INLINE void Coefficients_13_26(gsmword * LARpp_j_1, gsmword * LARpp_j, gsmword * LARp)
{
int i;
for(i = 1; i <= 8; i++, LARpp_j_1++, LARpp_j++, LARp++)
*LARp = SASR( *LARpp_j_1, 1) + SASR( *LARpp_j, 1 );
}
INLINE void Coefficients_27_39(gsmword * LARpp_j_1, gsmword * LARpp_j, gsmword * LARp)
{
int i;
for(i = 1; i <= 8; i++, LARpp_j_1++, LARpp_j++, LARp++)
{
*LARp = (gsmword)(SASR( *LARpp_j_1, 2 ) + SASR( *LARpp_j, 2 ));
*LARp += (gsmword)SASR( *LARpp_j, 1 );
}
}
static void APCM_quantization_xmaxc_to_exp_mant (
word xmaxc, /* IN */
word * exp_out, /* OUT */
word * mant_out ) /* OUT */
{
word exp, mant;
/* Compute exponent and mantissa of the decoded version of xmaxc
*/
exp = 0;
if (xmaxc > 15) exp = SASR(xmaxc, 3) - 1;
mant = xmaxc - (exp << 3);
if (mant == 0) {
exp = -4;
mant = 7;
}
else {
while (mant <= 7) {
mant = mant << 1 | 1;
exp--;
}
mant -= 8;
}
assert( exp >= -4 && exp <= 6 );
assert( mant >= 0 && mant <= 7 );
*exp_out = exp;
*mant_out = mant;
}
static void APCM_quantization_xmaxc_to_exp_mant(gsmword xmaxc, gsmword *exp_out,
gsmword *mant_out)
{
gsmword exp, mant;
exp = 0;
if(xmaxc > 15)
exp = (gsmword)(SASR(xmaxc, 3) - 1);
mant = (gsmword)(xmaxc - SASL( exp, 3 ));
if(mant == 0)
{
exp = -4;
mant = 7;
}
else
{
while(mant <= 7)
{
mant = (gsmword)(SASL(mant, 1) | 1);
exp--;
}
mant -= 8;
}
*exp_out = exp;
*mant_out = mant;
}
static void LARp_to_rp(gsmword * LARp)
{
int i;
gsmword temp;
for (i = 1; i <= 8; i++, LARp++)
{
if (*LARp < 0)
{
temp = (gsmword)GSM_ABS( *LARp );
*LARp = (gsmword)(- ((temp < 11059) ? SASL( temp, 1 )
: ((temp < 20070) ? temp + 11059
: ( SASR( temp, 2 ) + 26112 ))));
}
else
{
temp = *LARp;
*LARp = (gsmword)((temp < 11059) ? SASL( temp, 1 )
: ((temp < 20070) ? temp + 11059
: ( SASR( temp, 2 ) + 26112 )));
}
}
}
static void APCM_inverse_quantization(gsmword *xMc, gsmword mant, gsmword exp, gsmword *xMp)
{
int i;
gsmword temp, temp1, temp2, temp3;
longword ltmp;
temp1 = gsm_FACd[ mant ]; /* see 4.2-15 for mant */
temp2 = (gsmword)GSM_SUB( 6, exp ); /* see 4.2-15 for exp */
temp3 = (gsmword)SASL( 1, GSM_SUB( temp2, 1 ));
for(i = 13; i--;)
{
temp = (gsmword)(SASL(*xMc++, 1) - 7); /* restore sign */
temp = (gsmword)SASL(temp, 12); /* 16 bit signed */
temp = (gsmword)GSM_MULT_R( temp1, temp );
temp = (gsmword)GSM_ADD( temp, temp3 );
*xMp++ = (gsmword)SASR( temp, temp2 );
}
}
static void Cut_Calculation_of_the_LTP_parameters (
struct gsm_state * st,
