FreeCalypso > hg > gsm-codec-lib
view libtwamr/a_refl.c @ 351:97c699f40ab3
libtwamr: generate namespace.h from namespace.list
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sun, 05 May 2024 20:34:55 +0000 |
parents | 07f936338de1 |
children |
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/* ******************************************************************************** * * GSM AMR-NB speech codec R98 Version 7.6.0 December 12, 2001 * R99 Version 3.3.0 * REL-4 Version 4.1.0 * ******************************************************************************** * * File : a_refl.c * Purpose : Convert from direct form coefficients to * reflection coefficients * ******************************************************************************** */ /* ******************************************************************************** * MODULE INCLUDE FILE AND VERSION ID ******************************************************************************** */ #include "namespace.h" #include "a_refl.h" /* ******************************************************************************** * INCLUDE FILES ******************************************************************************** */ #include "typedef.h" #include "basic_op.h" #include "oper_32b.h" #include "no_count.h" #include "cnst.h" /* ******************************************************************************** * LOCAL VARIABLES AND TABLES ******************************************************************************** */ /* ******************************************************************************** * PUBLIC PROGRAM CODE ******************************************************************************** */ /* ************************************************************************** * * Function : A_Refl * ************************************************************************** */ void A_Refl( Word16 a[], /* i : Directform coefficients */ Word16 refl[] /* o : Reflection coefficients */ ) { /* local variables */ Word16 i,j; Word16 aState[M]; Word16 bState[M]; Word16 normShift; Word16 normProd; Word32 L_acc; Word16 scale; Word32 L_temp; Word16 temp; Word16 mult; /* initialize states */ for (i = 0; i < M; i++) { aState[i] = a[i]; move16 (); } /* backward Levinson recursion */ for (i = M-1; i >= 0; i--) { if (sub(abs_s(aState[i]), 4096) >= 0) { goto ExitRefl; } refl[i] = shl(aState[i], 3); L_temp = L_mult(refl[i], refl[i]); L_acc = L_sub(MAX_32, L_temp); normShift = norm_l(L_acc); scale = sub(15, normShift); L_acc = L_shl(L_acc, normShift); normProd = round(L_acc); mult = div_s(16384, normProd); for (j = 0; j < i; j++) { L_acc = L_deposit_h(aState[j]); L_acc = L_msu(L_acc, refl[i], aState[i-j-1]); temp = round(L_acc); L_temp = L_mult(mult, temp); L_temp = L_shr_r(L_temp, scale); if (L_sub(L_abs(L_temp), 32767) > 0) { goto ExitRefl; } bState[j] = extract_l(L_temp); } for (j = 0; j < i; j++) { aState[j] = bState[j]; move16 (); } } return; ExitRefl: for (i = 0; i < M; i++) { refl[i] = 0; move16 (); } }