/src/opus/silk/fixed/burg_modified_FIX.c

Source (jump to first uncovered line)
/***********************************************************************
Copyright (c) 2006-2011, Skype Limited. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
- Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
- Neither the name of Internet Society, IETF or IETF Trust, nor the
names of specific contributors, may be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
***********************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "SigProc_FIX.h"
#include "define.h"
#include "tuning_parameters.h"
#include "pitch.h"

#define MAX_FRAME_SIZE              384             /* subfr_length * nb_subfr = ( 0.005 * 16000 + 16 ) * 4 = 384 */

#define QA                          25
#define N_BITS_HEAD_ROOM            3
#define MIN_RSHIFTS                 -16
#define MAX_RSHIFTS                 (32 - QA)

/* Compute reflection coefficients from input signal */
void silk_burg_modified_c(
    opus_int32                  *res_nrg,           /* O    Residual energy                                             */
    opus_int                    *res_nrg_Q,         /* O    Residual energy Q value                                     */
    opus_int32                  A_Q16[],            /* O    Prediction coefficients (length order)                      */
    const opus_int16            x[],                /* I    Input signal, length: nb_subfr * ( D + subfr_length )       */
    const opus_int32            minInvGain_Q30,     /* I    Inverse of max prediction gain                              */
    const opus_int              subfr_length,       /* I    Input signal subframe length (incl. D preceding samples)    */
    const opus_int              nb_subfr,           /* I    Number of subframes stacked in x                            */
    const opus_int              D,                  /* I    Order                                                       */
    int                         arch                /* I    Run-time architecture                                       */
)
{
    opus_int         k, n, s, lz, rshifts, reached_max_gain;
    opus_int32       C0, num, nrg, rc_Q31, invGain_Q30, Atmp_QA, Atmp1, tmp1, tmp2, x1, x2;
    const opus_int16 *x_ptr;
    opus_int32       C_first_row[ SILK_MAX_ORDER_LPC ];
    opus_int32       C_last_row[  SILK_MAX_ORDER_LPC ];
    opus_int32       Af_QA[       SILK_MAX_ORDER_LPC ];
    opus_int32       CAf[ SILK_MAX_ORDER_LPC + 1 ];
    opus_int32       CAb[ SILK_MAX_ORDER_LPC + 1 ];
    opus_int32       xcorr[ SILK_MAX_ORDER_LPC ];
    opus_int64       C0_64;

    celt_assert( subfr_length * nb_subfr <= MAX_FRAME_SIZE );

    /* Compute autocorrelations, added over subframes */
    C0_64 = silk_inner_prod16( x, x, subfr_length*nb_subfr, arch );
    lz = silk_CLZ64(C0_64);
    rshifts = 32 + 1 + N_BITS_HEAD_ROOM - lz;
    if (rshifts > MAX_RSHIFTS) rshifts = MAX_RSHIFTS;
    if (rshifts < MIN_RSHIFTS) rshifts = MIN_RSHIFTS;

    if (rshifts > 0) {
        C0 = (opus_int32)silk_RSHIFT64(C0_64, rshifts );
    } else {
        C0 = silk_LSHIFT32((opus_int32)C0_64, -rshifts );
    }

    CAb[ 0 ] = CAf[ 0 ] = C0 + silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ) + 1;                                /* Q(-rshifts) */
    silk_memset( C_first_row, 0, SILK_MAX_ORDER_LPC * sizeof( opus_int32 ) );
    if( rshifts > 0 ) {
        for( s = 0; s < nb_subfr; s++ ) {
            x_ptr = x + s * subfr_length;
            for( n = 1; n < D + 1; n++ ) {
                C_first_row[ n - 1 ] += (opus_int32)silk_RSHIFT64(
                    silk_inner_prod16( x_ptr, x_ptr + n, subfr_length - n, arch ), rshifts );
            }
        }
    } else {
        for( s = 0; s < nb_subfr; s++ ) {
            int i;
            opus_int32 d;
            x_ptr = x + s * subfr_length;
            celt_pitch_xcorr(x_ptr, x_ptr + 1, xcorr, subfr_length - D, D, arch );
            for( n = 1; n < D + 1; n++ ) {
               for ( i = n + subfr_length - D, d = 0; i < subfr_length; i++ )
                  d = MAC16_16( d, x_ptr[ i ], x_ptr[ i - n ] );
               xcorr[ n - 1 ] += d;
            }
            for( n = 1; n < D + 1; n++ ) {
                C_first_row[ n - 1 ] += silk_LSHIFT32( xcorr[ n - 1 ], -rshifts );
            }
        }
    }
    silk_memcpy( C_last_row, C_first_row, SILK_MAX_ORDER_LPC * sizeof( opus_int32 ) );

