From 7a743398cf4738e58a7a57f94dc079a6c529829d Mon Sep 17 00:00:00 2001 From: leo Date: Wed, 20 Feb 2008 02:28:51 +0000 Subject: channel decoding (gsmstack) --- gsm-tvoid/src/lib/burst_types.h | 213 ++++++++++++++++++ gsm-tvoid/src/lib/conv.c | 487 ++++++++++++++++++++++++++++++++++++++++ gsm-tvoid/src/lib/conv.h | 42 ++++ gsm-tvoid/src/lib/gsm_burst.cc | 35 ++- gsm-tvoid/src/lib/gsmstack.c | 74 ++++++ gsm-tvoid/src/lib/gsmstack.h | 21 ++ gsm-tvoid/src/lib/interleave.c | 47 ++++ gsm-tvoid/src/lib/interleave.h | 18 ++ gsm-tvoid/src/lib/sch.c | 323 ++++++++++++++++++++++++++ gsm-tvoid/src/lib/sch.h | 16 ++ gsm-tvoid/src/lib/system.h | 11 + 11 files changed, 1286 insertions(+), 1 deletion(-) create mode 100644 gsm-tvoid/src/lib/burst_types.h create mode 100644 gsm-tvoid/src/lib/conv.c create mode 100644 gsm-tvoid/src/lib/conv.h create mode 100644 gsm-tvoid/src/lib/gsmstack.c create mode 100644 gsm-tvoid/src/lib/gsmstack.h create mode 100644 gsm-tvoid/src/lib/interleave.c create mode 100644 gsm-tvoid/src/lib/interleave.h create mode 100644 gsm-tvoid/src/lib/sch.c create mode 100644 gsm-tvoid/src/lib/sch.h create mode 100644 gsm-tvoid/src/lib/system.h (limited to 'gsm-tvoid') diff --git a/gsm-tvoid/src/lib/burst_types.h b/gsm-tvoid/src/lib/burst_types.h new file mode 100644 index 0000000..90d35ad --- /dev/null +++ b/gsm-tvoid/src/lib/burst_types.h @@ -0,0 +1,213 @@ +// $Id: burst_types.h,v 1.5 2007/03/14 05:44:53 jl Exp $ + +#pragma once + +#ifdef __cplusplus +extern "C" { +#endif + +#include "gsm_constants.h" + +static const int TB_LEN = 3; +static const int TB_OS1 = 0; +static const int TB_OS2 = 145; +static const unsigned char tail_bits[] = {0, 0, 0}; + +/* + * The normal burst is used to carry information on traffic and control + * channels. + */ +static const int N_TSC_NUM = 8; // number of training sequence codes +static const int N_TSC_CODE_LEN = 26; // length of tsc +static const int N_TSC_OS = 61; // tsc offset +static const int N_EDATA_LEN_1 = 58; // length of first data section +static const int N_EDATA_OS_1 = 3; // offset of first data section +static const int N_EDATA_LEN_2 = 58; // length of second data section +static const int N_EDATA_OS_2 = 87; // offset of second data section +#if 0 +static const unsigned char n_tsc[][N_TSC_CODE_LEN] = { +/* 0 */ { + 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, + 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1 + }, +/* 1 */ { + 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, + 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1 + }, +/* 2 */ { + 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, + 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0 + }, +/* 3 */ { + 0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, + 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0 + }, +/* 4 */ { + 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, + 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1 + }, +/* 5 */ { + 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, + 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0 + }, +/* 6 */ { + 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, + 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1 + }, +/* 7 */ { + 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, + 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0 + } +}; + +#endif + +/* + * The frequency correction burst is used for frequency synchronization + * of the mobile. This is broadcast in TS0 together with the SCH and + * BCCH. + * + * Modulating the bits below causes a spike at 62.5kHz above (below for + * COMPACT) the center frequency. One can use this spike with a narrow + * band filter to accurately determine the center of the channel. + */ +static const int FC_CODE_LEN = 142; +static const int FC_OS = 3; +static const unsigned char fc_fb[] = { + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 +}; + +static const unsigned char fc_compact_fb[] = { + 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, + 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, + 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, + 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, + 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, + 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, + 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, + 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, + 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0 +}; + + +/* + * The synchronization burst is used for time synchronization of the + * mobile. The bits given below were chosen for their correlation + * properties. The synchronization channel (SCH) contains a long + * training sequence (given below) and carries the TDMA frame number and + * base station identity code. It is broadcast in TS0 in the frame + * following the frequency correction burst. + */ +static const int SB_CODE_LEN = 64; +static const int SB_ETS_OS = 42; +static const int SB_EDATA_LEN_1 = 39; +static const int SB_EDATA_OS_1 = 3; +static const int SB_EDATA_LEN_2 = 39; +static const int SB_EDATA_OS_2 = 106; +static const unsigned char sb_etsc[] = { + 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, + 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, + 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, + 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1 +}; + +static const unsigned char sb_cts_etsc[] = { + 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, + 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, + 1, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, + 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 1 +}; + +static const unsigned char sb_compact_etsc[] = { + 1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, + 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, + 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, + 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0 +}; + + +/* + * A base tranceiver station must transmit a burst in every timeslot of + * every TDMA frame in channel C0. The dummy burst will be transmitted + * on all timeslots of all TDMA frames for which no other channel + * requires a burst to be transmitted. + */ +static const int D_CODE_LEN = 142; +static const int D_MB_OS = 3; +static const unsigned char d_mb[] = { + 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, + 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, + 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, + 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, + 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, + 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, + 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, + 0, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0 +}; + + +/* + * The access burst is used for random access from a mobile. + */ +static const int AB_ETB_CODE_LEN = 8; +static const int AB_ETB_OS = 0; +static const unsigned char ab_etb[] = { + 0, 0, 1, 1, 1, 0, 1, 0 +}; + +static const int AB_SSB_CODE_LEN = 41; +static const int AB_SSB_OS = 8; +static const unsigned char ab_ssb[] = { + 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, + 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, + 0, 0, 1, 1, 1, 1, 0, 0, 0 +}; + +static const unsigned char ab_ts1_ssb[] = { + 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, + 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 1, + 0, 0, 1, 0, 0, 1, 1, 0, 1 +}; + +static const unsigned char ab_ts2_ssb[] = { + 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, + 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, + 1, 0, 1, 1, 1, 0, 1, 1, 1 +}; + + +typedef enum { + burst_n_0, + burst_n_1, + burst_n_2, + burst_n_3, + burst_n_4, + burst_n_5, + burst_n_6, + burst_n_7, + burst_fc, + burst_fc_c, + burst_s, + burst_s_cts, + burst_s_c, + burst_d, + burst_a, + burst_a_ts1, + burst_a_ts2, + burst_not_a_burst +} burst_t; + +static const int N_BURST_TYPES = ((int)(burst_not_a_burst) + 1); + +#ifdef __cplusplus +} +#endif diff --git a/gsm-tvoid/src/lib/conv.c b/gsm-tvoid/src/lib/conv.c new file mode 100644 index 0000000..eb97e30 --- /dev/null +++ b/gsm-tvoid/src/lib/conv.c @@ -0,0 +1,487 @@ +#include +#include +#include +#include +#include + +#include + +//#include "burst_types.h" +#include "conv.h" +//#include "fire_crc.h" + + +/* + * GSM SACCH -- Slow Associated Control Channel + * + * These messages are encoded exactly the same as on the BCCH. + * (Broadcast Control Channel.) + * + * Input: 184 bits + * + * 1. Add parity and flushing bits. (Output 184 + 40 + 4 = 228 bit) + * 2. Convolutional encode. (Output 228 * 2 = 456 bit) + * 3. Interleave. (Output 456 bit) + * 4. Map on bursts. (4 x 156 bit bursts with each 2x57 bit content data) + */ + + +/* + * Parity (FIRE) for the GSM SACCH channel. + * + * g(x) = (x^23 + 1)(x^17 + x^3 + 1) + * = x^40 + x^26 + x^23 + x^17 + x^3 + 1 + */ + +static const unsigned char parity_polynomial[PARITY_SIZE + 1] = { + 1, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 1, 0, + 0, 1, 0, 0, 0, 0, 0, 1, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 1, 0, 0, + 1 +}; + +// remainder after dividing data polynomial by g(x) +static const unsigned char parity_remainder[PARITY_SIZE] = { + 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1 +}; + + +/* +static void parity_encode(unsigned char *d, unsigned char *p) { + + int i; + unsigned char buf[DATA_BLOCK_SIZE + PARITY_SIZE], *q; + + memcpy(buf, d, DATA_BLOCK_SIZE); + memset(buf + DATA_BLOCK_SIZE, 0, PARITY_SIZE); + + for(q = buf; q < buf + DATA_BLOCK_SIZE; q++) + if(*q) + for(i = 0; i < PARITY_SIZE + 1; i++) + q[i] ^= parity_polynomial[i]; + for(i = 0; i < PARITY_SIZE; i++) + p[i] = !buf[DATA_BLOCK_SIZE + i]; +} + */ + + +int +parity_check(unsigned char *d) { + + unsigned int i; + unsigned char buf[DATA_BLOCK_SIZE + PARITY_SIZE], *q; + + memcpy(buf, d, DATA_BLOCK_SIZE + PARITY_SIZE); + + for(q = buf; q < buf + DATA_BLOCK_SIZE; q++) + if(*q) + for(i = 0; i < PARITY_SIZE + 1; i++) + q[i] ^= parity_polynomial[i]; + return memcmp(buf + DATA_BLOCK_SIZE, parity_remainder, PARITY_SIZE); +} + + +/* + * Convolutional encoding and Viterbi decoding for the GSM SACCH channel. + */ + +/* + * Convolutional encoding: + * + * G_0 = 1 + x^3 + x^4 + * G_1 = 1 + x + x^3 + x^4 + * + * i.e., + * + * c_{2k} = u_k + u_{k - 3} + u_{k - 4} + * c_{2k + 1} = u_k + u_{k - 1} + u_{k - 3} + u_{k - 4} + */ +#define K 5 +#define MAX_ERROR (2 * CONV_INPUT_SIZE + 1) + + +/* + * Given the current state and input bit, what are the output bits? + * + * encode[current_state][input_bit] + */ +static const unsigned int encode[1 << (K - 1)][2] = { + {0, 3}, {3, 0}, {3, 0}, {0, 3}, + {0, 3}, {3, 0}, {3, 0}, {0, 3}, + {1, 2}, {2, 1}, {2, 1}, {1, 2}, + {1, 2}, {2, 1}, {2, 1}, {1, 2} +}; + + +/* + * Given the current state and input bit, what is the next state? + * + * next_state[current_state][input_bit] + */ +static const unsigned int next_state[1 << (K - 1)][2] = { + {0, 8}, {0, 8}, {1, 9}, {1, 9}, + {2, 10}, {2, 10}, {3, 11}, {3, 11}, + {4, 12}, {4, 12}, {5, 13}, {5, 13}, + {6, 14}, {6, 14}, {7, 15}, {7, 15} +}; + + +/* + * Given the previous state and the current state, what input bit caused + * the transition? If it is impossible to transition between the two + * states, the value is 2. + * + * prev_next_state[previous_state][current_state] + */ +static const unsigned int prev_next_state[1 << (K - 1)][1 << (K - 1)] = { + { 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2}, + { 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2}, + { 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2}, + { 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2}, + { 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2}, + { 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2}, + { 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2}, + { 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2}, + { 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2}, + { 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2}, + { 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2}, + { 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2}, + { 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2}, + { 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2}, + { 2, 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1}, + { 2, 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1} +}; + + +static inline unsigned int hamming_distance2(unsigned int w) { + + return (w & 1) + !!(w & 2); +} + + +/* +static void conv_encode(unsigned char *data, unsigned char *output) { + + unsigned int i, state = 0, o; + + // encode data + for(i = 0; i < CONV_INPUT_SIZE; i++) { + o = encode[state][data[i]]; + state = next_state[state][data[i]]; + *output++ = !!