register int16_t * d, /* [0..39] IN */
register int16_t * dp, /* [-120..-1] IN */
int16_t * bc_out, /* OUT */
int16_t * Nc_out /* OUT */)
{
register int k, lambda ;
int16_t Nc, bc ;
int16_t wt [40] ;
int32_t L_result ;
int32_t L_max, L_power ;
int16_t R, S, dmax, scal, best_k ;
int16_t ltp_cut ;
register int16_t temp, wt_k ;
/* Search of the optimum scaling of d [0..39]. */
dmax = 0 ;
for (k = 0 ; k <= 39 ; k++)
{ temp = d [k] ;
temp = GSM_ABS (temp) ;
if (temp > dmax)
{ dmax = temp ;
best_k = k ;
}
}
temp = 0 ;
if (dmax == 0)
scal = 0 ;
else
{ assert (dmax > 0) ;
temp = gsm_norm ((int32_t) dmax << 16) ;
}
if (temp > 6) scal = 0 ;
else scal = 6 - temp ;
assert (scal >= 0) ;
/* Search for the maximum cross-correlation and coding of the LTP lag
*/
L_max = 0 ;
Nc = 40 ; /* index for the maximum cross-correlation */
wt_k = SASR_W (d [best_k], scal) ;
for (lambda = 40 ; lambda <= 120 ; lambda++)
{ L_result = (int32_t) wt_k * dp [best_k - lambda] ;
if (L_result > L_max)
{ Nc = lambda ;
L_max = L_result ;
}
}
*Nc_out = Nc ;
L_max <<= 1 ;
/* Rescaling of L_max
*/
assert (scal <= 100 && scal >= -100) ;
L_max = L_max >> (6 - scal) ; /* sub (6, scal) */
assert (Nc <= 120 && Nc >= 40) ;
/* Compute the power of the reconstructed short term residual
* signal dp [..]
*/
L_power = 0 ;
for (k = 0 ; k <= 39 ; k++)
{ register int32_t L_temp ;
L_temp = SASR_W (dp [k - Nc], 3) ;
L_power += L_temp * L_temp ;
}
L_power <<= 1 ; /* from L_MULT */
/* Normalization of L_max and L_power */
if (L_max <= 0)
{ *bc_out = 0 ;
return ;
}
if (L_max >= L_power)
{ *bc_out = 3 ;
return ;
}
temp = gsm_norm (L_power) ;
R = SASR (L_max << temp, 16) ;
S = SASR (L_power << temp, 16) ;
/* Coding of the LTP gain
*/
/* Table 4.3a must be used to obtain the level DLB [i] for the
* quantization of the LTP gain b to get the coded version bc.
*/
for (bc = 0 ; bc <= 2 ; bc++) if (R <= gsm_mult (S, gsm_DLB [bc])) break ;
*bc_out = bc ;
}
static void Cut_Calculation_of_the_LTP_parameters (
struct gsm_state * st, /* IN */
register int16_t * d, /* [0..39] IN */
register int16_t * dp, /* [-120..-1] IN */
int16_t * bc_out, /* OUT */
int16_t * Nc_out /* OUT */)
{
register int k, lambda ;
int16_t Nc, bc ;
int16_t ltp_cut ;
float wt_float [40] ;
float dp_float_base [120], * dp_float = dp_float_base + 120 ;
int32_t L_max, L_power ;
int16_t R, S, dmax, scal ;
register int16_t temp ;
/* Search of the optimum scaling of d [0..39].