    /* Initialize */
    CAb[ 0 ] = CAf[ 0 ] = C0 + silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ) + 1;                                /* Q(-rshifts) */

    invGain_Q30 = (opus_int32)1 << 30;
    reached_max_gain = 0;
    for( n = 0; n < D; n++ ) {
        /* Update first row of correlation matrix (without first element) */
        /* Update last row of correlation matrix (without last element, stored in reversed order) */
        /* Update C * Af */
        /* Update C * flipud(Af) (stored in reversed order) */
        if( rshifts > -2 ) {
            for( s = 0; s < nb_subfr; s++ ) {
                x_ptr = x + s * subfr_length;
                x1  = -silk_LSHIFT32( (opus_int32)x_ptr[ n ],                    16 - rshifts );        /* Q(16-rshifts) */
                x2  = -silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], 16 - rshifts );        /* Q(16-rshifts) */
                tmp1 = silk_LSHIFT32( (opus_int32)x_ptr[ n ],                    QA - 16 );             /* Q(QA-16) */
                tmp2 = silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], QA - 16 );             /* Q(QA-16) */
                for( k = 0; k < n; k++ ) {
                    C_first_row[ k ] = silk_SMLAWB( C_first_row[ k ], x1, x_ptr[ n - k - 1 ]            ); /* Q( -rshifts ) */
                    C_last_row[ k ]  = silk_SMLAWB( C_last_row[ k ],  x2, x_ptr[ subfr_length - n + k ] ); /* Q( -rshifts ) */
                    Atmp_QA = Af_QA[ k ];
                    tmp1 = silk_SMLAWB( tmp1, Atmp_QA, x_ptr[ n - k - 1 ]            );                 /* Q(QA-16) */
                    tmp2 = silk_SMLAWB( tmp2, Atmp_QA, x_ptr[ subfr_length - n + k ] );                 /* Q(QA-16) */
                }
                tmp1 = silk_LSHIFT32( -tmp1, 32 - QA - rshifts );                                       /* Q(16-rshifts) */
                tmp2 = silk_LSHIFT32( -tmp2, 32 - QA - rshifts );                                       /* Q(16-rshifts) */
                for( k = 0; k <= n; k++ ) {
                    CAf[ k ] = silk_SMLAWB( CAf[ k ], tmp1, x_ptr[ n - k ]                    );        /* Q( -rshift ) */
                    CAb[ k ] = silk_SMLAWB( CAb[ k ], tmp2, x_ptr[ subfr_length - n + k - 1 ] );        /* Q( -rshift ) */
                }
            }
        } else {
            for( s = 0; s < nb_subfr; s++ ) {
                x_ptr = x + s * subfr_length;
                x1  = -silk_LSHIFT32( (opus_int32)x_ptr[ n ],                    -rshifts );            /* Q( -rshifts ) */
                x2  = -silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], -rshifts );            /* Q( -rshifts ) */
                tmp1 = silk_LSHIFT32( (opus_int32)x_ptr[ n ],                    17 );                  /* Q17 */
                tmp2 = silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], 17 );                  /* Q17 */
                for( k = 0; k < n; k++ ) {
                    C_first_row[ k ] = silk_MLA( C_first_row[ k ], x1, x_ptr[ n - k - 1 ]            ); /* Q( -rshifts ) */
                    C_last_row[ k ]  = silk_MLA( C_last_row[ k ],  x2, x_ptr[ subfr_length - n + k ] ); /* Q( -rshifts ) */
                    Atmp1 = silk_RSHIFT_ROUND( Af_QA[ k ], QA - 17 );                                   /* Q17 */
                    /* We sometimes get overflows in the multiplications (even beyond +/- 2^32),
                       but they cancel each other and the real result seems to always fit in a 32-bit
                       signed integer. This was determined experimentally, not theoretically (unfortunately). */
                    tmp1 = silk_MLA_ovflw( tmp1, x_ptr[ n - k - 1 ],            Atmp1 );                      /* Q17 */
                    tmp2 = silk_MLA_ovflw( tmp2, x_ptr[ subfr_length - n + k ], Atmp1 );                      /* Q17 */
                }
                tmp1 = -tmp1;                                                                           /* Q17 */
                tmp2 = -tmp2;                                                                           /* Q17 */
                for( k = 0; k <= n; k++ ) {
                    CAf[ k ] = silk_SMLAWW( CAf[ k ], tmp1,
                        silk_LSHIFT32( (opus_int32)x_ptr[ n - k ], -rshifts - 1 ) );                    /* Q( -rshift ) */
                    CAb[ k ] = silk_SMLAWW( CAb[ k ], tmp2,
                        silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n + k - 1 ], -rshifts - 1 ) ); /* Q( -rshift ) */
                }
            }
        }

