/* ***** BEGIN LICENSE BLOCK ***** * Source last modified: $Id: sbrhfgen.c,v 1.2 2005/05/19 20:45:20 jrecker Exp $ * * Portions Copyright (c) 1995-2005 RealNetworks, Inc. All Rights Reserved. * * The contents of this file, and the files included with this file, * are subject to the current version of the RealNetworks Public * Source License (the "RPSL") available at * http://www.helixcommunity.org/content/rpsl unless you have licensed * the file under the current version of the RealNetworks Community * Source License (the "RCSL") available at * http://www.helixcommunity.org/content/rcsl, in which case the RCSL * will apply. You may also obtain the license terms directly from * RealNetworks. You may not use this file except in compliance with * the RPSL or, if you have a valid RCSL with RealNetworks applicable * to this file, the RCSL. Please see the applicable RPSL or RCSL for * the rights, obligations and limitations governing use of the * contents of the file. * * This file is part of the Helix DNA Technology. RealNetworks is the * developer of the Original Code and owns the copyrights in the * portions it created. * * This file, and the files included with this file, is distributed * and made available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY * KIND, EITHER EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS * ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET * ENJOYMENT OR NON-INFRINGEMENT. * * Technology Compatibility Kit Test Suite(s) Location: * http://www.helixcommunity.org/content/tck * * Contributor(s): * * ***** END LICENSE BLOCK ***** */ /************************************************************************************** * Fixed-point HE-AAC decoder * Jon Recker (jrecker@real.com) * February 2005 * * sbrhfgen.c - high frequency generation for SBR **************************************************************************************/ #include "sbr.h" #include "assembly.h" #define FBITS_LPCOEFS 29 /* Q29 for range of (-4, 4) */ #define MAG_16 (16 * (1 << (32 - (2*(32-FBITS_LPCOEFS))))) /* i.e. 16 in Q26 format */ #define RELAX_COEF 0x7ffff79c /* 1.0 / (1.0 + 1e-6), Q31 */ /* newBWTab[prev invfMode][curr invfMode], format = Q31 (table 4.158) * sample file which uses all of these: al_sbr_sr_64_2_fsaac32.aac */ static const int newBWTab[4][4] PROGMEM = { {0x00000000, 0x4ccccccd, 0x73333333, 0x7d70a3d7}, {0x4ccccccd, 0x60000000, 0x73333333, 0x7d70a3d7}, {0x00000000, 0x60000000, 0x73333333, 0x7d70a3d7}, {0x00000000, 0x60000000, 0x73333333, 0x7d70a3d7}, }; /************************************************************************************** * Function: CVKernel1 * * Description: kernel of covariance matrix calculation for p01, p11, p12, p22 * * Inputs: buffer of low-freq samples, starting at time index = 0, * freq index = patch subband * * Outputs: 64-bit accumulators for p01re, p01im, p12re, p12im, p11re, p22re * stored in accBuf * * Return: none * * Notes: this is carefully written