*/
dmax = 0 ;
for (k = 0 ; k <= 39 ; k++)
{ temp = d [k] ;
temp = GSM_ABS (temp) ;
if (temp > dmax) dmax = temp ;
}
temp = 0 ;
if (dmax == 0) scal = 0 ;
else
{ assert (dmax > 0) ;
temp = gsm_norm ((int32_t) dmax << 16) ;
}
if (temp > 6) scal = 0 ;
else scal = 6 - temp ;
assert (scal >= 0) ;
ltp_cut = (int32_t) SASR_W (dmax, scal) * st->ltp_cut / 100 ;
/* Initialization of a working array wt */
for (k = 0 ; k < 40 ; k++)
{ register int16_t w = SASR_W (d [k], scal) ;
if (w < 0 ? w > -ltp_cut : w < ltp_cut)
wt_float [k] = 0.0 ;
else
wt_float [k] = w ;
}
for (k = -120 ; k < 0 ; k++) dp_float [k] = dp [k] ;
/* Search for the maximum cross-correlation and coding of the LTP lag
*/
L_max = 0 ;
Nc = 40 ; /* index for the maximum cross-correlation */
for (lambda = 40 ; lambda <= 120 ; lambda += 9)
{ /* Calculate L_result for l = lambda .. lambda + 9. */
register float *lp = dp_float - lambda ;
register float W ;
register float a = lp [-8], b = lp [-7], c = lp [-6],
d = lp [-5], e = lp [-4], f = lp [-3],
g = lp [-2], h = lp [-1] ;
register float E ;
register float S0 = 0, S1 = 0, S2 = 0, S3 = 0, S4 = 0,
S5 = 0, S6 = 0, S7 = 0, S8 = 0 ;
# undef STEP
# define STEP(K, a, b, c, d, e, f, g, h) \
if ((W = wt_float [K]) != 0.0) { \
E = W * a ; S8 += E ; \
E = W * b ; S7 += E ; \
E = W * c ; S6 += E ; \
E = W * d ; S5 += E ; \
E = W * e ; S4 += E ; \
E = W * f ; S3 += E ; \
E = W * g ; S2 += E ; \
E = W * h ; S1 += E ; \
a = lp [K] ; \
E = W * a ; S0 += E ; } else (a = lp [K])
# define STEP_A(K) STEP (K, a, b, c, d, e, f, g, h)
# define STEP_B(K) STEP (K, b, c, d, e, f, g, h, a)
# define STEP_C(K) STEP (K, c, d, e, f, g, h, a, b)
# define STEP_D(K) STEP (K, d, e, f, g, h, a, b, c)
# define STEP_E(K) STEP (K, e, f, g, h, a, b, c, d)
# define STEP_F(K) STEP (K, f, g, h, a, b, c, d, e)
# define STEP_G(K) STEP (K, g, h, a, b, c, d, e, f)
# define STEP_H(K) STEP (K, h, a, b, c, d, e, f, g)
STEP_A (0) ; STEP_B (1) ; STEP_C (2) ; STEP_D (3) ;
STEP_E (4) ; STEP_F (5) ; STEP_G (6) ; STEP_H (7) ;
STEP_A (8) ; STEP_B (9) ; STEP_C (10) ; STEP_D (11) ;
STEP_E (12) ; STEP_F (13) ; STEP_G (14) ; STEP_H (15) ;
STEP_A (16) ; STEP_B (17) ; STEP_C (18) ; STEP_D (19) ;
STEP_E (20) ; STEP_F (21) ; STEP_G (22) ; STEP_H (23) ;
STEP_A (24) ; STEP_B (25) ; STEP_C (26) ; STEP_D (27) ;
STEP_E (28) ; STEP_F (29) ; STEP_G (30) ; STEP_H (31) ;
STEP_A (32) ; STEP_B (33) ; STEP_C (34) ; STEP_D (35) ;
STEP_E (36) ; STEP_F (37) ; STEP_G (38) ; STEP_H (39) ;
# undef STEP_A
# undef STEP_B
# undef STEP_C
# undef STEP_D
# undef STEP_E
# undef STEP_F
# undef STEP_G
# undef STEP_H
if (S0 > L_max) { L_max = S0 ; Nc = lambda ; }
if (S1 > L_max) { L_max = S1 ; Nc = lambda + 1 ; }
if (S2 > L_max) { L_max = S2 ; Nc = lambda + 2 ; }
if (S3 > L_max) { L_max = S3 ; Nc = lambda + 3 ; }
if (S4 > L_max) { L_max = S4 ; Nc = lambda + 4 ; }
if (S5 > L_max) { L_max = S5 ; Nc = lambda + 5 ; }
if (S6 > L_max) { L_max = S6 ; Nc = lambda + 6 ; }
if (S7 > L_max) { L_max = S7 ; Nc = lambda + 7 ; }
if (S8 > L_max) { L_max = S8 ; Nc = lambda + 8 ; }
}
*Nc_out = Nc ;
L_max <<= 1 ;
/* Rescaling of L_max
*/
assert (scal <= 100 && scal >= -100) ;
L_max = L_max >> (6 - scal) ; /* sub (6, scal) */
assert (Nc <= 120 && Nc >= 40) ;
/* Compute the power of the reconstructed short term residual
* signal dp [..]