        /* Calculate nominator and denominator for the next order reflection (parcor) coefficient */
        tmp1 = C_first_row[ n ];                                                                        /* Q( -rshifts ) */
        tmp2 = C_last_row[ n ];                                                                         /* Q( -rshifts ) */
        num  = 0;                                                                                       /* Q( -rshifts ) */
        nrg  = silk_ADD32( CAb[ 0 ], CAf[ 0 ] );                                                        /* Q( 1-rshifts ) */
        for( k = 0; k < n; k++ ) {
            Atmp_QA = Af_QA[ k ];
            lz = silk_CLZ32( silk_abs( Atmp_QA ) ) - 1;
            lz = silk_min( 32 - QA, lz );
            Atmp1 = silk_LSHIFT32( Atmp_QA, lz );                                                       /* Q( QA + lz ) */

            tmp1 = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( C_last_row[  n - k - 1 ], Atmp1 ), 32 - QA - lz );  /* Q( -rshifts ) */
            tmp2 = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( C_first_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz );  /* Q( -rshifts ) */
            num  = silk_ADD_LSHIFT32( num,  silk_SMMUL( CAb[ n - k ],             Atmp1 ), 32 - QA - lz );  /* Q( -rshifts ) */
            nrg  = silk_ADD_LSHIFT32( nrg,  silk_SMMUL( silk_ADD32( CAb[ k + 1 ], CAf[ k + 1 ] ),
                                                                                Atmp1 ), 32 - QA - lz );    /* Q( 1-rshifts ) */
        }
        CAf[ n + 1 ] = tmp1;                                                                            /* Q( -rshifts ) */
        CAb[ n + 1 ] = tmp2;                                                                            /* Q( -rshifts ) */
        num = silk_ADD32( num, tmp2 );                                                                  /* Q( -rshifts ) */
        num = silk_LSHIFT32( -num, 1 );                                                                 /* Q( 1-rshifts ) */

        /* Calculate the next order reflection (parcor) coefficient */
        if( silk_abs( num ) < nrg ) {
            rc_Q31 = silk_DIV32_varQ( num, nrg, 31 );
        } else {
            rc_Q31 = ( num > 0 ) ? silk_int32_MAX : silk_int32_MIN;
        }

        /* Update inverse prediction gain */
        tmp1 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 );
        tmp1 = silk_LSHIFT( silk_SMMUL( invGain_Q30, tmp1 ), 2 );
        if( tmp1 <= minInvGain_Q30 ) {
            /* Max prediction gain exceeded; set reflection coefficient such that max prediction gain is exactly hit */
            tmp2 = ( (opus_int32)1 << 30 ) - silk_DIV32_varQ( minInvGain_Q30, invGain_Q30, 30 );            /* Q30 */
            rc_Q31 = silk_SQRT_APPROX( tmp2 );                                                  /* Q15 */
            if( rc_Q31 > 0 ) {
                /* Newton-Raphson iteration */
                rc_Q31 = silk_RSHIFT32( rc_Q31 + silk_DIV32( tmp2, rc_Q31 ), 1 );                       /* Q15 */
                rc_Q31 = silk_LSHIFT32( rc_Q31, 16 );                                                   /* Q31 */
                if( num < 0 ) {
                    /* Ensure adjusted reflection coefficients has the original sign */
                    rc_Q31 = -rc_Q31;
                }
            }
            invGain_Q30 = minInvGain_Q30;
            reached_max_gain = 1;
        } else {
            invGain_Q30 = tmp1;
        }

        /* Update the AR coefficients */
        for( k = 0; k < (n + 1) >> 1; k++ ) {
            tmp1 = Af_QA[ k ];                                                                  /* QA */
            tmp2 = Af_QA[ n - k - 1 ];                                                          /* QA */
            Af_QA[ k ]         = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( tmp2, rc_Q31 ), 1 );      /* QA */
            Af_QA[ n - k - 1 ] = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( tmp1, rc_Q31 ), 1 );      /* QA */
        }
        Af_QA[ n ] = silk_RSHIFT32( rc_Q31, 31 - QA );                                          /* QA */

        if( reached_max_gain ) {
            /* Reached max prediction gain; set remaining coefficients to zero and exit loop */
            for( k = n + 1; k < D; k++ ) {
                Af_QA[ k ] = 0;
            }
            break;
        }

