FreeCalypso > hg > gsm-codec-lib
diff libgsmefr/d1035pf.c @ 53:49dd1ac8e75b
libgsmefr: import most *.c files from ETSI source
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Fri, 25 Nov 2022 16:18:21 +0000 |
parents | |
children | d273a77d5523 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libgsmefr/d1035pf.c Fri Nov 25 16:18:21 2022 +0000 @@ -0,0 +1,76 @@ +/************************************************************************* + * + * 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 "typedef.h" +#include "basic_op.h" +#include "count.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 ( + 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; + + for (i = 0; i < L_CODE; i++) + { + cod[i] = 0; move16 (); + } + + /* 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 = extract_l (L_shr (L_mult (i, 5), 1)); + pos1 = add (i, j); /* position of pulse "j" */ + + i = shr (tmp, 3) & 1; logic16 (); + test (); + 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 = extract_l (L_shr (L_mult (i, 5), 1)); + + pos2 = add (i, j); /* position of pulse "j+5" */ + + test (); + if (sub (pos2, pos1) < 0) + { + sign = negate (sign); + } + cod[pos2] = add (cod[pos2], sign); move16 (); + } + + return; +}