/* First and second pass at once */
static inline void MLO_Fft_DoPass1 (MLO_Float dest_ptr [], const MLO_Float x_ptr [], int len, const MLO_Int16 br_ptr [])
{
const int qlen = len >> 2;
int coef_index = 0;
do
{
const int ri_0 = br_ptr [coef_index >> 2];
const int ri_1 = ri_0 + 2 * qlen; /* br_ptr [coef_index + 1] */
const int ri_2 = ri_0 + 1 * qlen; /* br_ptr [coef_index + 2] */
const int ri_3 = ri_0 + 3 * qlen; /* br_ptr [coef_index + 3] */
MLO_Float * df2 = dest_ptr + coef_index;
MLO_Float sf_0;
MLO_Float sf_2;
df2 [1] = MLO_Float_Sub (x_ptr [ri_0], x_ptr [ri_1]);
df2 [3] = MLO_Float_Sub (x_ptr [ri_2], x_ptr [ri_3]);
sf_0 = MLO_Float_Add (x_ptr [ri_0], x_ptr [ri_1]);
sf_2 = MLO_Float_Add (x_ptr [ri_2], x_ptr [ri_3]);
df2 [0] = MLO_Float_Add (sf_0, sf_2);
df2 [2] = MLO_Float_Sub (sf_0, sf_2);
coef_index += 4;
}
while (coef_index < len);
}
/* Third pass */
static inline void MLO_Fft_DoPass3 (MLO_Float dest_ptr [], const MLO_Float src_ptr [], int len)
{
const MLO_Float sqrt2_2 = MLO_FLOAT_C (MLO_DEFS_SQRT2 * 0.5);
int coef_index = 0;
do
{
MLO_Float v;
dest_ptr [coef_index ] = MLO_Float_Add (src_ptr [coef_index], src_ptr [coef_index + 4]);
dest_ptr [coef_index + 4] = src_ptr [coef_index] - src_ptr [coef_index + 4];
dest_ptr [coef_index + 2] = src_ptr [coef_index + 2];
dest_ptr [coef_index + 6] = src_ptr [coef_index + 6];
v = MLO_Float_Sub (src_ptr [coef_index + 5], src_ptr [coef_index + 7]);
v = MLO_Float_Mul (v, sqrt2_2);
dest_ptr [coef_index + 1] = MLO_Float_Add (src_ptr [coef_index + 1], v);
dest_ptr [coef_index + 3] = MLO_Float_Sub (src_ptr [coef_index + 1], v);
v = MLO_Float_Add (src_ptr [coef_index + 5], src_ptr [coef_index + 7]);
v = MLO_Float_Mul (v, sqrt2_2);
dest_ptr [coef_index + 5] = MLO_Float_Add (v, src_ptr [coef_index + 3]);
dest_ptr [coef_index + 7] = MLO_Float_Sub (v, src_ptr [coef_index + 3]);
coef_index += 8;
}
while (coef_index < len);
}
/* Other passes */
static inline void MLO_Fft_DoPassN (MLO_Float dest_ptr [], const MLO_Float src_ptr [], int len, int pass)
{
const int dist = 1L << (pass - 2);
const int c1_r = 0;
const int c1_i = dist;
const int c2_r = dist * 2;
const int c2_i = dist * 3;
const int cend = dist * 4;
const int table_step = MLO_FFT_TABLE_LEN_COS >> (pass - 2);
long coef_index = 0;
do
{
const MLO_Float * const sf = src_ptr + coef_index;
MLO_Float * const df = dest_ptr + coef_index;
int i = 1;
/* Extreme coefficients are always real */
df [c1_r] = MLO_Float_Add (sf [c1_r], sf [c2_r]);
df [c2_r] = sf [c1_r] - sf [c2_r];
df [c1_i] = sf [c1_i];
df [c2_i] = sf [c2_i];
/* Others are conjugate complex numbers */
do
{
const MLO_Float c = MLO_Fft_table_cos [ i * table_step];
const MLO_Float s = MLO_Fft_table_cos [(dist - i) * table_step];
const MLO_Float sf_r_i = sf [c1_r + i];
const MLO_Float sf_i_i = sf [c1_i + i];
const MLO_Float v1 = MLO_Float_Sub (
MLO_Float_Mul (sf [c2_r + i], c),
MLO_Float_Mul (sf [c2_i + i], s)
);
MLO_Float v2;
df [c1_r + i] = MLO_Float_Add (sf_r_i, v1);
df [c2_r - i] = MLO_Float_Sub (sf_r_i, v1);
v2 = MLO_Float_Add (
MLO_Float_Mul (sf [c2_r + i], s),
MLO_Float_Mul (sf [c2_i + i], c)
);
df [c2_r + i] = MLO_Float_Add (v2, sf_i_i);
df [cend - i] = MLO_Float_Sub (v2, sf_i_i);
++ i;
}
while (i < dist);
coef_index += cend;
}
while (coef_index < len);
}
static void MLO_Ms_ProcessSfb (MLO_IndivChnStream *ics_l_ptr, MLO_IndivChnStream *ics_r_ptr, int g, int sfb, int win_pos)
{
int sfb_start;
int sfb_len;
int window_group_length;
int win;
MLO_ASSERT (ics_l_ptr != NULL);
MLO_ASSERT (ics_r_ptr != NULL);
MLO_ASSERT (g >= 0);
MLO_ASSERT (g < 8);
MLO_ASSERT (sfb >= 0);
MLO_ASSERT (sfb < ics_r_ptr->ics_info.max_sfb);
MLO_ASSERT (win_pos >= 0);
MLO_ASSERT (win_pos < MLO_DEFS_FRAME_LEN_LONG);
sfb_start = ics_r_ptr->ics_info.swb_offset [sfb];
sfb_len = ics_r_ptr->ics_info.swb_offset [sfb + 1] - sfb_start;
win_pos += sfb_start;
window_group_length = ics_r_ptr->ics_info.window_group_length [g];
for (win = 0; win < window_group_length; ++win)
{
int pos_end = win_pos + sfb_len;
int i;
for (i = win_pos; i < pos_end; ++i)
{
const MLO_Float l = ics_l_ptr->coef_arr [i];
const MLO_Float r = ics_r_ptr->coef_arr [i];
ics_l_ptr->coef_arr [i] = MLO_Float_Add (l, r);
ics_r_ptr->coef_arr [i] = MLO_Float_Sub (l, r);
}
win_pos += MLO_DEFS_FRAME_LEN_SHORT;
}
}