        /* Update C * Af and C * Ab */
        for( k = 0; k <= n + 1; k++ ) {
            tmp1 = CAf[ k ];                                                                    /* Q( -rshifts ) */
            tmp2 = CAb[ n - k + 1 ];                                                            /* Q( -rshifts ) */
            CAf[ k ]         = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( tmp2, rc_Q31 ), 1 );        /* Q( -rshifts ) */
            CAb[ n - k + 1 ] = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( tmp1, rc_Q31 ), 1 );        /* Q( -rshifts ) */
        }
    }

    if( reached_max_gain ) {
        for( k = 0; k < D; k++ ) {
            /* Scale coefficients */
            A_Q16[ k ] = -silk_RSHIFT_ROUND( Af_QA[ k ], QA - 16 );
        }
        /* Subtract energy of preceding samples from C0 */
        if( rshifts > 0 ) {
            for( s = 0; s < nb_subfr; s++ ) {
                x_ptr = x + s * subfr_length;
                C0 -= (opus_int32)silk_RSHIFT64( silk_inner_prod16( x_ptr, x_ptr, D, arch ), rshifts );
            }
        } else {
            for( s = 0; s < nb_subfr; s++ ) {
                x_ptr = x + s * subfr_length;
                C0 -= silk_LSHIFT32( silk_inner_prod_aligned( x_ptr, x_ptr, D, arch), -rshifts);
            }
        }
        /* Approximate residual energy */
        *res_nrg = silk_LSHIFT( silk_SMMUL( invGain_Q30, C0 ), 2 );
        *res_nrg_Q = -rshifts;
    } else {
        /* Return residual energy */
        nrg  = CAf[ 0 ];                                                                            /* Q( -rshifts ) */
        tmp1 = (opus_int32)1 << 16;                                                                             /* Q16 */
        for( k = 0; k < D; k++ ) {
            Atmp1 = silk_RSHIFT_ROUND( Af_QA[ k ], QA - 16 );                                       /* Q16 */
            nrg  = silk_SMLAWW( nrg, CAf[ k + 1 ], Atmp1 );                                         /* Q( -rshifts ) */
            tmp1 = silk_SMLAWW( tmp1, Atmp1, Atmp1 );                                               /* Q16 */
            A_Q16[ k ] = -Atmp1;
        }
        *res_nrg = silk_SMLAWW( nrg, silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ), -tmp1 );/* Q( -rshifts ) */
        *res_nrg_Q = -rshifts;
    }
}