to be efficient on ARM * use the assembly code version in sbrcov.s when building for ARM! **************************************************************************************/ #if (defined (XXXX__arm) && defined (__ARMCC_VERSION)) || (defined (_WIN32) && defined (_WIN32_WCE) && defined (ARM)) || (defined(__GNUC__) && defined(XXXX__arm__)) #ifdef __cplusplus extern "C" #endif void CVKernel1(int *XBuf, int *accBuf); #else void CVKernel1(int *XBuf, int *accBuf) { U64 p01re, p01im, p12re, p12im, p11re, p22re; int n, x0re, x0im, x1re, x1im; x0re = XBuf[0]; x0im = XBuf[1]; XBuf += (2*64); x1re = XBuf[0]; x1im = XBuf[1]; XBuf += (2*64); p01re.w64 = p01im.w64 = 0; p12re.w64 = p12im.w64 = 0; p11re.w64 = 0; p22re.w64 = 0; p12re.w64 = MADD64(p12re.w64, x1re, x0re); p12re.w64 = MADD64(p12re.w64, x1im, x0im); p12im.w64 = MADD64(p12im.w64, x0re, x1im); p12im.w64 = MADD64(p12im.w64, -x0im, x1re); p22re.w64 = MADD64(p22re.w64, x0re, x0re); p22re.w64 = MADD64(p22re.w64, x0im, x0im); for (n = (NUM_TIME_SLOTS*SAMPLES_PER_SLOT + 6); n != 0; n--) { /* 4 input, 3*2 acc, 1 ptr, 1 loop counter = 12 registers (use same for x0im, -x0im) */ x0re = x1re; x0im = x1im; x1re = XBuf[0]; x1im = XBuf[1]; p01re.w64 = MADD64(p01re.w64, x1re, x0re); p01re.w64 = MADD64(p01re.w64, x1im, x0im); p01im.w64 = MADD64(p01im.w64, x0re, x1im); p01im.w64 = MADD64(p01im.w64, -x0im, x1re); p11re.w64 = MADD64(p11re.w64, x0re, x0re); p11re.w64 = MADD64(p11re.w64, x0im, x0im); XBuf += (2*64); } /* these can be derived by slight changes to account for boundary conditions */ p12re.w64 += p01re.w64; p12re.w64 = MADD64(p12re.w64, x1re, -x0re); p12re.w64 = MADD64(p12re.w64, x1im, -x0im); p12im.w64 += p01im.w64; p12im.w64 = MADD64(p12im.w64, x0re, -x1im); p12im.w64 = MADD64(p12im.w64, x0im, x1re); p22re.w64 += p11re.w64; p22re.w64 = MADD64(p22re.w64, x0re, -x0re); p22re.w64 = MADD64(p22re.w64, x0im, -x0im); accBuf[0] = p01re.r.lo32; accBuf[1] = p01re.r.hi32; accBuf[2] = p01im.r.lo32; accBuf[3] = p01im.r.hi32; accBuf[4] = p11re.r.lo32; accBuf[5] = p11re.r.hi32; accBuf[6] = p12re.r.lo32; accBuf[7] = p12re.r.hi32; accBuf[8] = p12im.r.lo32; accBuf[9] = p12im.r.hi32; accBuf[10] = p22re.r.lo32; accBuf[11] = p22re.r.hi32; } #endif /************************************************************************************** * Function: CalcCovariance1 * * Description: calculate covariance matrix for p01, p12, p11, p22 (4.6.18.6.2) * * Inputs: buffer of low-freq samples, starting at time index 0, * freq index = patch subband * * Outputs: complex covariance elements p01re, p01im, p12re, p12im, p11re, p22re * (p11im = p22im = 0) * format = integer (Q0) * 2^N, with scalefactor N >= 0 * * Return: scalefactor N * * Notes: outputs are normalized to have 1 GB (sign in at least top 2 bits) **************************************************************************************/ static int CalcCovariance1(int *XBuf, int *p01reN, int *p01imN, int *p12reN, int *p12imN, int *p11reN, int *p22reN) { int