ref: dfaee703c5704ad796f152e45df0bd4c5d4106b7
dir: /amr-wb/c2t64fx.c/
/*------------------------------------------------------------------------*
* C2T64FX.C *
*------------------------------------------------------------------------*
* Performs algebraic codebook search for 6.60 kbit/s mode *
*------------------------------------------------------------------------*/
/*-----------------------------------------------------------------------*
* Function ACELP_2t64_fx() *
* ~~~~~~~~~~~~~~~~~~~~~~~~~ *
* 12 bits algebraic codebook. *
* 2 tracks x 32 positions per track = 64 samples. *
* *
* 12 bits --> 2 pulses in a frame of 64 samples. *
* *
* All pulses can have two (2) possible amplitudes: +1 or -1. *
* Each pulse can have 32 possible positions. *
*-----------------------------------------------------------------------*/
#include "typedef.h"
#include "basic_op.h"
#include "math_op.h"
#include "acelp.h"
#include "count.h"
#include "cnst.h"
#define NB_TRACK 2
#define STEP 2
#define NB_POS 32
#define MSIZE 1024
void ACELP_2t64_fx(
Word16 dn[], /* (i) <12b : correlation between target x[] and H[] */
Word16 cn[], /* (i) <12b : residual after long term prediction */
Word16 H[], /* (i) Q12: impulse response of weighted synthesis filter */
Word16 code[], /* (o) Q9 : algebraic (fixed) codebook excitation */
Word16 y[], /* (o) Q9 : filtered fixed codebook excitation */
Word16 * index /* (o) : index (12): 5+1+5+1 = 11 bits. */
)
{
Word16 i, j, k, i0, i1, ix, iy, pos, pos2;
Word16 ps, psk, ps1, ps2, alpk, alp1, alp2, sq;
Word16 alp, val, exp, k_cn, k_dn;
Word16 *p0, *p1, *p2, *psign;
Word16 *h, *h_inv, *ptr_h1, *ptr_h2, *ptr_hf;
Word16 sign[L_SUBFR], vec[L_SUBFR], dn2[L_SUBFR];
Word16 h_buf[4 * L_SUBFR];
Word16 rrixix[NB_TRACK][NB_POS];
Word16 rrixiy[MSIZE];
Word32 s, cor;
/*----------------------------------------------------------------*
* Find sign for each pulse position. *
*----------------------------------------------------------------*/
alp = 8192; move16(); /* alp = 2.0 (Q12) */
/* calculate energy for normalization of cn[] and dn[] */
/* set k_cn = 32..32767 (ener_cn = 2^30..256-0) */
s = Dot_product12(cn, cn, L_SUBFR, &exp);
Isqrt_n(&s, &exp);
s = L_shl(s, add(exp, 5)); /* saturation can occur here */
k_cn = round(s);
/* set k_dn = 32..512 (ener_dn = 2^30..2^22) */
s = Dot_product12(dn, dn, L_SUBFR, &exp);
Isqrt_n(&s, &exp);
k_dn = round(L_shl(s, add(exp, 5 + 3))); /* k_dn = 256..4096 */
k_dn = mult_r(alp, k_dn); /* alp in Q12 */
/* mix normalized cn[] and dn[] */
for (i = 0; i < L_SUBFR; i++)
{
s = L_mac(L_mult(k_cn, cn[i]), k_dn, dn[i]);
dn2[i] = extract_h(L_shl(s, 8)); move16();
}
/* set sign according to dn2[] = k_cn*cn[] + k_dn*dn[] */
for (k = 0; k < NB_TRACK; k++)
{
for (i = k; i < L_SUBFR; i += STEP)
{
val = dn[i]; move16();
ps = dn2[i]; move16();
test();
if (ps >= 0)
{
sign[i] = 32767; move16(); /* sign = +1 (Q12) */
vec[i] = -32768; move16();
} else
{
sign[i] = -32768; move16(); /* sign = -1 (Q12) */
vec[i] = 32767; move16();
val = negate(val);
}
dn[i] = val; move16(); /* modify dn[] according to the fixed sign */
}
}
/*------------------------------------------------------------*
* Compute h_inv[i]. *
*------------------------------------------------------------*/
/* impulse response buffer for fast computation */
h = h_buf; move16();
h_inv = h_buf + (2 * L_SUBFR); move16();
for (i = 0; i < L_SUBFR; i++)
{
*h++ = 0; move16();
*h_inv++ = 0; move16();
}
for (i = 0; i < L_SUBFR; i++)
{
h[i] = H[i]; move16();
h_inv[i] = negate(h[i]); move16();
}
/*------------------------------------------------------------*
* Compute rrixix[][] needed for the codebook search. *
