FreeCalypso > hg > gsm-codec-lib
view libgsmefr/d1035pf.c @ 467:ad032051166a
doc: AMR-EFR-hybrid-emu new article
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sun, 12 May 2024 23:54:43 +0000 |
parents | 6ad363f7ea30 |
children |
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/************************************************************************* * * FUNCTION: dec_10i40_35bits() * * PURPOSE: Builds the innovative codevector from the received * index of algebraic codebook. * * See c1035pf.c for more details about the algebraic codebook structure. * *************************************************************************/ #include "gsm_efr.h" #include "typedef.h" #include "namespace.h" #include "basic_op.h" #include "memops.h" #include "no_count.h" #include "codec.h" #define L_CODE 40 /* codevector length */ #define NB_PULSE 10 /* number of pulses */ #define NB_TRACK 5 /* number of track */ void dec_10i40_35bits ( const Word16 index[], /* (i) : index of 10 pulses (sign+position) */ Word16 cod[] /* (o) : algebraic (fixed) codebook excitation */ ) { static const Word16 dgray[8] = {0, 1, 3, 2, 5, 6, 4, 7}; Word16 i, j, pos1, pos2, sign, tmp; Set_zero (cod, L_CODE); /* decode the positions and signs of pulses and build the codeword */ for (j = 0; j < NB_TRACK; j++) { /* compute index i */ tmp = index[j]; move16 (); i = tmp & 7; logic16 (); i = dgray[i]; move16 (); i *= 5; pos1 = i + j; /* position of pulse "j" */ i = shr (tmp, 3) & 1; logic16 (); if (i == 0) { sign = 4096; move16 (); /* +1.0 */ } else { sign = -4096; move16 (); /* -1.0 */ } cod[pos1] = sign; move16 (); /* compute index i */ i = index[add (j, 5)] & 7; logic16 (); i = dgray[i]; move16 (); i *= 5; pos2 = i + j; /* position of pulse "j+5" */ if (pos2 < pos1) { sign = negate (sign); } cod[pos2] = add (cod[pos2], sign); move16 (); } return; }