accBuf[2*6]; int n, z, s, loShift, hiShift, gbMask; U64 p01re, p01im, p12re, p12im, p11re, p22re; CVKernel1(XBuf, accBuf); p01re.r.lo32 = accBuf[0]; p01re.r.hi32 = accBuf[1]; p01im.r.lo32 = accBuf[2]; p01im.r.hi32 = accBuf[3]; p11re.r.lo32 = accBuf[4]; p11re.r.hi32 = accBuf[5]; p12re.r.lo32 = accBuf[6]; p12re.r.hi32 = accBuf[7]; p12im.r.lo32 = accBuf[8]; p12im.r.hi32 = accBuf[9]; p22re.r.lo32 = accBuf[10]; p22re.r.hi32 = accBuf[11]; /* 64-bit accumulators now have 2*FBITS_OUT_QMFA fraction bits * want to scale them down to integers (32-bit signed, Q0) * with scale factor of 2^n, n >= 0 * leave 2 GB's for calculating determinant, so take top 30 non-zero bits */ gbMask = ((p01re.r.hi32) ^ (p01re.r.hi32 >> 31)) | ((p01im.r.hi32) ^ (p01im.r.hi32 >> 31)); gbMask |= ((p12re.r.hi32) ^ (p12re.r.hi32 >> 31)) | ((p12im.r.hi32) ^ (p12im.r.hi32 >> 31)); gbMask |= ((p11re.r.hi32) ^ (p11re.r.hi32 >> 31)) | ((p22re.r.hi32) ^ (p22re.r.hi32 >> 31)); if (gbMask == 0) { s = p01re.r.hi32 >> 31; gbMask = (p01re.r.lo32 ^ s) - s; s = p01im.r.hi32 >> 31; gbMask |= (p01im.r.lo32 ^ s) - s; s = p12re.r.hi32 >> 31; gbMask |= (p12re.r.lo32 ^ s) - s; s = p12im.r.hi32 >> 31; gbMask |= (p12im.r.lo32 ^ s) - s; s = p11re.r.hi32 >> 31; gbMask |= (p11re.r.lo32 ^ s) - s; s = p22re.r.hi32 >> 31; gbMask |= (p22re.r.lo32 ^ s) - s; z = 32 + CLZ(gbMask); } else { gbMask = FASTABS(p01re.r.hi32) | FASTABS(p01im.r.hi32); gbMask |= FASTABS(p12re.r.hi32) | FASTABS(p12im.r.hi32); gbMask |= FASTABS(p11re.r.hi32) | FASTABS(p22re.r.hi32); z = CLZ(gbMask); } n = 64 - z; /* number of non-zero bits in bottom of 64-bit word */ if (n <= 30) { loShift = (30 - n); *p01reN = p01re.r.lo32 << loShift; *p01imN = p01im.r.lo32 << loShift; *p12reN = p12re.r.lo32 << loShift; *p12imN = p12im.r.lo32 << loShift; *p11reN = p11re.r.lo32 << loShift; *p22reN = p22re.r.lo32 << loShift; return -(loShift + 2*FBITS_OUT_QMFA); } else if (n < 32 + 30) { loShift = (n - 30); hiShift = 32 - loShift; *p01reN = (p01re.r.hi32 << hiShift) | (p01re.r.lo32 >> loShift); *p01imN = (p01im.r.hi32 << hiShift) | (p01im.r.lo32 >> loShift); *p12reN = (p12re.r.hi32 << hiShift) | (p12re.r.lo32 >> loShift); *p12imN = (p12im.r.hi32 << hiShift) | (p12im.r.lo32 >> loShift); *p11reN = (p11re.r.hi32 << hiShift) | (p11re.r.lo32 >> loShift); *p22reN = (p22re.r.hi32 << hiShift) | (p22re.r.lo32 >> loShift); return (loShift - 2*FBITS_OUT_QMFA); } else { hiShift = n - (32 + 30); *p01reN = p01re.r.hi32 >> hiShift; *p01imN = p01im.r.hi32 >> hiShift; *p12reN = p12re.r.hi32 >> hiShift; *p12imN = p12im.r.hi32 >> hiShift; *p11reN = p11re.r.hi32 >> hiShift; *p22reN = p22re.r.hi32 >> hiShift; return (32 - 2*FBITS_OUT_QMFA - hiShift); } return 0; } /************************************************************************************** * Function: CVKernel2 * * Description: kernel of covariance matrix calculation for p02 * * Inputs: buffer of low-freq samples, starting at time index = 0, * freq index = patch subband * * Outputs: 