layer3.c

VC++视频开发实例集锦(包括“远程视频监控”"语音识别系统"等13个经典例子)

	if (!(modes[sfbi] & I_STEREO))
	  continue;

	is_pos = right_ch->scalefac[sfbi];

	if (is_pos >= 7) {  /* illegal intensity position */
	  modes[sfbi] &= ~I_STEREO;
	  continue;
	}

	for (i = 0; i < n; ++i) {
	  register mad_fixed_t left;

	  left = xr[0][l + i];

	  xr[0][l + i] = mad_f_mul(left, is_table[    is_pos]);
	  xr[1][l + i] = mad_f_mul(left, is_table[6 - is_pos]);
	}
      }
    }
  }

  /* middle/side stereo */

  if (header->mode_extension & MS_STEREO) {
    register mad_fixed_t invsqrt2;

    header->flags |= MAD_FLAG_MS_STEREO;

    invsqrt2 = root_table[3 + -2];

    for (sfbi = l = 0; l < 576; ++sfbi, l += n) {
      n = sfbwidth[sfbi];

      if (modes[sfbi] != MS_STEREO)
	continue;

      for (i = 0; i < n; ++i) {
	register mad_fixed_t m, s;

	m = xr[0][l + i];
	s = xr[1][l + i];

	xr[0][l + i] = mad_f_mul(m + s, invsqrt2);  /* l = (m + s) / sqrt(2) */
	xr[1][l + i] = mad_f_mul(m - s, invsqrt2);  /* r = (m - s) / sqrt(2) */
      }
    }
  }

  return MAD_ERROR_NONE;
}

/*
 * NAME:	III_aliasreduce()
 * DESCRIPTION:	perform frequency line alias reduction
 */
static
void III_aliasreduce(mad_fixed_t xr[576], int lines)
{
  mad_fixed_t const *bound;
  int i;

  bound = &xr[lines];
  for (xr += 18; xr < bound; xr += 18) {
    for (i = 0; i < 8; ++i) {
      register mad_fixed_t a, b;
      register mad_fixed64hi_t hi;
      register mad_fixed64lo_t lo;

      a = xr[-1 - i];
      b = xr[     i];

# if defined(ASO_ZEROCHECK)
      if (a | b) {
# endif
	MAD_F_ML0(hi, lo,  a, cs[i]);
	MAD_F_MLA(hi, lo, -b, ca[i]);

	xr[-1 - i] = MAD_F_MLZ(hi, lo);

	MAD_F_ML0(hi, lo,  b, cs[i]);
	MAD_F_MLA(hi, lo,  a, ca[i]);

	xr[     i] = MAD_F_MLZ(hi, lo);
# if defined(ASO_ZEROCHECK)
      }
# endif
    }
  }
}

# if defined(ASO_IMDCT)
void III_imdct_l(mad_fixed_t const [18], mad_fixed_t [36], unsigned int);
# else
/*
 * NAME:	imdct36
 * DESCRIPTION:	perform X[18]->x[36] IMDCT
 */
static inline
void imdct36(mad_fixed_t const X[18], mad_fixed_t x[36])
{
  mad_fixed_t t0, t1, t2,  t3,  t4,  t5,  t6,  t7;
  mad_fixed_t t8, t9, t10, t11, t12, t13, t14, t15;
  register mad_fixed64hi_t hi;
  register mad_fixed64lo_t lo;

  MAD_F_ML0(hi, lo, X[4],  MAD_F(0x0ec835e8));
  MAD_F_MLA(hi, lo, X[13], MAD_F(0x061f78aa));

  t6 = MAD_F_MLZ(hi, lo);

  MAD_F_MLA(hi, lo, (t14 = X[1] - X[10]), -MAD_F(0x061f78aa));
  MAD_F_MLA(hi, lo, (t15 = X[7] + X[16]), -MAD_F(0x0ec835e8));

  t0 = MAD_F_MLZ(hi, lo);

  MAD_F_MLA(hi, lo, (t8  = X[0] - X[11] - X[12]),  MAD_F(0x0216a2a2));
  MAD_F_MLA(hi, lo, (t9  = X[2] - X[9]  - X[14]),  MAD_F(0x09bd7ca0));
  MAD_F_MLA(hi, lo, (t10 = X[3] - X[8]  - X[15]), -MAD_F(0x0cb19346));
  MAD_F_MLA(hi, lo, (t11 = X[5] - X[6]  - X[17]), -MAD_F(0x0fdcf549));

  x[7]  = MAD_F_MLZ(hi, lo);
  x[10] = -x[7];

