Mercurial > hg > Members > kono > nitros9-code
view docs/ccguide/crc.refentry @ 3140:03b580a02945
Allow CoCo3FPGA-specific build of superdesc.asm
Added new conditional CC3FPGA and code to "level1/modules/superdesc.asm"
to reflect changes needed to build the new SD card descriptors for the
Coco3FPGA.
author | Bill Pierce <merlinious999@gmail.com> |
---|---|
date | Sat, 04 Feb 2017 11:06:26 +0100 |
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>