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Bug fix in binary shift operand (_rotl) used by GPS telemetry decoder that caused problems in 64 bits systems.

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git-svn-id: https://svn.code.sf.net/p/gnss-sdr/code/trunk@451 64b25241-fba3-4117-9849-534c7e92360d
This commit is contained in:
Javier Arribas 2013-11-26 09:41:14 +00:00
parent d7a5998dd2
commit fc317810cc
1 changed files with 9 additions and 11 deletions
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20
src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_cc.cc
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@ -46,8 +46,8 @@
#include "gnss_synchro.h" #include "gnss_synchro.h"
#ifndef _lrotl #ifndef _rotl
#define _lrotl(X,N) ((X << N) ^ (X >> (32-N))) // Used in the parity check algorithm #define _rotl(X,N) ((X << N) ^ (X >> (32-N))) // Used in the parity check algorithm
#endif #endif
using google::LogMessage; using google::LogMessage;
@ -154,23 +154,21 @@ bool gps_l1_ca_telemetry_decoder_cc::gps_word_parityCheck(unsigned int gpsword)
check algorithm described in IS-GPS-200E. This avoids lengthy shift- check algorithm described in IS-GPS-200E. This avoids lengthy shift-
and-xor loops. */ and-xor loops. */
d1 = gpsword & 0xFBFFBF00; d1 = gpsword & 0xFBFFBF00;
d2 = _lrotl(gpsword,1) & 0x07FFBF01; d2 = _rotl(gpsword,1) & 0x07FFBF01;
d3 = _lrotl(gpsword,2) & 0xFC0F8100; d3 = _rotl(gpsword,2) & 0xFC0F8100;
d4 = _lrotl(gpsword,3) & 0xF81FFE02; d4 = _rotl(gpsword,3) & 0xF81FFE02;
d5 = _lrotl(gpsword,4) & 0xFC00000E; d5 = _rotl(gpsword,4) & 0xFC00000E;
d6 = _lrotl(gpsword,5) & 0x07F00001; d6 = _rotl(gpsword,5) & 0x07F00001;
d7 = _lrotl(gpsword,6) & 0x00003000; d7 = _rotl(gpsword,6) & 0x00003000;
t = d1 ^ d2 ^ d3 ^ d4 ^ d5 ^ d6 ^ d7; t = d1 ^ d2 ^ d3 ^ d4 ^ d5 ^ d6 ^ d7;
// Now XOR the 5 6-bit fields together to produce the 6-bit final result. // Now XOR the 5 6-bit fields together to produce the 6-bit final result.
parity = t ^ _lrotl(t,6) ^ _lrotl(t,12) ^ _lrotl(t,18) ^ _lrotl(t,24); parity = t ^ _rotl(t,6) ^ _rotl(t,12) ^ _rotl(t,18) ^ _rotl(t,24);
parity = parity & 0x3F; parity = parity & 0x3F;
if (parity == (gpsword & 0x3F)) return(true); if (parity == (gpsword & 0x3F)) return(true);
else return(false); else return(false);
} }
int gps_l1_ca_telemetry_decoder_cc::general_work (int noutput_items, gr_vector_int &ninput_items, int gps_l1_ca_telemetry_decoder_cc::general_work (int noutput_items, gr_vector_int &ninput_items,
gr_vector_const_void_star &input_items, gr_vector_void_star &output_items) gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
{ {