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Diffstat (limited to 'trunk/codecs/lpc10/ham84.c')
| -rw-r--r-- | trunk/codecs/lpc10/ham84.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/trunk/codecs/lpc10/ham84.c b/trunk/codecs/lpc10/ham84.c new file mode 100644 index 000000000..fddd8f3c0 --- /dev/null +++ b/trunk/codecs/lpc10/ham84.c @@ -0,0 +1,126 @@ +/* + +$Log$ +Revision 1.15 2004/06/26 03:50:14 markster +Merge source cleanups (bug #1911) + +Revision 1.14 2003/02/12 13:59:15 matteo +mer feb 12 14:56:57 CET 2003 + +Revision 1.1.1.1 2003/02/12 13:59:15 matteo +mer feb 12 14:56:57 CET 2003 + +Revision 1.2 2000/01/05 08:20:39 markster +Some OSS fixes and a few lpc changes to make it actually work + + * Revision 1.1 1996/08/19 22:32:07 jaf + * Initial revision + * + +*/ + +/* -- translated by f2c (version 19951025). + You must link the resulting object file with the libraries: + -lf2c -lm (in that order) +*/ + +#include "f2c.h" + +#ifdef P_R_O_T_O_T_Y_P_E_S +extern int ham84_(integer *input, integer *output, integer *errcnt); +#endif + +/* ***************************************************************** */ + +/* HAM84 Version 45G */ + +/* $Log$ + * Revision 1.15 2004/06/26 03:50:14 markster + * Merge source cleanups (bug #1911) + * + * Revision 1.14 2003/02/12 13:59:15 matteo + * mer feb 12 14:56:57 CET 2003 + * + * Revision 1.1.1.1 2003/02/12 13:59:15 matteo + * mer feb 12 14:56:57 CET 2003 + * + * Revision 1.2 2000/01/05 08:20:39 markster + * Some OSS fixes and a few lpc changes to make it actually work + * + * Revision 1.1 1996/08/19 22:32:07 jaf + * Initial revision + * */ +/* Revision 1.3 1996/03/21 15:26:00 jaf */ +/* Put comment header in standard form. */ + +/* Revision 1.2 1996/03/13 22:00:13 jaf */ +/* Comments added explaining that none of the local variables of this */ +/* subroutine need to be saved from one invocation to the next. */ + +/* Revision 1.1 1996/02/07 14:47:04 jaf */ +/* Initial revision */ + + +/* ***************************************************************** */ + +/* Hamming 8,4 Decoder - can correct 1 out of seven bits */ +/* and can detect up to two errors. */ + +/* Input: */ +/* INPUT - Seven bit data word, 4 bits parameter and */ +/* 4 bits parity information */ +/* Input/Output: */ +/* ERRCNT - Sums errors detected by Hamming code */ +/* Output: */ +/* OUTPUT - 4 corrected parameter bits */ + +/* This subroutine is entered with an eight bit word in INPUT. The 8th */ +/* bit is parity and is stripped off. The remaining 7 bits address the */ +/* hamming 8,4 table and the output OUTPUT from the table gives the 4 */ +/* bits of corrected data. If bit 4 is set, no error was detected. */ +/* ERRCNT is the number of errors counted. */ + +/* This subroutine has no local state. */ + +/* Subroutine */ int ham84_(integer *input, integer *output, integer *errcnt) +{ + /* Initialized data */ + + static integer dactab[128] = { 16,0,0,3,0,5,14,7,0,9,14,11,14,13,30,14,0, + 9,2,7,4,7,7,23,9,25,10,9,12,9,14,7,0,5,2,11,5,21,6,5,8,11,11,27, + 12,5,14,11,2,1,18,2,12,5,2,7,12,9,2,11,28,12,12,15,0,3,3,19,4,13, + 6,3,8,13,10,3,13,29,14,13,4,1,10,3,20,4,4,7,10,9,26,10,4,13,10,15, + 8,1,6,3,6,5,22,6,24,8,8,11,8,13,6,15,1,17,2,1,4,1,6,15,8,1,10,15, + 12,15,15,31 }; + + integer i__, j, parity; + +/* Arguments */ +/* Parameters/constants */ +/* Local variables that need not be saved */ +/* Determine parity of input word */ + parity = *input & 255; + parity ^= parity / 16; + parity ^= parity / 4; + parity ^= parity / 2; + parity &= 1; + i__ = dactab[*input & 127]; + *output = i__ & 15; + j = i__ & 16; + if (j != 0) { +/* No errors detected in seven bits */ + if (parity != 0) { + ++(*errcnt); + } + } else { +/* One or two errors detected */ + ++(*errcnt); + if (parity == 0) { +/* Two errors detected */ + ++(*errcnt); + *output = -1; + } + } + return 0; +} /* ham84_ */ + |