+++ /dev/null
-/*
- * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
- * Universitaet Berlin. See the accompanying file "COPYRIGHT" for
- * details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
- */
-
-#include <stdio.h>
-#include <assert.h>
-
-#include "gsm610_priv.h"
-
-/*
- * 4.2.4 .. 4.2.7 LPC ANALYSIS SECTION
- */
-
-/* 4.2.4 */
-
-
-static void Autocorrelation (
- word * s, /* [0..159] IN/OUT */
- longword * L_ACF) /* [0..8] OUT */
-/*
- * The goal is to compute the array L_ACF[k]. The signal s[i] must
- * be scaled in order to avoid an overflow situation.
- */
-{
- register int k, i;
-
- word temp, smax, scalauto;
-
-#ifdef USE_FLOAT_MUL
- float float_s[160];
-#endif
-
- /* Dynamic scaling of the array s[0..159]
- */
-
- /* Search for the maximum.
- */
- smax = 0;
- for (k = 0; k <= 159; k++) {
- temp = GSM_ABS( s[k] );
- if (temp > smax) smax = temp;
- }
-
- /* Computation of the scaling factor.
- */
- if (smax == 0) scalauto = 0;
- else {
- assert(smax > 0);
- scalauto = 4 - gsm_norm( (longword)smax << 16 );/* sub(4,..) */
- }
-
- /* Scaling of the array s[0...159]
- */
-
- if (scalauto > 0) {
-
-# ifdef USE_FLOAT_MUL
-# define SCALE(n) \
- case n: for (k = 0; k <= 159; k++) \
- float_s[k] = (float) \
- (s[k] = GSM_MULT_R(s[k], 16384 >> (n-1)));\
- break;
-# else
-# define SCALE(n) \
- case n: for (k = 0; k <= 159; k++) \
- s[k] = GSM_MULT_R( s[k], 16384 >> (n-1) );\
- break;
-# endif /* USE_FLOAT_MUL */
-
- switch (scalauto) {
- SCALE(1)
- SCALE(2)
- SCALE(3)
- SCALE(4)
- }
-# undef SCALE
- }
-# ifdef USE_FLOAT_MUL
- else for (k = 0; k <= 159; k++) float_s[k] = (float) s[k];
-# endif
-
- /* Compute the L_ACF[..].
- */
- {
-# ifdef USE_FLOAT_MUL
- register float * sp = float_s;
- register float sl = *sp;
-
-# define STEP(k) L_ACF[k] += (longword)(sl * sp[ -(k) ]);
-# else
- word * sp = s;
- word sl = *sp;
-
-# define STEP(k) L_ACF[k] += ((longword)sl * sp[ -(k) ]);
-# endif
-
-# define NEXTI sl = *++sp
-
-
- for (k = 9; k--; L_ACF[k] = 0) ;
-
- STEP (0);
- NEXTI;
- STEP(0); STEP(1);
- NEXTI;
- STEP(0); STEP(1); STEP(2);
- NEXTI;
- STEP(0); STEP(1); STEP(2); STEP(3);
- NEXTI;
- STEP(0); STEP(1); STEP(2); STEP(3); STEP(4);
- NEXTI;
- STEP(0); STEP(1); STEP(2); STEP(3); STEP(4); STEP(5);
- NEXTI;
- STEP(0); STEP(1); STEP(2); STEP(3); STEP(4); STEP(5); STEP(6);
- NEXTI;
- STEP(0); STEP(1); STEP(2); STEP(3); STEP(4); STEP(5); STEP(6); STEP(7);
-
- for (i = 8; i <= 159; i++) {
-
- NEXTI;
-
- STEP(0);
- STEP(1); STEP(2); STEP(3); STEP(4);
- STEP(5); STEP(6); STEP(7); STEP(8);
- }
-
- for (k = 9; k--; L_ACF[k] <<= 1) ;
-
- }
- /* Rescaling of the array s[0..159]
- */
- if (scalauto > 0) {
- assert(scalauto <= 4);
- for (k = 160; k--; *s++ <<= scalauto) ;
- }
-}
-
-#if defined(USE_FLOAT_MUL) && defined(FAST)
-
-static void Fast_Autocorrelation (
- word * s, /* [0..159] IN/OUT */
- longword * L_ACF) /* [0..8] OUT */
-{
- register int k, i;
- float f_L_ACF[9];
- float scale;
-
- float s_f[160];
- register float *sf = s_f;
-
- for (i = 0; i < 160; ++i) sf[i] = s[i];
- for (k = 0; k <= 8; k++) {
- register float L_temp2 = 0;
- register float *sfl = sf - k;
- for (i = k; i < 160; ++i) L_temp2 += sf[i] * sfl[i];
- f_L_ACF[k] = L_temp2;
- }
- scale = MAX_LONGWORD / f_L_ACF[0];
-
- for (k = 0; k <= 8; k++) {
- L_ACF[k] = f_L_ACF[k] * scale;
- }
-}
-#endif /* defined (USE_FLOAT_MUL) && defined (FAST) */
-
-/* 4.2.5 */
-
-static void Reflection_coefficients (
- longword * L_ACF, /* 0...8 IN */
- register word * r /* 0...7 OUT */
-)
-{
- register int i, m, n;
- register word temp;
- word ACF[9]; /* 0..8 */
- word P[ 9]; /* 0..8 */
- word K[ 9]; /* 2..8 */
-
- /* Schur recursion with 16 bits arithmetic.