64-bit accumulators for p02re, p02im stored in accBuf * * Return: none * * Notes: this is carefully written to be efficient on ARM * use the assembly code version in sbrcov.s when building for ARM! **************************************************************************************/ #if (defined (XXXX__arm) && defined (__ARMCC_VERSION)) || (defined (_WIN32) && defined (_WIN32_WCE) && defined (ARM)) || (defined(__GNUC__) && defined(XXXX__arm__)) #ifdef __cplusplus extern "C" #endif void CVKernel2(int *XBuf, int *accBuf); #else void CVKernel2(int *XBuf, int *accBuf) { U64 p02re, p02im; int n, x0re, x0im, x1re, x1im, x2re, x2im; p02re.w64 = p02im.w64 = 0; x0re = XBuf[0]; x0im = XBuf[1]; XBuf += (2*64); x1re = XBuf[0]; x1im = XBuf[1]; XBuf += (2*64); for (n = (NUM_TIME_SLOTS*SAMPLES_PER_SLOT + 6); n != 0; n--) { /* 6 input, 2*2 acc, 1 ptr, 1 loop counter = 12 registers (use same for x0im, -x0im) */ x2re = XBuf[0]; x2im = XBuf[1]; p02re.w64 = MADD64(p02re.w64, x2re, x0re); p02re.w64 = MADD64(p02re.w64, x2im, x0im); p02im.w64 = MADD64(p02im.w64, x0re, x2im); p02im.w64 = MADD64(p02im.w64, -x0im, x2re); x0re = x1re; x0im = x1im; x1re = x2re; x1im = x2im; XBuf += (2*64); } accBuf[0] = p02re.r.lo32; accBuf[1] = p02re.r.hi32; accBuf[2] = p02im.r.lo32; accBuf[3] = p02im.r.hi32; } #endif /************************************************************************************** * Function: CalcCovariance2 * * Description: calculate covariance matrix for p02 (4.6.18.6.2) * * Inputs: buffer of low-freq samples, starting at time index = 0, * freq index = patch subband * * Outputs: complex covariance element p02re, p02im * format = integer (Q0) * 2^N, with scalefactor N >= 0 * * Return: scalefactor N * * Notes: outputs are normalized to have 1 GB (sign in at least top 2 bits) **************************************************************************************/ static int CalcCovariance2(int *XBuf, int *p02reN, int *p02imN) { U64 p02re, p02im; int n, z, s, loShift, hiShift, gbMask; int accBuf[2*2]; CVKernel2(XBuf, accBuf); p02re.r.lo32 = accBuf[0]; p02re.r.hi32 = accBuf[1]; p02im.r.lo32 = accBuf[2]; p02im.r.hi32 = accBuf[3]; /* 64-bit accumulators now have 2*FBITS_OUT_QMFA fraction bits * want to scale them down to integers (32-bit signed, Q0) * with scale factor of 2^n, n >= 0 * leave 1 GB for calculating determinant, so take top 30 non-zero bits */ gbMask = ((p02re.r.hi32) ^ (p02re.r.hi32 >> 31)) | ((p02im.r.hi32) ^ (p02im.r.hi32 >> 31)); if (gbMask == 0) { s = p02re.r.hi32 >> 31; gbMask = (p02re.r.lo32 ^ s) - s; s = p02im.r.hi32 >> 31; gbMask |= (p02im.r.lo32 ^ s) - s; z = 32 + CLZ(gbMask); } else { gbMask = FASTABS(p02re.r.hi32) | FASTABS(p02im.r.hi32); z = CLZ(gbMask); } n = 64 - z; /* number of non-zero bits in bottom of 64-bit word */ if (n <= 30) { loShift = (30 - n); *p02reN = p02re.r.lo32 << loShift; *p02imN = p02im.r.lo32 << loShift; return -(loShift + 2*FBITS_OUT_QMFA); } else if (n < 32 + 30) { loShift = (n - 