  MAD_F_ML0(hi, lo, t8,  -MAD_F(0x0cb19346));
  MAD_F_MLA(hi, lo, t9,   MAD_F(0x0fdcf549));
  MAD_F_MLA(hi, lo, t10,  MAD_F(0x0216a2a2));
  MAD_F_MLA(hi, lo, t11, -MAD_F(0x09bd7ca0));

  x[19] = x[34] = MAD_F_MLZ(hi, lo) - t0;

  t12 = X[0] - X[3] + X[8] - X[11] - X[12] + X[15];
  t13 = X[2] + X[5] - X[6] - X[9]  - X[14] - X[17];

  MAD_F_ML0(hi, lo, t12, -MAD_F(0x0ec835e8));
  MAD_F_MLA(hi, lo, t13,  MAD_F(0x061f78aa));

  x[22] = x[31] = MAD_F_MLZ(hi, lo) + t0;

  MAD_F_ML0(hi, lo, X[1],  -MAD_F(0x09bd7ca0));
  MAD_F_MLA(hi, lo, X[7],   MAD_F(0x0216a2a2));
  MAD_F_MLA(hi, lo, X[10], -MAD_F(0x0fdcf549));
  MAD_F_MLA(hi, lo, X[16],  MAD_F(0x0cb19346));

  t1 = MAD_F_MLZ(hi, lo) + t6;

  MAD_F_ML0(hi, lo, X[0],   MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[2],   MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[3],  -MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[5],  -MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[6],   MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[8],  -MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[9],   MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[11],  MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[14],  MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[15], -MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0f9ee890));

  x[6]  = MAD_F_MLZ(hi, lo) + t1;
  x[11] = -x[6];

  MAD_F_ML0(hi, lo, X[0],  -MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[2],  -MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[3],   MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[5],   MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[6],   MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[8],  -MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[9],  -MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[12], -MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[14],  MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[15],  MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[17],  MAD_F(0x04cfb0e2));

  x[23] = x[30] = MAD_F_MLZ(hi, lo) + t1;

  MAD_F_ML0(hi, lo, X[0],  -MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[2],   MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[3],  -MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[5],   MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[6],   MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[8],  -MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[9],  -MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[11],  MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[14],  MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[15],  MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0acf37ad));

  x[18] = x[35] = MAD_F_MLZ(hi, lo) - t1;

  MAD_F_ML0(hi, lo, X[4],   MAD_F(0x061f78aa));
  MAD_F_MLA(hi, lo, X[13], -MAD_F(0x0ec835e8));

  t7 = MAD_F_MLZ(hi, lo);

  MAD_F_MLA(hi, lo, X[1],  -MAD_F(0x0cb19346));
  MAD_F_MLA(hi, lo, X[7],   MAD_F(0x0fdcf549));
  MAD_F_MLA(hi, lo, X[10],  MAD_F(0x0216a2a2));
  MAD_F_MLA(hi, lo, X[16], -MAD_F(0x09bd7ca0));

  t2 = MAD_F_MLZ(hi, lo);

  MAD_F_MLA(hi, lo, X[0],   MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[2],   MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[3],  -MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[5],   MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[6],  -MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[8],  -MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[9],   MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[12],  MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[14],  MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[15],  MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[17],  MAD_F(0x0f426cb5));

  x[5]  = MAD_F_MLZ(hi, lo);
  x[12] = -x[5];

  MAD_F_ML0(hi, lo, X[0],   MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[2],  -MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[3],   MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[5],  -MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[6],  -MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[8],   MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[9],  -MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[11],  MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[12], -MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[14],  MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[15],  MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0bcbe352));

  x[0]  = MAD_F_MLZ(hi, lo) + t2;
  x[17] = -x[0];

  MAD_F_ML0(hi, lo, X[0],  -MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[2],  -MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[3],  -MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[5],   MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[6],   MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[8],   MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[9],   MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[11], -MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[14], -MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[15], -MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[17], -MAD_F(0x03768962));

  x[24] = x[29] = MAD_F_MLZ(hi, lo) + t2;

