csu3_am335x/EVSE/GPL/plc-utils.LNX.2.1.20/source/tools/memdecr.c

/*====================================================================*
 *
 *   signed memdecr (void * memory, size_t extent);
 *
 *   memory.h
 *
 *   decrement a multi-byte memory region; start at 0xff and reset 
 *   at 0x00; return -1 if all bytes are 0x00;
 *
 *   for example:
 *
 *      0x00 0x00 0x00 --> 0x00 0x00 0x01
 *      0xFF 0x00 0xFF --> 0xFF 0x01 0x00
 *
 *   Motley Tools by Charles Maier <cmaier@cmassoc.net>;
 *   Copyright (c) 2001-2006 by Charles Maier Associates;
 *   Licensed under the Internet Software Consortium License;
 *
 *--------------------------------------------------------------------*/

#ifndef MEMDECR_SOURCE
#define MEMDECR_SOURCE

#include "../tools/memory.h"

signed memdecr (void * memory, register size_t extent) 

{ 
	register byte * offset = (byte *) (memory); 
	while (extent--) 
	{ 
		if (-- offset [extent] != 0xFF) 
		{ 
			return (0); 
		} 
	} 
	return (- 1); 
} 

#endif