* Result is multiplied by 0.5 *
*------------------------------------------------------------*/
/* Init pointers to last position of rrixix[] */
p0 = &rrixix[0][NB_POS - 1]; move16();
p1 = &rrixix[1][NB_POS - 1]; move16();
ptr_h1 = h; move16();
cor = 0x00010000L; move32(); /* for rounding */
for (i = 0; i < NB_POS; i++)
{
move16();move16();
cor = L_mac(cor, *ptr_h1, *ptr_h1);
ptr_h1++;
*p1-- = extract_h(cor); move16();
cor = L_mac(cor, *ptr_h1, *ptr_h1);
ptr_h1++;
*p0-- = extract_h(cor); move16();
}
p0 = rrixix[0]; move16();
p1 = rrixix[1]; move16();
for (i = 0; i < NB_POS; i++)
{
*p0 = shr(*p0, 1); move16();
p0++;
*p1 = shr(*p1, 1); move16();
p1++;
}
/*------------------------------------------------------------*
* Compute rrixiy[][] needed for the codebook search. *
*------------------------------------------------------------*/
pos = MSIZE - 1; move16();
pos2 = MSIZE - 2; move16();
ptr_hf = h + 1; move16();
for (k = 0; k < NB_POS; k++)
{
p1 = &rrixiy[pos]; move16();
p0 = &rrixiy[pos2]; move16();
cor = 0x00008000L; move32(); /* for rounding */
ptr_h1 = h; move16();
ptr_h2 = ptr_hf; move16();
for (i = (Word16) (k + 1); i < NB_POS; i++)
{
cor = L_mac(cor, *ptr_h1, *ptr_h2);
ptr_h1++;
ptr_h2++;
*p1 = extract_h(cor); move16();
cor = L_mac(cor, *ptr_h1, *ptr_h2);
ptr_h1++;
ptr_h2++;
*p0 = extract_h(cor); move16();
p1 -= (NB_POS + 1);
p0 -= (NB_POS + 1);
}
cor = L_mac(cor, *ptr_h1, *ptr_h2);
ptr_h1++;
ptr_h2++;
*p1 = extract_h(cor); move16();
pos -= NB_POS;
pos2--;
ptr_hf += STEP;
}
/*------------------------------------------------------------*
* Modification of rrixiy[][] to take signs into account. *
*------------------------------------------------------------*/
p0 = rrixiy; move16();
for (i = 0; i < L_SUBFR; i += STEP)
{
psign = sign; move16();
test();
if (psign[i] < 0)
{
psign = vec; move16();
}
for (j = 1; j < L_SUBFR; j += STEP)
{
*p0 = mult(*p0, psign[j]); move16();
p0++;
}
}
/*-------------------------------------------------------------------*
* search 2 pulses: *
* ~@~~~~~~~~~~~~~~ *
* 32 pos x 32 pos = 1024 tests (all combinaisons is tested) *
*-------------------------------------------------------------------*/
p0 = rrixix[0]; move16();
p1 = rrixix[1]; move16();
p2 = rrixiy; move16();
psk = -1; move16();
alpk = 1; move16();
ix = 0; move16();
iy = 1; move16();
for (i0 = 0; i0 < L_SUBFR; i0 += STEP)
{
ps1 = dn[i0]; move16();
alp1 = (*p0++); move16();
pos = -1; move16();
for (i1 = 1; i1 < L_SUBFR; i1 += STEP)
{
ps2 = add(ps1, dn[i1]);
alp2 = add(alp1, add(*p1++, *p2++));
sq = mult(ps2, ps2);
s = L_msu(L_mult(alpk, sq), psk, alp2);
test();
if (s > 0)
{
psk = sq; move16();
alpk = alp2; move16();
pos = i1; move16();
}
}
p1 -= NB_POS;
test();
if (pos >= 0)
{
ix = i0; move16();
iy = pos; move16();
}
}
/*-------------------------------------------------------------------*
* Build the codeword, the filtered codeword and index of codevector.*
*-------------------------------------------------------------------*/
for (i = 0; i < L_SUBFR; i++)
{
code[i] = 0; move16();
}
i0 = shr(ix, 1); /* pos of pulse 1 (0..31) */
i1 = shr(iy, 1); /* pos of pulse 2 (0..31) */
test();
if (sign[ix] > 0)
{
code[ix] = 512; move16(); /* codeword in Q9 format */
p0 = h - ix; move16();
} else
{
code[ix] = -512; move16();
i0 += NB_POS; move16();
p0 = h_inv - ix; move16();
}
test();
if (sign[iy] > 0)
{
code[iy] = 512; move16();
p1 = h - iy; move16();
} else
{
code[iy] = -512; move16();
i1 += NB_POS; move16();
p1 = h_inv - iy; move16();
}
*index = add(shl(i0, 6), i1); move16();
for (i = 0; i < L_SUBFR; i++)
{
y[i] = shr_r(add(*p0++, *p1++), 3);move16();
}
return;
}