Coverage Report

Created: 2025-08-26 07:18

Line	Count	Source (jump to first uncovered line)
1		/***********************************************************************
2		Copyright (c) 2006-2011, Skype Limited. All rights reserved.
3		Redistribution and use in source and binary forms, with or without
4		modification, are permitted provided that the following conditions
5		are met:
6		- Redistributions of source code must retain the above copyright notice,
7		this list of conditions and the following disclaimer.
8		- Redistributions in binary form must reproduce the above copyright
9		notice, this list of conditions and the following disclaimer in the
10		documentation and/or other materials provided with the distribution.
11		- Neither the name of Internet Society, IETF or IETF Trust, nor the
12		names of specific contributors, may be used to endorse or promote
13		products derived from this software without specific prior written
14		permission.
15		THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16		AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17		IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18		ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
19		LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20		CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21		SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22		INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23		CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
24		ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25		POSSIBILITY OF SUCH DAMAGE.
26		***********************************************************************/
27
28		#ifdef HAVE_CONFIG_H
29		#include "config.h"
30		#endif
31
32		#include "SigProc_FIX.h"
33		#include "define.h"
34		#include "tuning_parameters.h"
35		#include "pitch.h"
36
37		#define MAX_FRAME_SIZE 384 /* subfr_length * nb_subfr = ( 0.005 * 16000 + 16 ) * 4 = 384 */
38
39	318k	#define QA 25
40	318k	#define N_BITS_HEAD_ROOM 3
41	419k	#define MIN_RSHIFTS -16
42	318k	#define MAX_RSHIFTS (32 - QA)
43
44		/* Compute reflection coefficients from input signal */
45		void silk_burg_modified_c(
46		opus_int32 res_nrg, / O Residual energy */
47		opus_int res_nrg_Q, / O Residual energy Q value */
48		opus_int32 A_Q16[], /* O Prediction coefficients (length order) */
49		const opus_int16 x[], /* I Input signal, length: nb_subfr * ( D + subfr_length ) */
50		const opus_int32 minInvGain_Q30, /* I Inverse of max prediction gain */
51		const opus_int subfr_length, /* I Input signal subframe length (incl. D preceding samples) */
52		const opus_int nb_subfr, /* I Number of subframes stacked in x */
53		const opus_int D, /* I Order */
54		int arch /* I Run-time architecture */
55		)
56	318k	{
57	318k	opus_int k, n, s, lz, rshifts, reached_max_gain;
58	318k	opus_int32 C0, num, nrg, rc_Q31, invGain_Q30, Atmp_QA, Atmp1, tmp1, tmp2, x1, x2;
59	318k	const opus_int16 *x_ptr;
60	318k	opus_int32 C_first_row[ SILK_MAX_ORDER_LPC ];
61	318k	opus_int32 C_last_row[ SILK_MAX_ORDER_LPC ];
62	318k	opus_int32 Af_QA[ SILK_MAX_ORDER_LPC ];
63	318k	opus_int32 CAf[ SILK_MAX_ORDER_LPC + 1 ];
64	318k	opus_int32 CAb[ SILK_MAX_ORDER_LPC + 1 ];
65	318k	opus_int32 xcorr[ SILK_MAX_ORDER_LPC ];
66	318k	opus_int64 C0_64;
67
68	318k	celt_assert( subfr_length * nb_subfr <= MAX_FRAME_SIZE );
69
70		/* Compute autocorrelations, added over subframes */
71	318k	C0_64 = silk_inner_prod16( x, x, subfr_length*nb_subfr, arch );