*/
L_power = 0 ;
for (k = 0 ; k <= 39 ; k++)
{ register int32_t L_temp ;
L_temp = SASR_W (dp [k - Nc], 3) ;
L_power += L_temp * L_temp ;
}
L_power <<= 1 ; /* from L_MULT */
/* Normalization of L_max and L_power
*/
if (L_max <= 0)
{ *bc_out = 0 ;
return ;
}
if (L_max >= L_power)
{ *bc_out = 3 ;
return ;
}
temp = gsm_norm (L_power) ;
R = SASR (L_max << temp, 16) ;
S = SASR (L_power << temp, 16) ;
/* Coding of the LTP gain
*/
/* Table 4.3a must be used to obtain the level DLB [i] for the
* quantization of the LTP gain b to get the coded version bc.
*/
for (bc = 0 ; bc <= 2 ; bc++) if (R <= gsm_mult (S, gsm_DLB [bc])) break ;
*bc_out = bc ;
}
static void APCM_quantization (
word * xM, /* [0..12] IN */
word * xMc, /* [0..12] OUT */
word * mant_out, /* OUT */
word * exp_out, /* OUT */
word * xmaxc_out /* OUT */
)
{
int i, itest;
word xmax, xmaxc, temp, temp1, temp2;
word exp, mant;
/* Find the maximum absolute value xmax of xM[0..12].
*/
xmax = 0;
for (i = 0; i <= 12; i++) {
temp = xM[i];
temp = GSM_ABS(temp);
if (temp > xmax) xmax = temp;
}
/* Qantizing and coding of xmax to get xmaxc.
*/
exp = 0;
temp = SASR( xmax, 9 );
itest = 0;
for (i = 0; i <= 5; i++) {
itest |= (temp <= 0);
temp = SASR( temp, 1 );
assert(exp <= 5);
if (itest == 0) exp++; /* exp = add (exp, 1) */
}
assert(exp <= 6 && exp >= 0);
temp = exp + 5;
assert(temp <= 11 && temp >= 0);
xmaxc = gsm_add( SASR(xmax, temp), exp << 3 );
/* Quantizing and coding of the xM[0..12] RPE sequence
* to get the xMc[0..12]
*/
APCM_quantization_xmaxc_to_exp_mant( xmaxc, &exp, &mant );
/* This computation uses the fact that the decoded version of xmaxc
* can be calculated by using the exponent and the mantissa part of
* xmaxc (logarithmic table).
* So, this method avoids any division and uses only a scaling
* of the RPE samples by a function of the exponent. A direct
* multiplication by the inverse of the mantissa (NRFAC[0..7]
* found in table 4.5) gives the 3 bit coded version xMc[0..12]
* of the RPE samples.
*/
/* Direct computation of xMc[0..12] using table 4.5
*/
assert( exp <= 4096 && exp >= -4096);
assert( mant >= 0 && mant <= 7 );
temp1 = 6 - exp; /* normalization by the exponent */
temp2 = gsm_NRFAC[ mant ]; /* inverse mantissa */
for (i = 0; i <= 12; i++) {
assert(temp1 >= 0 && temp1 < 16);
temp = xM[i] << temp1;
temp = GSM_MULT( temp, temp2 );
temp = SASR(temp, 12);
xMc[i] = temp + 4; /* see note below */
}
/* NOTE: This equation is used to make all the xMc[i] positive.
*/
*mant_out = mant;
*exp_out = exp;
*xmaxc_out = xmaxc;
}
static void Weighting_filter (
register word * e, /* signal [-5..0.39.44] IN */
word * x /* signal [0..39] OUT */
)
/*
* The coefficients of the weighting filter are stored in a table
* (see table 4.4). The following scaling is used:
*
* H[0..10] = integer( real_H[ 0..10] * 8192 );
*/
{
/* word wt[ 50 ]; */
register longword L_result;
register int k /* , i */ ;
/* Initialization of a temporary working array wt[0...49]
*/
/* for (k = 0; k <= 4; k++) wt[k] = 0;
* for (k = 5; k <= 44; k++) wt[k] = *e++;
* for (k = 45; k <= 49; k++) wt[k] = 0;
*
* (e[-5..-1] and e[40..44] are allocated by the caller,
* are initially zero and are not written anywhere.)