(o & 2); + *output++ = o & 1; + } +} + */ + + +int +conv_decode(unsigned char *output, unsigned char *data) { + + int i, t; + unsigned int rdata, state, nstate, b, o, distance, accumulated_error, + min_state, min_error, cur_state; + + unsigned int ae[1 << (K - 1)]; + unsigned int nae[1 << (K - 1)]; // next accumulated error + unsigned int state_history[1 << (K - 1)][CONV_INPUT_SIZE + 1]; + + // initialize accumulated error, assume starting state is 0 + for(i = 0; i < (1 << (K - 1)); i++) + ae[i] = nae[i] = MAX_ERROR; + ae[0] = 0; + + // build trellis + for(t = 0; t < CONV_INPUT_SIZE; t++) { + + // get received data symbol + rdata = (data[2 * t] << 1) | data[2 * t + 1]; + + // for each state + for(state = 0; state < (1 << (K - 1)); state++) { + + // make sure this state is possible + if(ae[state] >= MAX_ERROR) + continue; + + // find all states we lead to + for(b = 0; b < 2; b++) { + + // get next state given input bit b + nstate = next_state[state][b]; + + // find output for this transition + o = encode[state][b]; + + // calculate distance from received data + distance = hamming_distance2(rdata ^ o); + + // choose surviving path + accumulated_error = ae[state] + distance; + if(accumulated_error < nae[nstate]) { + + // save error for surviving state + nae[nstate] = accumulated_error; + + // update state history + state_history[nstate][t + 1] = state; + } + } + } + + // get accumulated error ready for next time slice + for(i = 0; i < (1 << (K - 1)); i++) { + ae[i] = nae[i]; + nae[i] = MAX_ERROR; + } + } + + // the final state is the state with the fewest errors + min_state = (unsigned int)-1; + min_error = MAX_ERROR; + for(i = 0; i < (1 << (K - 1)); i++) { + if(ae[i] < min_error) { + min_state = i; + min_error = ae[i]; + } + } + + // trace the path + cur_state = min_state; + for(t = CONV_INPUT_SIZE; t >= 1; t--) { + min_state = cur_state; + cur_state = state_history[cur_state][t]; // get previous + output[t - 1] = prev_next_state[cur_state][min_state]; + } + + // return the number of errors detected (hard-decision) + return min_error; +} + + +/* + * GSM SACCH interleaving and burst mapping + * + * Interleaving: + * + * Given 456 coded input bits, form 4 blocks of 114 bits: + * + * i(B, j) = c(n, k) k = 0, ..., 455 + * n = 0, ..., N, N + 1, ... + * B = B_0 + 4n + (k mod 4) + * j = 2(49k mod 57) + ((k mod 8) div 4) + * + * Mapping on Burst: + * + * e(B, j) = i(B, j) + * e(B, 59 + j) = i(B, 57 + j) j = 0, ..., 56 + * e(B, 57) = h_l(B) + * e(B, 58) = h_n(B) + * + * Where h_l(B) and h_n(B) are bits in burst B indicating flags. + */ + +/* +static void interleave(unsigned char *data, unsigned char *iBLOCK) { + + int j, k, B; + + // for each bit in input data + for(k = 0; k < CONV_SIZE; k++) { + B = k % 4; + j = 2 * ((49 * k) % 57) + ((k % 8) / 4); + iBLOCK[B * iBLOCK_SIZE + j] = data[k]; + } +} + */ + + +#if 0 +static void decode_interleave(unsigned char *data, unsigned char *iBLOCK) { + + int j, k, B; + + for(k = 0; k < CONV_SIZE; k++) { + B = k % 4; + j = 2 * ((49 * k) % 57) + ((k % 8) / 4); + data[k] = iBLOCK[B * iBLOCK_SIZE + j]; + } +} + +#endif + +/* +static void burstmap(unsigned char *iBLOCK, unsigned char *eBLOCK, + unsigned char hl, unsigned char hn) { + + int j; + + for(j = 0; j < 57; j++) { + eBLOCK[j] = iBLOCK[j]; + eBLOCK[j + 59] = iBLOCK[j + 57]; + } + eBLOCK[57] = hl; + eBLOCK[58] = hn; +} + */ + + +static void decode_burstmap(unsigned char *iBLOCK, unsigned char *eBLOCK, + unsigned char *hl, unsigned char *hn) { + + int j; + + for(j = 0; j < 57; j++) { + iBLOCK[j] = eBLOCK[j]; + iBLOCK[j + 57] = eBLOCK[j + 59]; + } + *hl = eBLOCK[57]; + *hn = eBLOCK[58]; +} + + +/* + * Transmitted bits are sent least-significant first. + */ +int +compress_bits(unsigned char *dbuf, int dbuf_len, + unsigned char *sbuf, int sbuf_len) { + + unsigned int i, j, c, pos = 0; + + if(dbuf_len < ((sbuf_len + 7) >> 3)) + return -1; + + for(i = 0; i < sbuf_len; i += 8) { + for(j = 0, c = 0; (j < 8) && (i + j < sbuf_len); j++) + c |= (!!sbuf[i + j]) << j; + dbuf[pos++] = c & 0xff; + } + return pos; +} + + +#if 0 +int get_ns_l3_len(unsigned char *data, unsigned int datalen) { + + if((data[0] & 3) != 1) { + fprintf(stderr, "error: get_ns_l3_len: pseudo-length reserved " + "bits bad (%2.2x)\n", data[0] & 3); + return -1; + } + return (data[0] >> 2); +} + +#endif + +#if 0 +static unsigned char *decode_sacch(unsigned char *e0, unsigned char *e1, + unsigned char *e2, unsigned char *e3, unsigned int *datalen) { + + int errors, len, data_size = (DATA_BLOCK_SIZE + 7) >> 3; + unsigned char conv_data[CONV_SIZE], iBLOCK[BLOCKS][iBLOCK_SIZE], + hl, hn, decoded_data[PARITY_OUTPUT_SIZE], *data; + + if(!