  MAD_F_ML0(hi, lo, X[1],  -MAD_F(0x0216a2a2));
  MAD_F_MLA(hi, lo, X[7],  -MAD_F(0x09bd7ca0));
  MAD_F_MLA(hi, lo, X[10],  MAD_F(0x0cb19346));
  MAD_F_MLA(hi, lo, X[16],  MAD_F(0x0fdcf549));

  t3 = MAD_F_MLZ(hi, lo) + t7;

  MAD_F_ML0(hi, lo, X[0],   MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[2],   MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[3],  -MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[5],  -MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[6],   MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[8],   MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[9],  -MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[12],  MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[14],  MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[15], -MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0ffc19fd));

  x[8] = MAD_F_MLZ(hi, lo) + t3;
  x[9] = -x[8];

  MAD_F_ML0(hi, lo, X[0],  -MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[2],   MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[3],   MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[5],  -MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[6],  -MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[8],   MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[9],   MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[11], -MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[14], -MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[15],  MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[17],  MAD_F(0x07635284));

  x[21] = x[32] = MAD_F_MLZ(hi, lo) + t3;

  MAD_F_ML0(hi, lo, X[0],  -MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[2],   MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[3],   MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[5],  -MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[6],  -MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[8],   MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[9],   MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[12],  MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[14],  MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[15], -MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0898c779));

  x[20] = x[33] = MAD_F_MLZ(hi, lo) - t3;

  MAD_F_ML0(hi, lo, t14, -MAD_F(0x0ec835e8));
  MAD_F_MLA(hi, lo, t15,  MAD_F(0x061f78aa));

  t4 = MAD_F_MLZ(hi, lo) - t7;

  MAD_F_ML0(hi, lo, t12, MAD_F(0x061f78aa));
  MAD_F_MLA(hi, lo, t13, MAD_F(0x0ec835e8));

  x[4]  = MAD_F_MLZ(hi, lo) + t4;
  x[13] = -x[4];

  MAD_F_ML0(hi, lo, t8,   MAD_F(0x09bd7ca0));
  MAD_F_MLA(hi, lo, t9,  -MAD_F(0x0216a2a2));
  MAD_F_MLA(hi, lo, t10,  MAD_F(0x0fdcf549));
  MAD_F_MLA(hi, lo, t11, -MAD_F(0x0cb19346));

  x[1]  = MAD_F_MLZ(hi, lo) + t4;
  x[16] = -x[1];

  MAD_F_ML0(hi, lo, t8,  -MAD_F(0x0fdcf549));
  MAD_F_MLA(hi, lo, t9,  -MAD_F(0x0cb19346));
  MAD_F_MLA(hi, lo, t10, -MAD_F(0x09bd7ca0));
  MAD_F_MLA(hi, lo, t11, -MAD_F(0x0216a2a2));

  x[25] = x[28] = MAD_F_MLZ(hi, lo) + t4;

  MAD_F_ML0(hi, lo, X[1],  -MAD_F(0x0fdcf549));
  MAD_F_MLA(hi, lo, X[7],  -MAD_F(0x0cb19346));
  MAD_F_MLA(hi, lo, X[10], -MAD_F(0x09bd7ca0));
  MAD_F_MLA(hi, lo, X[16], -MAD_F(0x0216a2a2));

  t5 = MAD_F_MLZ(hi, lo) - t6;

  MAD_F_ML0(hi, lo, X[0],   MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[2],   MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[3],   MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[5],   MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[6],   MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[8],  -MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[9],   MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[11], -MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[12],  MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[14], -MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[15],  MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[17], -MAD_F(0x0d7e8807));

  x[2]  = MAD_F_MLZ(hi, lo) + t5;
  x[15] = -x[2];

  MAD_F_ML0(hi, lo, X[0],   MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[2],   MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[3],   MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[5],   MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[6],  -MAD_F(0x00b2aa3e));
  MAD_F_MLA(hi, lo, X[8],   MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[9],  -MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[11],  MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[12], -MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[14],  MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[15], -MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[17],  MAD_F(0x0e313245));

  x[3]  = MAD_F_MLZ(hi, lo) + t5;
  x[14] = -x[3];