- */
-
- if (L_ACF[0] == 0) {
- for (i = 8; i--; *r++ = 0) ;
- return;
- }
-
- assert( L_ACF[0] != 0 );
- temp = gsm_norm( L_ACF[0] );
-
- assert(temp >= 0 && temp < 32);
-
- /* ? overflow ? */
- for (i = 0; i <= 8; i++) ACF[i] = SASR_L( L_ACF[i] << temp, 16 );
-
- /* Initialize array P[..] and K[..] for the recursion.
- */
-
- for (i = 1; i <= 7; i++) K[ i ] = ACF[ i ];
- for (i = 0; i <= 8; i++) P[ i ] = ACF[ i ];
-
- /* Compute reflection coefficients
- */
- for (n = 1; n <= 8; n++, r++) {
-
- temp = P[1];
- temp = GSM_ABS(temp);
- if (P[0] < temp) {
- for (i = n; i <= 8; i++) *r++ = 0;
- return;
- }
-
- *r = gsm_div( temp, P[0] );
-
- assert(*r >= 0);
- if (P[1] > 0) *r = -*r; /* r[n] = sub(0, r[n]) */
- assert (*r != MIN_WORD);
- if (n == 8) return;
-
- /* Schur recursion
- */
- temp = GSM_MULT_R( P[1], *r );
- P[0] = GSM_ADD( P[0], temp );
-
- for (m = 1; m <= 8 - n; m++) {
- temp = GSM_MULT_R( K[ m ], *r );
- P[m] = GSM_ADD( P[ m+1 ], temp );
-
- temp = GSM_MULT_R( P[ m+1 ], *r );
- K[m] = GSM_ADD( K[ m ], temp );
- }
- }
-}
-
-/* 4.2.6 */
-
-static void Transformation_to_Log_Area_Ratios (
- register word * r /* 0..7 IN/OUT */
-)
-/*
- * The following scaling for r[..] and LAR[..] has been used:
- *
- * r[..] = integer( real_r[..]*32768. ); -1 <= real_r < 1.
- * LAR[..] = integer( real_LAR[..] * 16384 );
- * with -1.625 <= real_LAR <= 1.625
- */
-{
- register word temp;
- register int i;
-
-
- /* Computation of the LAR[0..7] from the r[0..7]
- */
- for (i = 1; i <= 8; i++, r++) {
-
- temp = *r;
- temp = GSM_ABS(temp);
- assert(temp >= 0);
-
- if (temp < 22118) {
- temp >>= 1;
- } else if (temp < 31130) {
- assert( temp >= 11059 );
- temp -= 11059;
- } else {
- assert( temp >= 26112 );
- temp -= 26112;
- temp <<= 2;
- }
-
- *r = *r < 0 ? -temp : temp;
- assert( *r != MIN_WORD );
- }
-}
-
-/* 4.2.7 */
-
-static void Quantization_and_coding (
- register word * LAR /* [0..7] IN/OUT */
-)
-{
- register word temp;
-
- /* This procedure needs four tables; the following equations
- * give the optimum scaling for the constants:
- *
- * A[0..7] = integer( real_A[0..7] * 1024 )
- * B[0..7] = integer( real_B[0..7] * 512 )
- * MAC[0..7] = maximum of the LARc[0..7]
- * MIC[0..7] = minimum of the LARc[0..7]
- */
-
-# undef STEP
-# define STEP( A, B, MAC, MIC ) \
- temp = GSM_MULT( A, *LAR ); \
- temp = GSM_ADD( temp, B ); \
- temp = GSM_ADD( temp, 256 ); \
- temp = SASR_W( temp, 9 ); \
- *LAR = temp>MAC ? MAC - MIC : (temp<MIC ? 0 : temp - MIC); \
- LAR++;
-
- STEP( 20480, 0, 31, -32 );
- STEP( 20480, 0, 31, -32 );
- STEP( 20480, 2048, 15, -16 );
- STEP( 20480, -2560, 15, -16 );
-
- STEP( 13964, 94, 7, -8 );
- STEP( 15360, -1792, 7, -8 );
- STEP( 8534, -341, 3, -4 );
- STEP( 9036, -1144, 3, -4 );
-
-# undef STEP
-}
-
-void Gsm_LPC_Analysis (
- struct gsm_state *S,
- word * s, /* 0..159 signals IN/OUT */
- word * LARc) /* 0..7 LARc's OUT */
-{
- longword L_ACF[9];
-
-#if defined(USE_FLOAT_MUL) && defined(FAST)
- if (S->fast) Fast_Autocorrelation (s, L_ACF );
- else
-#endif
- Autocorrelation (s, L_ACF );
- Reflection_coefficients (L_ACF, LARc );
- Transformation_to_Log_Area_Ratios (LARc);
- Quantization_and_coding (LARc);
-}
projects / Faustine.git / blobdiff