(data = (unsigned char *)malloc(data_size))) { + throw std::runtime_error("error: decode_cch: malloc"); + } + + if(datalen) + *datalen = 0; + + // unmap the bursts + decode_burstmap(iBLOCK[0], e0, &hl, &hn); // XXX ignore stealing bits + decode_burstmap(iBLOCK[1], e1, &hl, &hn); + decode_burstmap(iBLOCK[2], e2, &hl, &hn); + decode_burstmap(iBLOCK[3], e3, &hl, &hn); + + // remove interleave + interleave_decode(&opt.ictx, conv_data, (unsigned char *)iBLOCK); + //decode_interleave(conv_data, (unsigned char *)iBLOCK); + + // Viterbi decode + errors = conv_decode(decoded_data, conv_data); + DEBUGF("conv_decode: %d\n", errors); + if (errors) + return NULL; + + // check parity + // If parity check error detected try to fix it. + if (parity_check(decoded_data)) + { + fire_crc crc(40, 184); + // fprintf(stderr, "error: sacch: parity error (%d)\n", errors); + unsigned char crc_result[224]; + if (crc.check_crc(decoded_data, crc_result) == 0) + { + errors = -1; + DEBUGF("error: sacch: parity error (%d)\n", errors); + return NULL; + } else { + memcpy(decoded_data, crc_result, sizeof crc_result); + errors = 0; + } + } + + if((len = compress_bits(data, data_size, decoded_data, + DATA_BLOCK_SIZE)) < 0) { + fprintf(stderr, "error: compress_bits\n"); + return 0; + } + if(len < data_size) { + fprintf(stderr, "error: buf too small (%d < %d)\n", + sizeof(data), len); + return 0; + } + + if(datalen) + *datalen = (unsigned int)len; + return data; +} + +#endif + +/* + * decode_cch + * + * Decode a "common" control channel. Most control channels use + * the same burst, interleave, Viterbi and parity configuration. + * The documentation for the control channels defines SACCH first + * and then just keeps referring to that. + * + * The current (investigated) list is as follows: + * + * BCCH Norm + * BCCH Ext + * PCH + * AGCH + * CBCH (SDCCH/4) + * CBCH (SDCCH/8) + * SDCCH/4 + * SACCH/C4 + * SDCCH/8 + * SACCH/C8 + * + * We provide two functions, one for where all four bursts are + * contiguous, and one where they aren't. + */ +#if 0 +unsigned char *decode_cch(unsigned char *e0, unsigned char *e1, + unsigned char *e2, unsigned char *e3, unsigned int *datalen) { + + return decode_sacch(e0, e1, e2, e3, datalen); +} + + +unsigned char *decode_cch(unsigned char *e, unsigned int *datalen) { + + return decode_sacch(e, e + eBLOCK_SIZE, e + 2 * eBLOCK_SIZE, + e + 3 * eBLOCK_SIZE, datalen); +} +#endif diff --git a/gsm-tvoid/src/lib/conv.h b/gsm-tvoid/src/lib/conv.h new file mode 100644 index 0000000..0d7505d --- /dev/null +++ b/gsm-tvoid/src/lib/conv.h @@ -0,0 +1,42 @@ + +/* + * decode_cch + * + * Decode a "common" control channel. Most control channels use + * the same burst, interleave, Viterbi and parity configuration. + * The documentation for the control channels defines SACCH first + * and then just keeps referring to that. + * + * The current (investigated) list is as follows: + * + * BCCH Norm + * BCCH Ext + * PCH + * AGCH + * CBCH (SDCCH/4) + * CBCH (SDCCH/8) + * SDCCH/4 + * SACCH/C4 + * SDCCH/8 + * SACCH/C8 + * + * We provide two functions, one for where all four bursts are + * contiguous, and one where they aren't. + */ + +#define DATA_BLOCK_SIZE 184 +#define PARITY_SIZE 40 +#define FLUSH_BITS_SIZE 4 +#define PARITY_OUTPUT_SIZE (DATA_BLOCK_SIZE + PARITY_SIZE + FLUSH_BITS_SIZE) + +#define CONV_INPUT_SIZE PARITY_OUTPUT_SIZE +#define CONV_SIZE (2 * CONV_INPUT_SIZE) + +#define BLOCKS 4 +#define iBLOCK_SIZE (CONV_SIZE / BLOCKS) +#define eBLOCK_SIZE (iBLOCK_SIZE + 2) + +int conv_decode(unsigned char *output, unsigned char *data); +int parity_check(unsigned char *data); +int compress_bits(unsigned char *dbuf, int dlen, unsigned char *src, int len); + diff --git a/gsm-tvoid/src/lib/gsm_burst.cc b/gsm-tvoid/src/lib/gsm_burst.cc index f367de2..5415b2f 100755 --- a/gsm-tvoid/src/lib/gsm_burst.cc +++ b/gsm-tvoid/src/lib/gsm_burst.cc @@ -9,6 +9,8 @@ #include #include #include +#include "system.h" +#include "gsmstack.h" gsm_burst::gsm_burst (void) : d_bbuf_pos(0), @@ -67,6 +69,8 @@ gsm_burst::gsm_burst (void) : fprintf(stdout,"\n"); } + /* Initialize GSM Stack */ + GS_new(&d_gs_ctx); } gsm_burst::~gsm_burst () @@ -99,6 +103,16 @@ void gsm_burst::print_bits(const float *data,int length) data[i] < 0 ? fprintf(stdout,"+") : fprintf(stdout,"."); } +void gsm_burst::soft2hardbit(char *dst, const float *data, int len) +{ + for (int i=0; i < len; i++) + { + if (data[i] < 0) + dst[i] = 0; + else + dst[i] = 1; + } +} void gsm_burst::print_burst(void) { @@ -125,13 +139,32 @@ void gsm_burst::print_burst(void) if ( print && (d_print_options & PRINT_BITS) ) { if (d_print_options & PRINT_ALL_BITS) + { print_bits(d_burst_buffer,BBUF_SIZE); - else + } else { + /* 142 useful bits: 2*58 + 26 training */ print_bits(d_burst_buffer + d_burst_start,USEFUL_BITS); + } fprintf(stdout," "); } + /* + * Pass information to GSM stack. GSM stack will try to extract + * information (fn, layer 2 messages, ...) + */ + + char buf[156]; + /* In hardbits include the 3 trial bits */ + /* FIXME: access burst has 8 trail bits? what is d_burst_start + * set to? make sure we start at the right position here. + */ + soft2hardbit(buf, d_burst_buffer + d_burst_start - 3, 156); + /* GS_process will differentially decode the data and then + * extract SCH infos (and later bcch infos). + */ + GS_process(&d_gs_ctx, d_ts, d_burst_type, buf); + if (print) { fprintf(stdout,"%d/%d/%+d/%lu/%lu ", diff --git a/gsm-tvoid/src/lib/gsmstack.c b/gsm-tvoid/src/lib/gsmstack.c new file mode 100644 index 0000000..9fc4868 --- /dev/null +++ b/gsm-tvoid/src/lib/gsmstack.c @@ -0,0 +1,74 @@ +/* + * Invoke gsmstack() with any kind of burst. Automaticly decode and retrieve + * information. + */ +#include "system.h" +#include +#include +#include +#include "gsmstack.h" +#include "gsm_constants.h" +#include "interleave.h" +#include "sch.h" + +INTERLEAVE_CTX ictx; + +static void +diff_decode(char *dst, char *src, int len) +{ + const unsigned char *end = src + len; + unsigned char last; + + src += 3; + last = 0; + memset(dst, 0, 3); + dst += 3; + + while (src < end) + { + *dst = !*src ^ last; + last = *dst; + src++; + dst++; + } +} + +/* + * Initialize a new GSMSTACK context. + */ +int +GS_new(GS_CTX *ctx) +{ + memset(ctx, 0, sizeof *ctx); + interleave_init(&ictx, 456, 114); + + return 0; +} + +/* + * 156 bit + */ +int +GS_process(GS_CTX *ctx, int ts, int type, char *data) +{ + int fn; + int bsic; + int ret; + char buf[156]; + + diff_decode(buf, data, 156); + + switch (type) + { + case SCH: + ret = decode_sch(buf, &fn, &bsic); + if (ret != 0) + break; + DEBUGF("FN %d, BSIC %d\n", fn, bsic); + break; + case NORMAL: + break; + } +} + + diff --git a/gsm-tvoid/src/lib/gsmstack.h b/gsm-tvoid/src/lib/gsmstack.h new file mode 100644 index 0000000..9f0d9d8 --- /dev/null +++ b/gsm-tvoid/src/lib/gsmstack.h @@ -0,0 +1,21 @@ + +#ifndef __GSMSTACK_H__ +#define __GSMSTACK_H__ 1 + +#ifdef __cplusplus +extern "C" { +#endif + +typedef struct +{ + int flags; +} GS_CTX; + +int GS_new(GS_CTX *ctx); +int GS_process(GS_CTX *ctx, int ts, int type, char *data); + +#ifdef __cplusplus +} +#endif + +#endif diff --git a/gsm-tvoid/src/lib/interleave.c b/gsm-tvoid/src/lib/interleave.c new file mode 100644 index 0000000..437ed92 --- /dev/null +++ b/gsm-tvoid/src/lib/interleave.c @@ -0,0 +1,47 @@ + +#include +#include +#include "interleave.h" + +int +interleave_init(INTERLEAVE_CTX *ictx, int size, int block_size) +{ + ictx->trans_size = size; + ictx->trans = (unsigned short *)malloc(size * sizeof *ictx->trans); + +// DEBUGF("size: %d\n", size); +// DEBUGF("Block size: %d\n", block_size); + int j, k, B; + for (k = 0; k < size; k++) + { + B = k % 4; + j = 2 * ((49 * k) % 57) + ((k % 8) / 4); + ictx->trans[k] = B * block_size + j; + /* Mapping: pos1 goes to pos2: pos1 -> pos2 */ +// DEBUGF("%d -> %d\n", ictx->trans[k], k); + } +// exit(0); + return 0; +} + +int +interleave_deinit(INTERLEAVE_CTX *ictx) +{ + if (ictx->trans != NULL) + { + free(ictx->trans); + ictx->trans = NULL; + } + + return 0; +} + +void +interleave_decode(INTERLEAVE_CTX *ictx, unsigned char *dst, unsigned char *src) +{ + + int k; + for (k = 0; k < ictx->trans_size; k++) + dst[k] = src[ictx->trans[k]]; +} + diff --git a/gsm-tvoid/src/lib/interleave.h b/gsm-tvoid/src/lib/interleave.h new file mode 100644 index 0000000..b1abf81 --- /dev/null +++ b/gsm-tvoid/src/lib/interleave.h @@ -0,0 +1,18 @@ +/* + * $Id:$ + */ + +#ifndef __GSMSP_INTERLEAVE_H__ +#define __GSMSP_INTERLEAVE_H__ 1 + +typedef struct _interleave_ctx +{ + unsigned short *trans; + int trans_size; +} INTERLEAVE_CTX; + +int interleave_init(INTERLEAVE_CTX *ictx, int size, int block_size); +int interleave_deinit(INTERLEAVE_CTX *ictx); +void interleave_decode(INTERLEAVE_CTX *ictx, unsigned char *dst, unsigned char *src); + +#endif diff --git a/gsm-tvoid/src/lib/sch.c b/gsm-tvoid/src/lib/sch.c new file mode 100644 index 0000000..c01d7bb --- /dev/null +++ b/gsm-tvoid/src/lib/sch.c @@ -0,0 +1,323 @@ +#include "system.h" +#include +#include +#include +#include +#include "burst_types.h" + +/* + * Synchronization channel. + * + * Timeslot Repeat length Frame Number (mod repeat length) + * 0 51 1, 11, 21, 31, 41 + */ + +/* + * Parity (FIRE) for the GSM SCH. + * + * g(x) = x^10 + x^8 + x^6 + x^5 + x^4 + x^2 + 1 + */ +#define DATA_BLOCK_SIZE 25 +#define PARITY_SIZE 10 +#define TAIL_BITS_SIZE 4 +#define PARITY_OUTPUT_SIZE (DATA_BLOCK_SIZE + PARITY_SIZE + TAIL_BITS_SIZE) + +static const unsigned char parity_polynomial[PARITY_SIZE + 1] = { + 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1 +}; + +static const unsigned char parity_remainder[PARITY_SIZE] = { + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 +}; + + +static void parity_encode(unsigned char *d, unsigned char *p) { + + unsigned int i; + unsigned char buf[DATA_BLOCK_SIZE + PARITY_SIZE], *q; + + memcpy(buf, d, DATA_BLOCK_SIZE); + memset(buf + DATA_BLOCK_SIZE, 0, PARITY_SIZE); + + for(q = buf; q < buf + DATA_BLOCK_SIZE; q++) + if(*q) + for(i = 0; i < PARITY_SIZE + 1; i++) + q[i] ^= parity_polynomial[i]; + for(i = 0; i < PARITY_SIZE; i++) + p[i] = !buf[DATA_BLOCK_SIZE + i]; +} + + +static int parity_check(unsigned char *d) { + + unsigned int i; + unsigned char buf[DATA_BLOCK_SIZE + PARITY_SIZE], *q; + + memcpy(buf, d, DATA_BLOCK_SIZE + PARITY_SIZE); + + for(q = buf; q < buf + DATA_BLOCK_SIZE; q++) + if(*q) + for(i = 0; i < PARITY_SIZE + 1; i++) + q[i] ^= parity_polynomial[i]; + return memcmp(buf + DATA_BLOCK_SIZE, parity_remainder, PARITY_SIZE); +} + + +/* + * Convolutional encoding and Viterbi decoding for the GSM SCH. + * (Equivalent to the GSM SACCH.) + * + * G_0 = 1 + x^3 + x^4 + * G_1 = 1 + x + x^3 + x^4 + * + * i.e., + * + * c_{2k} = u_k + u_{k - 3} + u_{k - 4} + * c_{2k + 1} = u_k + u_{k - 1} + u_{k - 3} + u_{k - 4} + */ +#define CONV_INPUT_SIZE PARITY_OUTPUT_SIZE +#define CONV_SIZE (2 * CONV_INPUT_SIZE) +#define K 5 +#define MAX_ERROR (2 * CONV_INPUT_SIZE + 1) + + +/* + * Given the current state and input bit, what are the output bits? + * + * encode[current_state][input_bit] + */ +static const unsigned int encode[1 << (K - 1)][2] = { + {0, 3}, {3, 0}, {3, 0}, {0, 3}, + {0, 3}, {3, 0}, {3, 0}, {0, 3}, + {1, 2}, {2, 1}, {2, 1}, {1, 2}, + {1, 2}, {2, 1}, {2, 1}, {1, 2} +}; + + +/* + * Given the current state and input bit, what is the next state? + * + * next_state[current_state][input_bit] + */ +static const unsigned int next_state[1 << (K - 1)][2] = { + {0, 8}, {0, 8}, {1, 9}, {1, 9}, + {2, 10}, {2, 10}, {3, 11}, {3, 11}, + {4, 12}, {4, 12}, {5, 13}, {5, 13}, + {6, 14}, {6, 14}, {7, 15}, {7, 15} +}; + + +/* + * Given the previous state and the current state, what input bit caused + * the transition? If it is impossible to transition between the two + * states, the value is 2. + * + * prev_next_state[previous_state][current_state] + */ +static const unsigned int prev_next_state[1 << (K - 1)][1 << (K - 1)] = { + { 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2}, + { 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2}, + { 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2}, + { 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2}, + { 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2}, + { 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2}, + { 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2}, + { 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2}, + { 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2}, + { 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2}, + { 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2}, + { 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2}, + { 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2}, + { 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1, 2}, + { 2, 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1}, + { 2, 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 1} +}; + + +static inline unsigned int hamming_distance2(unsigned int w) { + + return (w & 1) + !!(w & 2); +} + + +static void conv_encode(unsigned char *data, unsigned char *output) { + + unsigned int i, state = 0, o; + + // encode data + for(i = 0; i < CONV_INPUT_SIZE; i++) { + o = encode[state][data[i]]; + state = next_state[state][data[i]]; + *output++ = !!