30); hiShift = 32 - loShift; *p02reN = (p02re.r.hi32 << hiShift) | (p02re.r.lo32 >> loShift); *p02imN = (p02im.r.hi32 << hiShift) | (p02im.r.lo32 >> loShift); return (loShift - 2*FBITS_OUT_QMFA); } else { hiShift = n - (32 + 30); *p02reN = p02re.r.hi32 >> hiShift; *p02imN = p02im.r.hi32 >> hiShift; return (32 - 2*FBITS_OUT_QMFA - hiShift); } return 0; } /************************************************************************************** * Function: CalcLPCoefs * * Description: calculate linear prediction coefficients for one subband (4.6.18.6.2) * * Inputs: buffer of low-freq samples, starting at time index = 0, * freq index = patch subband * number of guard bits in input sample buffer * * Outputs: complex LP coefficients a0re, a0im, a1re, a1im, format = Q29 * * Return: none * * Notes: output coefficients (a0re, a0im, a1re, a1im) clipped to range (-4, 4) * if the comples coefficients have magnitude >= 4.0, they are all * set to 0 (see spec) **************************************************************************************/ static void CalcLPCoefs(int *XBuf, int *a0re, int *a0im, int *a1re, int *a1im, int gb) { int zFlag, n1, n2, nd, d, dInv, tre, tim; int p01re, p01im, p02re, p02im, p12re, p12im, p11re, p22re; /* pre-scale to avoid overflow - probably never happens in practice (see QMFA) * max bit growth per accumulator = 38*2 = 76 mul-adds (X * X) * using 64-bit MADD, so if X has n guard bits, X*X has 2n+1 guard bits * gain 1 extra sign bit per multiply, so ensure ceil(log2(76/2) / 2) = 3 guard bits on inputs */ if (gb < 3) { nd = 3 - gb; for (n1 = (NUM_TIME_SLOTS*SAMPLES_PER_SLOT + 6 + 2); n1 != 0; n1--) { XBuf[0] >>= nd; XBuf[1] >>= nd; XBuf += (2*64); } XBuf -= (2*64*(NUM_TIME_SLOTS*SAMPLES_PER_SLOT + 6 + 2)); } /* calculate covariance elements */ n1 = CalcCovariance1(XBuf, &p01re, &p01im, &p12re, &p12im, &p11re, &p22re); n2 = CalcCovariance2(XBuf, &p02re, &p02im); /* normalize everything to larger power of 2 scalefactor, call it n1 */ if (n1 < n2) { nd = MIN(n2 - n1, 31); p01re >>= nd; p01im >>= nd; p12re >>= nd; p12im >>= nd; p11re >>= nd; p22re >>= nd; n1 = n2; } else if (n1 > n2) { nd = MIN(n1 - n2, 31); p02re >>= nd; p02im >>= nd; } /* calculate determinant of covariance matrix (at least 1 GB in pXX) */ d = MULSHIFT32(p12re, p12re) + MULSHIFT32(p12im, p12im); d = MULSHIFT32(d, RELAX_COEF) << 1; d = MULSHIFT32(p11re, p22re) - d; ASSERT(d >= 0); /* should never be < 0 */ zFlag = 0; *a0re = *a0im = 0; *a1re = *a1im = 0; if (d > 0) { /* input = Q31 d = Q(-2*n1 - 32 + nd) = Q31 * 2^(31 + 2*n1 + 32 - nd) * inverse = Q29 dInv = Q29 * 2^(-31 - 2*n1 - 32 + nd) = Q(29 + 31 + 2*n1 + 32 - nd) * * numerator has same Q format as d, since it's sum of normalized squares * so num * inverse = Q(-2*n1 - 32) * Q(29 + 31 + 2*n1 + 32 - nd) * = Q(29 + 31 - nd), drop low 32 in MULSHIFT32 * = Q(29 + 31 - 32 - nd) = Q(28 - nd) */ nd = CLZ(d) - 1; d <<= nd; dInv = InvRNormalized(d); /* 1 GB in pXX */ tre = MULSHIFT32(p01re, p12re) - MULSHIFT32(p01im, p12im) - MULSHIFT32(p02re, p11re); tre = MULSHIFT32(tre, dInv); tim = MULSHIFT32(p01re, p12im) + MULSHIFT32(p01im, p12re) - MULSHIFT32(p02im, p11re); tim = MULSHIFT32(tim, dInv); /* if d is extremely small, just set coefs to 0 (would have poor precision anyway) */ if (nd > 28 || (FASTABS(tre) >> (28 - nd)) >= 4 || (FASTABS(tim) >> (28 - nd)) >= 4) { zFlag = 1; } else { *a1re = tre << (FBITS_LPCOEFS - 28 + nd); /* i.e. convert Q(28 - nd) to Q(29) */ *a1im = tim << (FBITS_LPCOEFS - 28 + nd); } } if (p11re) { /* input = Q31 p11re = Q(-n1 + nd) = Q31 * 2^(31 + n1 - nd) * inverse = Q29 dInv = Q29 * 2^(-31 - n1 + nd) = Q(29 + 31 + n1 - nd) * * numerator is Q(-n1 - 3) * so num * inverse = Q(-n1 - 3) * Q(29 + 31 + n1 - nd) * = Q(29 + 31 - 3 - nd), drop low 32 in MULSHIFT32 * = Q(29 + 31 - 3 - 32 - nd) = Q(25 - nd) */ nd = CLZ(p11re) - 1; /* assume positive */ p11re <<= nd; dInv = InvRNormalized(p11re); /* a1re, a1im = Q29, so scaled by (n1 + 3) */ tre = (p01re >> 3) + MULSHIFT32(p12re, *a1re) + MULSHIFT32(p12im, *a1im); tre = -MULSHIFT32(tre, dInv); tim = (p01im >> 3) - MULSHIFT32(p12im, *a1re) + MULSHIFT32(p12re, *a1im); tim = -MULSHIFT32(tim, dInv); if (nd > 25 || (FASTABS(tre) >> (25 - nd)) >= 4 || (FASTABS(tim) >> (25 - nd)) >= 4) { zFlag = 1; } else { *a0re = tre << (FBITS_LPCOEFS - 25 + nd); /* i.e. convert Q(25 - nd) to Q(29) */ *a0im = tim << (FBITS_LPCOEFS - 25 + nd); } } /* see 4.6.18.6.2 - if magnitude of a0 or a1 >= 4 then a0 = a1 = 0 * i.e. a0re < 4, a0im < 4, a1re < 4, a1im < 4 * Q29*Q29 = Q26 */ if (zFlag || MULSHIFT32(*a0re, *a0re) + MULSHIFT32(*a0im, *a0im) >= MAG_16 || MULSHIFT32(*a1re, *a1re) + MULSHIFT32(*a1im, *a1im) >= MAG_16) { *a0re = *a0im = 0; *a1re = *a1im = 0; } /* no need to clip - we never changed the XBuf data, just used it to calculate a0 and a1 */ if (gb < 3) { nd = 3 - gb; for (n1 = (NUM_TIME_SLOTS*SAMPLES_PER_SLOT + 6 + 2); n1 != 0; n1--) { XBuf[0] <<= nd; XBuf[1] <<= nd; XBuf += (2*64); } } } /************************************************************************************** * Function: GenerateHighFreq * * Description: generate high frequencies with SBR (4.6.18.6) * * Inputs: initialized PSInfoSBR struct * initialized SBRGrid struct for this channel * initialized SBRFreq struct for this SCE/CPE block * initialized SBRChan struct for this channel * index of current channel (0 for SCE, 0 or 1 for CPE) * * Outputs: new high frequency samples starting at frequency kStart * * Return: none **************************************************************************************/ void GenerateHighFreq(PSInfoSBR *psi, SBRGrid *sbrGrid, SBRFreq *sbrFreq, SBRChan *sbrChan, int ch) { int band, newBW, c, t, gb, gbMask, gbIdx; int currPatch, p, x, k, g, i, iStart, iEnd, bw, bwsq; int a0re, a0im, a1re, a1im; int x1re, x1im, x2re, x2im; int ACCre, ACCim; int *XBufLo, *XBufHi; (void) ch; /* calculate array of chirp factors */ for (band = 0; band < sbrFreq->numNoiseFloorBands; band++) { c = sbrChan->chirpFact[band]; /* previous (bwArray') */ newBW = newBWTab[sbrChan->invfMode[0][band]][sbrChan->invfMode[1][band]]; /* weighted average of new and old (can't overflow - total gain = 1.0) */ if (newBW < c) t = MULSHIFT32(newBW, 0x60000000) + MULSHIFT32(0x20000000, c); /* new is smaller: 0.75*new + 0.25*old */ else t = MULSHIFT32(newBW, 0x74000000) + MULSHIFT32(0x0c000000, c); /* new is larger: 0.90625*new + 0.09375*old */ t <<= 1; if (t < 0x02000000) /* below 0.015625, clip to 0 */ t = 0; if (t > 0x7f800000) /* clip to 0.99609375 */ t = 0x7f800000; /* save curr as prev for next time */ sbrChan->chirpFact[band] = t; sbrChan->invfMode[0][band] = sbrChan->invfMode[1][band]; } iStart = sbrGrid->envTimeBorder[0] + HF_ADJ; iEnd = sbrGrid->envTimeBorder[sbrGrid->numEnv] + HF_ADJ; /* generate new high freqs from low freqs, patches, and chirp factors */ k = sbrFreq->kStart; g = 0; bw = sbrChan->chirpFact[g]; bwsq = MULSHIFT32(bw, bw) << 1; gbMask = (sbrChan->gbMask[0] | sbrChan->gbMask[1]); /* older 32 | newer 8 */ gb = CLZ(gbMask) - 1; for (currPatch = 0; currPatch < sbrFreq->numPatches; currPatch++) { for (x = 0; x < sbrFreq->patchNumSubbands[currPatch]; x++) { /* map k to corresponding noise floor band */ if (k >= sbrFreq->freqNoise[g+1]) { g++; bw = sbrChan->chirpFact[g]; /* Q31 */ bwsq = MULSHIFT32(bw, bw) << 1; /* Q31 */ } p = sbrFreq->patchStartSubband[currPatch] + x; /* low QMF band */ XBufHi = psi->XBuf[iStart][k]; if (bw) { CalcLPCoefs(psi->XBuf[0][p], &a0re, &a0im, &a1re, &a1im, gb); a0re = MULSHIFT32(bw, a0re); /* Q31 * Q29 = Q28 */ a0im = MULSHIFT32(bw, a0im); a1re = MULSHIFT32(bwsq, a1re); a1im = MULSHIFT32(bwsq, a1im); XBufLo = psi->XBuf[iStart-2][p]; x2re = XBufLo[0]; /* RE{XBuf[n-2]} */ x2im = XBufLo[1]; /* IM{XBuf[n-2]} */ XBufLo += (64*2); x1re = XBufLo[0]; /* RE{XBuf[n-1]} */ x1im = XBufLo[1]; /* IM{XBuf[n-1]} */ XBufLo += (64*2); for (i = iStart; i < iEnd; i++) { /* a0re/im, a1re/im are Q28 with at least 1 GB, * so the summing for AACre/im is fine (1 GB in, plus 1 from MULSHIFT32) */ ACCre = MULSHIFT32(x2re, a1re) - MULSHIFT32(x2im, a1im); ACCim = MULSHIFT32(x2re, a1im) + MULSHIFT32(x2im, a1re); x2re = x1re; x2im = x1im; ACCre += MULSHIFT32(x1re, a0re) - MULSHIFT32(x1im, a0im); ACCim += MULSHIFT32(x1re, a0im) + MULSHIFT32(x1im, a0re); x1re = XBufLo[0]; /* RE{XBuf[n]} */ x1im = XBufLo[1]; /* IM{XBuf[n]} */ XBufLo += (64*2); /* lost 4 fbits when scaling by a0re/im, a1re/im (Q28) */ CLIP_2N_SHIFT30(ACCre, 4); ACCre += x1re; CLIP_2N_SHIFT30(ACCim, 4); ACCim += x1im; XBufHi[0] = ACCre; XBufHi[1] = ACCim; XBufHi += (64*2); /* update guard bit masks */ gbMask = FASTABS(ACCre); gbMask |= FASTABS(ACCim); gbIdx = (i >> 5) & 0x01; /* 0 if i < 32, 1 if i >= 32 */ sbrChan->gbMask[gbIdx] |= gbMask; } } else { XBufLo = (int *)psi->XBuf[iStart][p]; for (i = iStart; i < iEnd; i++) { XBufHi[0] = XBufLo[0]; XBufHi[1] = XBufLo[1]; XBufLo += (64*2); XBufHi += (64*2); } } k++; /* high QMF band */ } } }