*/
e -= 5;
/* Compute the signal x[0..39]
*/
for (k = 0; k <= 39; k++) {
L_result = 8192 >> 1;
/* for (i = 0; i <= 10; i++) {
* L_temp = GSM_L_MULT( wt[k+i], gsm_H[i] );
* L_result = GSM_L_ADD( L_result, L_temp );
* }
*/
#undef STEP
#define STEP( i, H ) (e[ k + i ] * (longword)H)
/* Every one of these multiplications is done twice --
* but I don't see an elegant way to optimize this.
* Do you?
*/
#ifdef STUPID_COMPILER
L_result += STEP( 0, -134 ) ;
L_result += STEP( 1, -374 ) ;
/* + STEP( 2, 0 ) */
L_result += STEP( 3, 2054 ) ;
L_result += STEP( 4, 5741 ) ;
L_result += STEP( 5, 8192 ) ;
L_result += STEP( 6, 5741 ) ;
L_result += STEP( 7, 2054 ) ;
/* + STEP( 8, 0 ) */
L_result += STEP( 9, -374 ) ;
L_result += STEP( 10, -134 ) ;
#else
L_result +=
STEP( 0, -134 )
+ STEP( 1, -374 )
/* + STEP( 2, 0 ) */
+ STEP( 3, 2054 )
+ STEP( 4, 5741 )
+ STEP( 5, 8192 )
+ STEP( 6, 5741 )
+ STEP( 7, 2054 )
/* + STEP( 8, 0 ) */
+ STEP( 9, -374 )
+ STEP(10, -134 )
;
#endif
/* L_result = GSM_L_ADD( L_result, L_result ); (* scaling(x2) *)
* L_result = GSM_L_ADD( L_result, L_result ); (* scaling(x4) *)
*
* x[k] = SASR( L_result, 16 );
*/
/* 2 adds vs. >>16 => 14, minus one shift to compensate for
* those we lost when replacing L_MULT by '*'.
*/
L_result = SASR( L_result, 13 );
x[k] = ( L_result < MIN_WORD ? MIN_WORD
: (L_result > MAX_WORD ? MAX_WORD : L_result ));
}
}
void Gsm_Preprocess (
struct gsm_state * S,
word * s,
word * so ) /* [0..159] IN/OUT */
{
word z1 = S->z1;
longword L_z2 = S->L_z2;
word mp = S->mp;
word s1;
longword L_s2;
longword L_temp;
word msp, lsp;
word SO;
longword ltmp; /* for ADD */
ulongword utmp; /* for L_ADD */
register int k = 160;
while (k--) {
/* 4.2.1 Downscaling of the input signal
*/
SO = SASR( *s, 3 ) << 2;
s++;
assert (SO >= -0x4000); /* downscaled by */
assert (SO <= 0x3FFC); /* previous routine. */
/* 4.2.2 Offset compensation
*
* This part implements a high-pass filter and requires extended
* arithmetic precision for the recursive part of this filter.
* The input of this procedure is the array so[0...159] and the
* output the array sof[ 0...159 ].
*/
/* Compute the non-recursive part
*/
s1 = SO - z1; /* s1 = gsm_sub( *so, z1 ); */
z1 = SO;
assert(s1 != MIN_WORD);
/* Compute the recursive part
*/
L_s2 = s1;
L_s2 <<= 15;
/* Execution of a 31 bv 16 bits multiplication
*/
msp = SASR( L_z2, 15 );
lsp = L_z2-((longword)msp<<15); /* gsm_L_sub(L_z2,(msp<<15)); */
L_s2 += GSM_MULT_R( lsp, 32735 );
L_temp = (longword)msp * 32735; /* GSM_L_MULT(msp,32735) >> 1;*/
L_z2 = GSM_L_ADD( L_temp, L_s2 );
/* Compute sof[k] with rounding
*/
L_temp = GSM_L_ADD( L_z2, 16384 );
/* 4.2.3 Preemphasis
*/
msp = GSM_MULT_R( mp, -28180 );
mp = SASR( L_temp, 15 );
*so++ = GSM_ADD( mp, msp );
}
S->z1 = z1;
S->L_z2 = L_z2;
S->mp = mp;
}