(o & 2); + *output++ = o & 1; + } +} + + +static int conv_decode(unsigned char *data, unsigned char *output) { + + int i, t; + unsigned int rdata, state, nstate, b, o, distance, accumulated_error, + min_state, min_error, cur_state; + + unsigned int ae[1 << (K - 1)]; + unsigned int nae[1 << (K - 1)]; // next accumulated error + unsigned int state_history[1 << (K - 1)][CONV_INPUT_SIZE + 1]; + + // initialize accumulated error, assume starting state is 0 + for(i = 0; i < (1 << (K - 1)); i++) + ae[i] = nae[i] = MAX_ERROR; + ae[0] = 0; + + // build trellis + for(t = 0; t < CONV_INPUT_SIZE; t++) { + + // get received data symbol + rdata = (data[2 * t] << 1) | data[2 * t + 1]; + + // for each state + for(state = 0; state < (1 << (K - 1)); state++) { + + // make sure this state is possible + if(ae[state] >= MAX_ERROR) + continue; + + // find all states we lead to + for(b = 0; b < 2; b++) { + + // get next state given input bit b + nstate = next_state[state][b]; + + // find output for this transition + o = encode[state][b]; + + // calculate distance from received data + distance = hamming_distance2(rdata ^ o); + + // choose surviving path + accumulated_error = ae[state] + distance; + if(accumulated_error < nae[nstate]) { + + // save error for surviving state + nae[nstate] = accumulated_error; + + // update state history + state_history[nstate][t + 1] = state; + } + } + } + + // get accumulated error ready for next time slice + for(i = 0; i < (1 << (K - 1)); i++) { + ae[i] = nae[i]; + nae[i] = MAX_ERROR; + } + } + + // the final state is the state with the fewest errors + min_state = (unsigned int)-1; + min_error = MAX_ERROR; + for(i = 0; i < (1 << (K - 1)); i++) { + if(ae[i] < min_error) { + min_state = i; + min_error = ae[i]; + } + } + + // trace the path + cur_state = min_state; + for(t = CONV_INPUT_SIZE; t >= 1; t--) { + min_state = cur_state; + cur_state = state_history[cur_state][t]; // get previous + output[t - 1] = prev_next_state[cur_state][min_state]; + } + + // return the number of errors detected (hard-decision) + return min_error; +} + + +int decode_sch(const unsigned char *buf, int *fn_o, int *bsic_o) { + + int errors, bsic, t1, t2, t3p, t3, fn, tt; + unsigned char data[CONV_SIZE], decoded_data[PARITY_OUTPUT_SIZE]; + + // extract encoded data from synchronization burst + /* buf + 3, 39 bit */ + /* buf + 3 + 39 + 64 = 106, 39 */ + memcpy(data, buf + SB_EDATA_OS_1, SB_EDATA_LEN_1); + memcpy(data + SB_EDATA_LEN_1, buf + SB_EDATA_OS_2, SB_EDATA_LEN_2); + + // Viterbi decode + if(errors = conv_decode(data, decoded_data)) { + // fprintf(stderr, "error: sch: conv_decode (%d)\n", errors); + DEBUGF("ERR: conv_decode %d\n", errors); + return errors; + } + + // check parity + if(parity_check(decoded_data)) { + // fprintf(stderr, "error: sch: parity failed\n"); + DEBUGF("ERR: parity_check failed\n"); + return 1; + } + + // Synchronization channel information, 44.018 page 171. (V7.2.0) + bsic = + (decoded_data[ 7] << 5) | + (decoded_data[ 6] << 4) | + (decoded_data[ 5] << 3) | + (decoded_data[ 4] << 2) | + (decoded_data[ 3] << 1) | + (decoded_data[ 2] << 0); + t1 = + (decoded_data[ 1] << 10) | + (decoded_data[ 0] << 9) | + (decoded_data[15] << 8) | + (decoded_data[14] << 7) | + (decoded_data[13] << 6) | + (decoded_data[12] << 5) | + (decoded_data[11] << 4) | + (decoded_data[10] << 3) | + (decoded_data[ 9] << 2) | + (decoded_data[ 8] << 1) | + (decoded_data[23] << 0); + t2 = + (decoded_data[22] << 4) | + (decoded_data[21] << 3) | + (decoded_data[20] << 2) | + (decoded_data[19] << 1) | + (decoded_data[18] << 0); + t3p = + (decoded_data[17] << 2) | + (decoded_data[16] << 1) | + (decoded_data[24] << 0); + + t3 = 10 * t3p + 1; + + // modulo arithmetic + if(t3 < t2) + tt = (t3 + 26) - t2; + else + tt = (t3 - t2) % 26; + fn = (51 * 26 * t1) + (51 * tt) + t3; + + /* + * BSIC: Base Station Identification Code + * BCC: Base station Color Code + * NCC: Network Color Code + * + * FN: Frame Number + */ + /* + printf("bsic: %x (bcc: %u; ncc: %u)\tFN: %u\n", bsic, bsic & 7, + (bsic >> 3) & 7, fn); + */ + + if(fn_o) + *fn_o = fn; + if(bsic_o) + *bsic_o = bsic; + + return 0; +} diff --git a/gsm-tvoid/src/lib/sch.h b/gsm-tvoid/src/lib/sch.h new file mode 100644 index 0000000..6fd31b8 --- /dev/null +++ b/gsm-tvoid/src/lib/sch.h @@ -0,0 +1,16 @@ + +#ifndef __GSMSTACK_H__ +#define __GSMSTACK_H__ 1 + +#ifdef __cplusplus +extern "C" { +#endif + +int decode_sch(const unsigned char *src, int *fn_o, int *bsic_o); + +#ifdef __cplusplus +} +#endif + +#endif + diff --git a/gsm-tvoid/src/lib/system.h b/gsm-tvoid/src/lib/system.h new file mode 100644 index 0000000..414730a --- /dev/null +++ b/gsm-tvoid/src/lib/system.h @@ -0,0 +1,11 @@ + +#ifndef __GSMTVOID_SYSTEM_H__ +#define __GSMTVOID_SYSTEM_H__ 1 + +#define DEBUGF(a...) { \ + fprintf(stderr, "%s:%d ", __FILE__, __LINE__); \ + fprintf(stderr, a); \ +} while (0) + +#endif + -- cgit v1.2.3