  MAD_F_ML0(hi, lo, X[0],  -MAD_F(0x0ffc19fd));
  MAD_F_MLA(hi, lo, X[2],  -MAD_F(0x0f9ee890));
  MAD_F_MLA(hi, lo, X[3],  -MAD_F(0x0f426cb5));
  MAD_F_MLA(hi, lo, X[5],  -MAD_F(0x0e313245));
  MAD_F_MLA(hi, lo, X[6],  -MAD_F(0x0d7e8807));
  MAD_F_MLA(hi, lo, X[8],  -MAD_F(0x0bcbe352));
  MAD_F_MLA(hi, lo, X[9],  -MAD_F(0x0acf37ad));
  MAD_F_MLA(hi, lo, X[11], -MAD_F(0x0898c779));
  MAD_F_MLA(hi, lo, X[12], -MAD_F(0x07635284));
  MAD_F_MLA(hi, lo, X[14], -MAD_F(0x04cfb0e2));
  MAD_F_MLA(hi, lo, X[15], -MAD_F(0x03768962));
  MAD_F_MLA(hi, lo, X[17], -MAD_F(0x00b2aa3e));

  x[26] = x[27] = MAD_F_MLZ(hi, lo) + t5;
}

/*
 * NAME:	III_imdct_l()
 * DESCRIPTION:	perform IMDCT and windowing for long blocks
 */
static
void III_imdct_l(mad_fixed_t const X[18], mad_fixed_t z[36],
		 unsigned int block_type)
{
  unsigned int i;

  /* IMDCT */

  imdct36(X, z);

  /* windowing */

  switch (block_type) {
  case 0:  /* normal window */
# if defined(ASO_INTERLEAVE1)
    {
      register mad_fixed_t tmp1, tmp2;

      tmp1 = window_l[0];
      tmp2 = window_l[1];

      for (i = 0; i < 34; i += 2) {
	z[i + 0] = mad_f_mul(z[i + 0], tmp1);
	tmp1 = window_l[i + 2];
	z[i + 1] = mad_f_mul(z[i + 1], tmp2);
	tmp2 = window_l[i + 3];
      }

      z[34] = mad_f_mul(z[34], tmp1);
      z[35] = mad_f_mul(z[35], tmp2);
    }
# elif defined(ASO_INTERLEAVE2)
    {
      register mad_fixed_t tmp1, tmp2;

      tmp1 = z[0];
      tmp2 = window_l[0];

      for (i = 0; i < 35; ++i) {
	z[i] = mad_f_mul(tmp1, tmp2);
	tmp1 = z[i + 1];
	tmp2 = window_l[i + 1];
      }

      z[35] = mad_f_mul(tmp1, tmp2);
    }
# elif 1
    for (i = 0; i < 36; i += 4) {
      z[i + 0] = mad_f_mul(z[i + 0], window_l[i + 0]);
      z[i + 1] = mad_f_mul(z[i + 1], window_l[i + 1]);
      z[i + 2] = mad_f_mul(z[i + 2], window_l[i + 2]);
      z[i + 3] = mad_f_mul(z[i + 3], window_l[i + 3]);
    }
# else
    for (i =  0; i < 36; ++i) z[i] = mad_f_mul(z[i], window_l[i]);
# endif
    break;

  case 1:  /* start block */
    for (i =  0; i < 18; ++i) z[i] = mad_f_mul(z[i], window_l[i]);
    /*  (i = 18; i < 24; ++i) z[i] unchanged */
    for (i = 24; i < 30; ++i) z[i] = mad_f_mul(z[i], window_s[i - 18]);
    for (i = 30; i < 36; ++i) z[i] = 0;
    break;

  case 3:  /* stop block */
    for (i =  0; i <  6; ++i) z[i] = 0;
    for (i =  6; i < 12; ++i) z[i] = mad_f_mul(z[i], window_s[i - 6]);
    /*  (i = 12; i < 18; ++i) z[i] unchanged */
    for (i = 18; i < 36; ++i) z[i] = mad_f_mul(z[i], window_l[i]);
    break;
  }
}
# endif  /* ASO_IMDCT */

/*
 * NAME:	III_imdct_s()
 * DESCRIPTION:	perform IMDCT and windowing for short blocks
 */
static
void III_imdct_s(mad_fixed_t const X[18], mad_fixed_t z[36])
{
  mad_fixed_t y[36], *yptr;
  mad_fixed_t const *wptr;
  int w, i;
  register mad_fixed64hi_t hi;
  register mad_fixed64lo_t lo;

  /* IMDCT */

  yptr = &y[0];

  for (w = 0; w < 3; ++w) {
    register mad_fixed_t const (*s)[6];

    s = imdct_s;

    for (i = 0; i < 3; ++i) {
      MAD_F_ML0(hi, lo, X[0], (*s)[0]);
      MAD_F_MLA(hi, lo, X[1], (*s)[1]);