15e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh/* 25e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische 35e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * Universitaet Berlin. See the accompanying file "COPYRIGHT" for 45e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE. 55e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh */ 65e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 75e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh/* $Header: /tmp_amd/presto/export/kbs/jutta/src/gsm/RCS/preprocess.c,v 1.2 1994/05/10 20:18:45 jutta Exp $ */ 85e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 95e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh#include <stdio.h> 105e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh#include <assert.h> 115e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 125e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh#include "private.h" 135e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 145e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh#include "gsm.h" 155e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh#include "proto.h" 165e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 175e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh/* 4.2.0 .. 4.2.3 PREPROCESSING SECTION 185e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * 195e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * After A-law to linear conversion (or directly from the 205e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * Ato D converter) the following scaling is assumed for 215e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * input to the RPE-LTP algorithm: 225e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * 235e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * in: 0.1.....................12 245e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * S.v.v.v.v.v.v.v.v.v.v.v.v.*.*.* 255e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * 265e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * Where S is the sign bit, v a valid bit, and * a "don't care" bit. 275e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * The original signal is called sop[..] 285e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * 295e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * out: 0.1................... 12 305e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * S.S.v.v.v.v.v.v.v.v.v.v.v.v.0.0 315e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh */ 325e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 335e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 345e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yehvoid Gsm_Preprocess P3((S, s, so), 355e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh struct gsm_state * S, 365e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh word * s, 375e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh word * so ) /* [0..159] IN/OUT */ 385e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh{ 395e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 405e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh word z1 = S->z1; 415e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh longword L_z2 = S->L_z2; 425e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh word mp = S->mp; 435e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 445e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh word s1; 455e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh longword L_s2; 465e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 475e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh longword L_temp; 485e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 495e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh word msp, lsp; 505e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh word SO; 515e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 525e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh longword ltmp; /* for ADD */ 535e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh ulongword utmp; /* for L_ADD */ 545e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 555e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh register int k = 160; 565e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 575e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh while (k--) { 585e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 595e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh /* 4.2.1 Downscaling of the input signal 605e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh */ 615e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh SO = SASR( *s, 3 ) << 2; 625e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh s++; 635e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 645e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh assert (SO >= -0x4000); /* downscaled by */ 655e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh assert (SO <= 0x3FFC); /* previous routine. */ 665e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 675e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 685e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh /* 4.2.2 Offset compensation 695e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * 705e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * This part implements a high-pass filter and requires extended 715e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * arithmetic precision for the recursive part of this filter. 725e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * The input of this procedure is the array so[0...159] and the 735e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh * output the array sof[ 0...159 ]. 745e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh */ 755e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh /* Compute the non-recursive part 765e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh */ 775e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 785e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh s1 = SO - z1; /* s1 = gsm_sub( *so, z1 ); */ 795e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh z1 = SO; 805e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 815e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh assert(s1 != MIN_WORD); 825e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 835e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh /* Compute the recursive part 845e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh */ 855e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh L_s2 = s1; 865e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh L_s2 <<= 15; 875e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 885e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh /* Execution of a 31 bv 16 bits multiplication 895e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh */ 905e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 915e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh msp = SASR( L_z2, 15 ); 925e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh lsp = L_z2-((longword)msp<<15); /* gsm_L_sub(L_z2,(msp<<15)); */ 935e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 945e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh L_s2 += GSM_MULT_R( lsp, 32735 ); 955e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh L_temp = (longword)msp * 32735; /* GSM_L_MULT(msp,32735) >> 1;*/ 965e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh L_z2 = GSM_L_ADD( L_temp, L_s2 ); 975e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 985e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh /* Compute sof[k] with rounding 995e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh */ 1005e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh L_temp = GSM_L_ADD( L_z2, 16384 ); 1015e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 1025e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh /* 4.2.3 Preemphasis 1035e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh */ 1045e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 1055e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh msp = GSM_MULT_R( mp, -28180 ); 1065e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh mp = SASR( L_temp, 15 ); 1075e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh *so++ = GSM_ADD( mp, msp ); 1085e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh } 1095e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh 1105e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh S->z1 = z1; 1115e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh S->L_z2 = L_z2; 1125e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh S->mp = mp; 1135e4516958690b9a1b2c98f88eeecba3edd2dbda4Chia-chi Yeh} 114