view loadtools/hexdecode.c @ 636:3172e3111ab7

loadtools/romload.c: implemented grouping of S-records into bigger blocks
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 01 Mar 2020 05:40:29 +0000
parents e7502631a0f9
children
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/*
 * This module contains the decode_hex_byte() function,
 * which is used by the SREC file reader and will likely be used
 * by other code as well, such as the dump-to-file function
 * of loadtool.
 */

#include <ctype.h>

decode_hex_byte(s)
	char *s;
{
	register int u, l;

	if (!isxdigit(s[0]) || !isxdigit(s[1]))
		return(-1);
	if (isdigit(s[0]))
		u = s[0] - '0';
	else if (isupper(s[0]))
		u = s[0] - 'A' + 10;
	else
		u = s[0] - 'a' + 10;
	if (isdigit(s[1]))
		l = s[1] - '0';
	else if (isupper(s[1]))
		l = s[1] - 'A' + 10;
	else
		l = s[1] - 'a' + 10;
	return((u << 4) | l);
}