameter>accum</parameter>[3]</paramdef>
</funcprototype>
</funcsynopsis>

</refsynopsisdiv>

<refsect1><title>Assembler Equivalent</title>
<para>
os9 F$CRC
</para>
</refsect1>

<refsect1><title>Description</title>
<para>
This call accumulates a crc into a three byte array at "accum"
for "count" bytes starting at "start". All three bytes of
"accum" should be initialized to 0xff before the first call to
"crc()". However, repeated calls can be subsequently made to
cover an entire module. If the result is to be used as an OS-9
module crc, it should have its bytes complemented before
insertion at the end of the module.
</para>
</refsect1>
</refentry>