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fixed-point: First check-point in alg_quant() conversion

--- a/libcelt/arch.h

+++ b/libcelt/arch.h

@@ -65,6 +65,8 @@

 #define NORM_SCALING 16384.f

 #define NORM_SCALING_1 (1.f/16384.f)

+#define NORM_SHIFT 14

+

 #define ENER_SCALING 16384.f

 #define ENER_SCALING_1 (1.f/16384.f)

--- a/libcelt/vq.c

+++ b/libcelt/vq.c

@@ -138,9 +138,12 @@

    VARDECL(float *yp);

    VARDECL(struct NBest *_nbest);

    VARDECL(struct NBest **nbest);

-   float Rpp=0, Rxp=0;

+   celt_word32_t Rpp=0, Rxp=0;

    int maxL = 1;

    float _alpha = Q15_ONE_1*alpha;

+#ifdef FIXED_POINT

+   int yshift = 14-EC_ILOG(K);

+#endif

    ALLOC(x, N, float);

    ALLOC(p, N, float);

@@ -178,10 +181,12 @@

    for (j=0;j<N;j++)

    {

-      Rpp += p[j]*p[j];

-      Rxp += x[j]*p[j];

+      Rpp = MAC16_16(Rpp, P[j],P[j]);

+      Rxp = MAC16_16(Rxp, X[j],P[j]);

    }

-   if (Rpp>1)

+   Rpp = ROUND(Rpp, NORM_SHIFT);

+   Rxp = ROUND(Rxp, NORM_SHIFT);

+   if (Rpp>NORM_SCALING)

       celt_fatal("Rpp > 1");

    /* We only need to initialise the zero because the first iteration only uses that */

@@ -227,7 +232,7 @@

                float tmp_xy, tmp_yy, tmp_yp;

                float score;

                float g;

-               float s = sign*pulsesAtOnce;

+               float s = SHL16(sign*pulsesAtOnce, yshift);

                /* All pulses at one location must have the same sign. */

                if (iy[m][j]*sign < 0)

@@ -234,15 +239,15 @@

                   continue;

                /* Updating the sums of the new pulse(s) */

-               tmp_xy = xy[m] + s*x[j]               - _alpha*s*p[j]*Rxp;

-               tmp_yy = yy[m] + 2.f*s*y[m][j] + s*s      +s*s*_alpha*_alpha*p[j]*p[j]*Rpp - 2.f*_alpha*s*p[j]*yp[m] - 2.f*s*s*_alpha*p[j]*p[j];

-               tmp_yp = yp[m] + s*p[j]               *(1.f-_alpha*Rpp);

+               tmp_xy = xy[m] + s*X[j]               - _alpha*s*P[j]*Rxp*NORM_SCALING_1;

+               tmp_yy = yy[m] + 2.f*s*y[m][j] + s*s      +s*s*_alpha*_alpha*p[j]*p[j]*Rpp*NORM_SCALING_1 - 2.f*_alpha*s*p[j]*yp[m] - 2.f*s*s*_alpha*p[j]*p[j];

+               tmp_yp = yp[m] + s*p[j]               *(1.f-_alpha*Rpp*NORM_SCALING_1);

                /* Compute the gain such that ||p + g*y|| = 1 */

-               g = (approx_sqrt(tmp_yp*tmp_yp + tmp_yy - tmp_yy*Rpp) - tmp_yp)*approx_inv(tmp_yy);

+               g = (approx_sqrt(tmp_yp*tmp_yp + tmp_yy - tmp_yy*Rpp*NORM_SCALING_1) - tmp_yp)*approx_inv(tmp_yy);

                /* Knowing that gain, what the error: (x-g*y)^2 

                   (result is negated and we discard x^2 because it's constant) */

-               score = 2.f*g*tmp_xy - g*g*tmp_yy;

+               score = 2.f*g*tmp_xy*NORM_SCALING_1 - g*g*tmp_yy;

                if (score>nbest[Lupdate-1]->score)

                {

@@ -282,7 +287,7 @@

          int is;

          float s;

          is = nbest[k]->sign*pulsesAtOnce;

-         s = is;

+         s = SHL16(is, yshift);

          for (n=0;n<N;n++)

             ny[k][n] = y[nbest[k]->orig][n] - _alpha*s*p[nbest[k]->pos]*p[n];

          ny[k][nbest[k]->pos] += s;