annotate loadtools/hexdecode.c @ 148:0e7a85356130

doc/RF_tables write-up added
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 27 Feb 2017 08:34:31 +0000
parents e7502631a0f9
children
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1 /*
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2 * This module contains the decode_hex_byte() function,
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3 * which is used by the SREC file reader and will likely be used
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4 * by other code as well, such as the dump-to-file function
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5 * of loadtool.
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6 */
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7
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8 #include <ctype.h>
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9
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10 decode_hex_byte(s)
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11 char *s;
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12 {
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13 register int u, l;
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14
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15 if (!isxdigit(s[0]) || !isxdigit(s[1]))
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16 return(-1);
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17 if (isdigit(s[0]))
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18 u = s[0] - '0';
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19 else if (isupper(s[0]))
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20 u = s[0] - 'A' + 10;
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21 else
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22 u = s[0] - 'a' + 10;
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23 if (isdigit(s[1]))
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24 l = s[1] - '0';
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25 else if (isupper(s[1]))
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26 l = s[1] - 'A' + 10;
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27 else
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28 l = s[1] - 'a' + 10;
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29 return((u << 4) | l);
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30 }