72	318k	lz = silk_CLZ64(C0_64);
73	318k	rshifts = 32 + 1 + N_BITS_HEAD_ROOM - lz;
74	318k	if (rshifts > MAX_RSHIFTS) rshifts = MAX_RSHIFTS;
75	318k	if (rshifts < MIN_RSHIFTS) rshifts = MIN_RSHIFTS;
76
77	318k	if (rshifts > 0) {
78	14.1k	C0 = (opus_int32)silk_RSHIFT64(C0_64, rshifts );
79	304k	} else {
80	304k	C0 = silk_LSHIFT32((opus_int32)C0_64, -rshifts );
81	304k	}
82
83	318k	CAb[ 0 ] = CAf[ 0 ] = C0 + silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ) + 1; /* Q(-rshifts) */
84	318k	silk_memset( C_first_row, 0, SILK_MAX_ORDER_LPC * sizeof( opus_int32 ) );
85	318k	if( rshifts > 0 ) {
86	63.6k	for( s = 0; s < nb_subfr; s++ ) {
87	49.5k	x_ptr = x + s * subfr_length;
88	615k	for( n = 1; n < D + 1; n++ ) {
89	566k	C_first_row[ n - 1 ] += (opus_int32)silk_RSHIFT64(
90	566k	silk_inner_prod16( x_ptr, x_ptr + n, subfr_length - n, arch ), rshifts );
91	566k	}
92	49.5k	}
93	304k	} else {
94	1.24M	for( s = 0; s < nb_subfr; s++ ) {
95	945k	int i;
96	945k	opus_int32 d;
97	945k	x_ptr = x + s * subfr_length;
98	945k	celt_pitch_xcorr(x_ptr, x_ptr + 1, xcorr, subfr_length - D, D, arch );
99	11.4M	for( n = 1; n < D + 1; n++ ) {
100	66.5M	for ( i = n + subfr_length - D, d = 0; i < subfr_length; i++ )
101	56.0M	d = MAC16_16( d, x_ptr[ i ], x_ptr[ i - n ] );
102	10.5M	xcorr[ n - 1 ] += d;
103	10.5M	}
104	11.4M	for( n = 1; n < D + 1; n++ ) {
105	10.5M	C_first_row[ n - 1 ] += silk_LSHIFT32( xcorr[ n - 1 ], -rshifts );
106	10.5M	}
107	945k	}
108	304k	}
109	318k	silk_memcpy( C_last_row, C_first_row, SILK_MAX_ORDER_LPC * sizeof( opus_int32 ) );
110
111		/* Initialize */
112	318k	CAb[ 0 ] = CAf[ 0 ] = C0 + silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ) + 1; /* Q(-rshifts) */
113
114	318k	invGain_Q30 = (opus_int32)1 << 30;
115	318k	reached_max_gain = 0;
116	3.71M	for( n = 0; n < D; n++ ) {
117		/* Update first row of correlation matrix (without first element) */
118		/* Update last row of correlation matrix (without last element, stored in reversed order) */
119		/* Update C * Af */
120		/* Update C * flipud(Af) (stored in reversed order) */
121	3.41M	if( rshifts > -2 ) {
122	1.92M	for( s = 0; s < nb_subfr; s++ ) {
123	1.49M	x_ptr = x + s * subfr_length;
124	1.49M	x1 = -silk_LSHIFT32( (opus_int32)x_ptr[ n ], 16 - rshifts ); /* Q(16-rshifts) */
125	1.49M	x2 = -silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], 16 - rshifts ); /* Q(16-rshifts) */
126	1.49M	tmp1 = silk_LSHIFT32( (opus_int32)x_ptr[ n ], QA - 16 ); /* Q(QA-16) */
127	1.49M	tmp2 = silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], QA - 16 ); /* Q(QA-16) */
128	9.68M	for( k = 0; k < n; k++ ) {
129	8.19M	C_first_row[ k ] = silk_SMLAWB( C_first_row[ k ], x1, x_ptr[ n - k - 1 ] ); /* Q( -rshifts ) */
130	8.19M	C_last_row[ k ] = silk_SMLAWB( C_last_row[ k ], x2, x_ptr[ subfr_length - n + k ] ); /* Q( -rshifts ) */
131	8.19M	Atmp_QA = Af_QA[ k ];
132	8.19M	tmp1 = silk_SMLAWB( tmp1, Atmp_QA, x_ptr[ n - k - 1 ] ); /* Q(QA-16) */
133	8.19M	tmp2 = silk_SMLAWB( tmp2, Atmp_QA, x_ptr[ subfr_length - n + k ] ); /* Q(QA-16) */
134	8.19M	}
135	1.49M	tmp1 = silk_LSHIFT32( -tmp1, 32 - QA - rshifts ); /* Q(16-rshifts) */
136	1.49M	tmp2 = silk_LSHIFT32( -tmp2, 32 - QA - rshifts ); /* Q(16-rshifts) */
137	11.1M	for( k = 0; k <= n; k++ ) {
138	9.68M	CAf[ k ] = silk_SMLAWB( CAf[ k ], tmp1, x_ptr[ n - k ] ); /* Q( -rshift ) */
139	9.68M	CAb[ k ] = silk_SMLAWB( CAb[ k ], tmp2, x_ptr[ subfr_length - n + k - 1 ] ); /* Q( -rshift ) */
