lpc_bfin.h

00001 /* Copyright (C) 2005 Analog Devices */
00002 /**
00003    @file lpc_bfin.h
00004    @author Jean-Marc Valin 
00005    @brief Functions for LPC (Linear Prediction Coefficients) analysis (Blackfin version)
00006 */
00007 /*
00008    Redistribution and use in source and binary forms, with or without
00009    modification, are permitted provided that the following conditions
00010    are met:
00011    
00012    - Redistributions of source code must retain the above copyright
00013    notice, this list of conditions and the following disclaimer.
00014    
00015    - Redistributions in binary form must reproduce the above copyright
00016    notice, this list of conditions and the following disclaimer in the
00017    documentation and/or other materials provided with the distribution.
00018    
00019    - Neither the name of the Xiph.org Foundation nor the names of its
00020    contributors may be used to endorse or promote products derived from
00021    this software without specific prior written permission.
00022    
00023    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00024    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00025    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00026    A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
00027    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00028    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
00029    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00030    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00031    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00032    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00033    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00034 */
00035 
00036 #define OVERRIDE_SPEEX_AUTOCORR
00037 void _spx_autocorr(
00038 const spx_word16_t *x,   /*  in: [0...n-1] samples x   */
00039 spx_word16_t       *ac,  /* out: [0...lag-1] ac values */
00040 int          lag, 
00041 int          n
00042                   )
00043 {
00044    spx_word32_t d;
00045    const spx_word16_t *xs;
00046    int i, j;
00047    spx_word32_t ac0=1;
00048    spx_word32_t ac32[11], *ac32top;
00049    int shift, ac_shift;
00050    ac32top = ac32+lag-1;
00051    int lag_1, N_lag;
00052    int nshift;
00053    lag_1 = lag-1;
00054    N_lag = n-lag_1;
00055    for (j=0;j<n;j++)
00056       ac0 = ADD32(ac0,SHR32(MULT16_16(x[j],x[j]),8));
00057    ac0 = ADD32(ac0,n);
00058    shift = 8;
00059    while (shift && ac0<0x40000000)
00060    {
00061       shift--;
00062       ac0 <<= 1;
00063    }
00064    ac_shift = 18;
00065    while (ac_shift && ac0<0x40000000)
00066    {
00067       ac_shift--;
00068       ac0 <<= 1;
00069    }
00070    
00071    xs = x+lag-1;
00072    nshift = -shift;
00073    __asm__ __volatile__ 
00074    (
00075          "P2 = %0;\n\t"
00076          "I0 = P2;\n\t" /* x in I0 */
00077          "B0 = P2;\n\t" /* x in B0 */
00078          "R0 = %3;\n\t" /* len in R0 */
00079          "P3 = %3;\n\t" /* len in R0 */
00080          "P4 = %4;\n\t" /* nb_pitch in R0 */
00081          "R1 = R0 << 1;\n\t" /* number of bytes in x */
00082          "L0 = R1;\n\t"
00083          "P0 = %1;\n\t"
00084          "P1 = %2;\n\t"
00085          "B1 = P1;\n\t"
00086          "R4 = %5;\n\t"
00087          "L1 = 0;\n\t" /*Disable looping on I1*/
00088 
00089          "r0 = [I0++];\n\t"
00090          "R2 = 0;R3=0;"
00091          "LOOP pitch%= LC0 = P4 >> 1;\n\t"
00092          "LOOP_BEGIN pitch%=;\n\t"
00093             "I1 = P0;\n\t"
00094             "A1 = A0 = 0;\n\t"
00095             "R1 = [I1++];\n\t"
00096             "LOOP inner_prod%= LC1 = P3 >> 1;\n\t"
00097             "LOOP_BEGIN inner_prod%=;\n\t"
00098                "A1 += R0.L*R1.H, A0 += R0.L*R1.L (IS) || R1.L = W[I1++];\n\t"
00099                "A1 += R0.H*R1.L, A0 += R0.H*R1.H (IS) || R1.H = W[I1++] || R0 = [I0++];\n\t"
00100             "LOOP_END inner_prod%=;\n\t"
00101             "A0 = ASHIFT A0 by R4.L;\n\t"
00102             "A1 = ASHIFT A1 by R4.L;\n\t"
00103    
00104             "R2 = A0, R3 = A1;\n\t"
00105             "[P1--] = R2;\n\t"
00106             "[P1--] = R3;\n\t"
00107             "P0 += 4;\n\t"
00108          "LOOP_END pitch%=;\n\t"
00109    : : "m" (xs), "m" (x), "m" (ac32top), "m" (N_lag), "m" (lag_1), "m" (nshift)
00110    : "A0", "A1", "P0", "P1", "P2", "P3", "P4", "R0", "R1", "R2", "R3", "R4", "I0", "I1", "L0", "L1", "B0", "B1", "memory"
00111    );
00112    d=0;
00113    for (j=0;j<n;j++)
00114    {
00115       d = ADD32(d,SHR32(MULT16_16(x[j],x[j]), shift));
00116    }
00117    ac32[0] = d;
00118    
00119    for (i=0;i<lag;i++)
00120    {
00121       d=0;
00122       for (j=i;j<lag_1;j++)
00123       {
00124          d = ADD32(d,SHR32(MULT16_16(x[j],x[j-i]), shift));
00125       }
00126       if (i)
00127          ac32[i] += d;
00128       ac[i] = SHR32(ac32[i], ac_shift);
00129    }
00130 }
00131