140	9.68M	}
141	1.49M	}
142	2.98M	} else {
143	12.1M	for( s = 0; s < nb_subfr; s++ ) {
144	9.20M	x_ptr = x + s * subfr_length;
145	9.20M	x1 = -silk_LSHIFT32( (opus_int32)x_ptr[ n ], -rshifts ); /* Q( -rshifts ) */
146	9.20M	x2 = -silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], -rshifts ); /* Q( -rshifts ) */
147	9.20M	tmp1 = silk_LSHIFT32( (opus_int32)x_ptr[ n ], 17 ); /* Q17 */
148	9.20M	tmp2 = silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n - 1 ], 17 ); /* Q17 */
149	57.5M	for( k = 0; k < n; k++ ) {
150	48.3M	C_first_row[ k ] = silk_MLA( C_first_row[ k ], x1, x_ptr[ n - k - 1 ] ); /* Q( -rshifts ) */
151	48.3M	C_last_row[ k ] = silk_MLA( C_last_row[ k ], x2, x_ptr[ subfr_length - n + k ] ); /* Q( -rshifts ) */
152	48.3M	Atmp1 = silk_RSHIFT_ROUND( Af_QA[ k ], QA - 17 ); /* Q17 */
153		/* We sometimes get overflows in the multiplications (even beyond +/- 2^32),
154		but they cancel each other and the real result seems to always fit in a 32-bit
155		signed integer. This was determined experimentally, not theoretically (unfortunately). */
156	48.3M	tmp1 = silk_MLA_ovflw( tmp1, x_ptr[ n - k - 1 ], Atmp1 ); /* Q17 */
157	48.3M	tmp2 = silk_MLA_ovflw( tmp2, x_ptr[ subfr_length - n + k ], Atmp1 ); /* Q17 */
158	48.3M	}
159	9.20M	tmp1 = -tmp1; /* Q17 */
160	9.20M	tmp2 = -tmp2; /* Q17 */
161	66.7M	for( k = 0; k <= n; k++ ) {
162	57.5M	CAf[ k ] = silk_SMLAWW( CAf[ k ], tmp1,
163	57.5M	silk_LSHIFT32( (opus_int32)x_ptr[ n - k ], -rshifts - 1 ) ); /* Q( -rshift ) */
164	57.5M	CAb[ k ] = silk_SMLAWW( CAb[ k ], tmp2,
165	57.5M	silk_LSHIFT32( (opus_int32)x_ptr[ subfr_length - n + k - 1 ], -rshifts - 1 ) ); /* Q( -rshift ) */
166	57.5M	}
167	9.20M	}
168	2.98M	}
169
170		/* Calculate nominator and denominator for the next order reflection (parcor) coefficient */
171	3.41M	tmp1 = C_first_row[ n ]; /* Q( -rshifts ) */
172	3.41M	tmp2 = C_last_row[ n ]; /* Q( -rshifts ) */
173	3.41M	num = 0; /* Q( -rshifts ) */
174	3.41M	nrg = silk_ADD32( CAb[ 0 ], CAf[ 0 ] ); /* Q( 1-rshifts ) */
175	21.4M	for( k = 0; k < n; k++ ) {
176	18.0M	Atmp_QA = Af_QA[ k ];
177	18.0M	lz = silk_CLZ32( silk_abs( Atmp_QA ) ) - 1;
178	18.0M	lz = silk_min( 32 - QA, lz );
179	18.0M	Atmp1 = silk_LSHIFT32( Atmp_QA, lz ); /* Q( QA + lz ) */
180
181	18.0M	tmp1 = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( C_last_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz ); /* Q( -rshifts ) */
182	18.0M	tmp2 = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( C_first_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz ); /* Q( -rshifts ) */
183	18.0M	num = silk_ADD_LSHIFT32( num, silk_SMMUL( CAb[ n - k ], Atmp1 ), 32 - QA - lz ); /* Q( -rshifts ) */
184	18.0M	nrg = silk_ADD_LSHIFT32( nrg, silk_SMMUL( silk_ADD32( CAb[ k + 1 ], CAf[ k + 1 ] ),
185	18.0M	Atmp1 ), 32 - QA - lz ); /* Q( 1-rshifts ) */
186	18.0M	}
187	3.41M	CAf[ n + 1 ] = tmp1; /* Q( -rshifts ) */
188	3.41M	CAb[ n + 1 ] = tmp2; /* Q( -rshifts ) */
189	3.41M	num = silk_ADD32( num, tmp2 ); /* Q( -rshifts ) */
190	3.41M	num = silk_LSHIFT32( -num, 1 ); /* Q( 1-rshifts ) */
191
192		/* Calculate the next order reflection (parcor) coefficient */
193	3.41M	if( silk_abs( num ) < nrg ) {
194	3.41M	rc_Q31 = silk_DIV32_varQ( num, nrg, 31 );
195	3.41M	} else {
196	1	rc_Q31 = ( num > 0 ) ? silk_int32_MAX : silk_int32_MIN;
197	1	}
198
199		/* Update inverse prediction gain */
200	3.41M	tmp1 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 );
201	3.41M	tmp1 = silk_LSHIFT( silk_SMMUL( invGain_Q30, tmp1 ), 2 );
202	3.41M	if( tmp1 <= minInvGain_Q30 ) {
203		/* Max prediction gain exceeded; set reflection coefficient such that max prediction gain is exactly hit */
204	16.6k	tmp2 = ( (opus_int32)1 << 30 ) - silk_DIV32_varQ( minInvGain_Q30, invGain_Q30, 30 ); /* Q30 */
205	16.6k	rc_Q31 = silk_SQRT_APPROX( tmp2 ); /* Q15 */
206	16.6k	if( rc_Q31 > 0 ) {
207		/* Newton-Raphson iteration */
208	16.6k	rc_Q31 = silk_RSHIFT32( rc_Q31 + silk_DIV32( tmp2, rc_Q31 ), 1 ); /* Q15 */
209	16.6k	rc_Q31 = silk_LSHIFT32( rc_Q31, 16 ); /* Q31 */
210	16.6k	if( num < 0 ) {
211		/* Ensure adjusted reflection coefficients has the original sign */
212	13.6k	rc_Q31 = -rc_Q31;
213	13.6k	}
214	16.6k	}
215	16.6k	invGain_Q30 = minInvGain_Q30;
216	16.6k	reached_max_gain = 1;
217	3.40M	} else {
218	3.40M	invGain_Q30 = tmp1;
219	3.40M	}
220
221		/* Update the AR coefficients */
222	13.2M	for( k = 0; k < (n + 1) >> 1; k++ ) {
223	9.88M	tmp1 = Af_QA[ k ]; /* QA */
224	9.88M	tmp2 = Af_QA[ n - k - 1 ]; /* QA */
225	9.88M	Af_QA[ k ] = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( tmp2, rc_Q31 ), 1 ); /* QA */
226	9.88M	Af_QA[ n - k - 1 ] = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( tmp1, rc_Q31 ), 1 ); /* QA */
227	9.88M	}
228	3.41M	Af_QA[ n ] = silk_RSHIFT32( rc_Q31, 31 - QA ); /* QA */
229
230	3.41M	if( reached_max_gain ) {
231		/* Reached max prediction gain; set remaining coefficients to zero and exit loop */
232	147k	for( k = n + 1; k < D; k++ ) {
233	130k	Af_QA[ k ] = 0;
234	130k	}
235	16.6k	break;
236	16.6k	}
237
238		/* Update C * Af and C * Ab */
239	28.2M	for( k = 0; k <= n + 1; k++ ) {
240	24.8M	tmp1 = CAf[ k ]; /* Q( -rshifts ) */
241	24.8M	tmp2 = CAb[ n - k + 1 ]; /* Q( -rshifts ) */
242	24.8M	CAf[ k ] = silk_ADD_LSHIFT32( tmp1, silk_SMMUL( tmp2, rc_Q31 ), 1 ); /* Q( -rshifts ) */
243	24.8M	CAb[ n - k + 1 ] = silk_ADD_LSHIFT32( tmp2, silk_SMMUL( tmp1, rc_Q31 ), 1 ); /* Q( -rshifts ) */
244	24.8M	}
245	3.40M	}
246
247	318k	if( reached_max_gain ) {
248	205k	for( k = 0; k < D; k++ ) {
249		/* Scale coefficients */
250	188k	A_Q16[ k ] = -silk_RSHIFT_ROUND( Af_QA[ k ], QA - 16 );
251	188k	}
252		/* Subtract energy of preceding samples from C0 */
253	16.6k	if( rshifts > 0 ) {
254	13.2k	for( s = 0; s < nb_subfr; s++ ) {
255	10.1k	x_ptr = x + s * subfr_length;
256	10.1k	C0 -= (opus_int32)silk_RSHIFT64( silk_inner_prod16( x_ptr, x_ptr, D, arch ), rshifts );
257	10.1k	}
258	13.5k	} else {
259	54.5k	for( s = 0; s < nb_subfr; s++ ) {
260	41.0k	x_ptr = x + s * subfr_length;
261	41.0k	C0 -= silk_LSHIFT32( silk_inner_prod_aligned( x_ptr, x_ptr, D, arch), -rshifts);
262	41.0k	}
263	13.5k	}
264		/* Approximate residual energy */
265	16.6k	*res_nrg = silk_LSHIFT( silk_SMMUL( invGain_Q30, C0 ), 2 );
266	16.6k	*res_nrg_Q = -rshifts;
267	301k	} else {
268		/* Return residual energy */
269	301k	nrg = CAf[ 0 ]; /* Q( -rshifts ) */
270	301k	tmp1 = (opus_int32)1 << 16; /* Q16 */
271	3.66M	for( k = 0; k < D; k++ ) {
272	3.35M	Atmp1 = silk_RSHIFT_ROUND( Af_QA[ k ], QA - 16 ); /* Q16 */
273	3.35M	nrg = silk_SMLAWW( nrg, CAf[ k + 1 ], Atmp1 ); /* Q( -rshifts ) */
274	3.35M	tmp1 = silk_SMLAWW( tmp1, Atmp1, Atmp1 ); /* Q16 */
275	3.35M	A_Q16[ k ] = -Atmp1;
276	3.35M	}
277	301k	res_nrg = silk_SMLAWW( nrg, silk_SMMUL( SILK_FIX_CONST( FIND_LPC_COND_FAC, 32 ), C0 ), -tmp1 );/ Q( -rshifts ) */
278	301k	*res_nrg_Q = -rshifts;
279	301k	}
280	318k	}