Initial import.

1 files changed, 201 insertions, 0 deletions

diff --git a/src/libspeex/lpc.c b/src/libspeex/lpc.c
new file mode 100644
index 0000000..fd5d382
--- /dev/null
+++ b/src/libspeex/lpc.c
@@ -0,0 +1,201 @@
+/*
+  Copyright 1992, 1993, 1994 by Jutta Degener and Carsten Bormann,
+  Technische Universitaet Berlin
+
+  Any use of this software is permitted provided that this notice is not
+  removed and that neither the authors nor the Technische Universitaet Berlin
+  are deemed to have made any representations as to the suitability of this
+  software for any purpose nor are held responsible for any defects of
+  this software.  THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
+
+  As a matter of courtesy, the authors request to be informed about uses
+  this software has found, about bugs in this software, and about any
+  improvements that may be of general interest.
+
+  Berlin, 28.11.1994
+  Jutta Degener
+  Carsten Bormann
+
+
+   Code modified by Jean-Marc Valin
+
+   Speex License:
+
+   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 the Xiph.org Foundation nor the names of its
+   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 FOUNDATION 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 "lpc.h"
+
+#ifdef BFIN_ASM
+#include "lpc_bfin.h"
+#endif
+
+/* LPC analysis
+ *
+ * The next two functions calculate linear prediction coefficients
+ * and/or the related reflection coefficients from the first P_MAX+1
+ * values of the autocorrelation function.
+ */
+
+/* Invented by N. Levinson in 1947, modified by J. Durbin in 1959.
+ */
+
+/* returns minimum mean square error    */
+spx_word32_t _spx_lpc(
+spx_coef_t       *lpc, /* out: [0...p-1] LPC coefficients      */
+const spx_word16_t *ac,  /* in:  [0...p] autocorrelation values  */
+int          p
+)
+{
+   int i, j;  
+   spx_word16_t r;
+   spx_word16_t error = ac[0];
+
+   if (ac[0] == 0)
+   {
+      for (i = 0; i < p; i++)
+         lpc[i] = 0;
+      return 0;
+   }
+
+   for (i = 0; i < p; i++) {
+
+      /* Sum up this iteration's reflection coefficient */
+      spx_word32_t rr = NEG32(SHL32(EXTEND32(ac[i + 1]),13));
+      for (j = 0; j < i; j++) 
+         rr = SUB32(rr,MULT16_16(lpc[j],ac[i - j]));
+#ifdef FIXED_POINT
+      r = DIV32_16(rr+PSHR32(error,1),ADD16(error,8));
+#else
+      r = rr/(error+.003*ac[0]);
+#endif
+      /*  Update LPC coefficients and total error */
+      lpc[i] = r;
+      for (j = 0; j < i>>1; j++) 
+      {
+         spx_word16_t tmp  = lpc[j];
+         lpc[j]     = MAC16_16_P13(lpc[j],r,lpc[i-1-j]);
+         lpc[i-1-j] = MAC16_16_P13(lpc[i-1-j],r,tmp);
+      }
+      if (i & 1) 
+         lpc[j] = MAC16_16_P13(lpc[j],lpc[j],r);
+
+      error = SUB16(error,MULT16_16_Q13(r,MULT16_16_Q13(error,r)));
+   }
+   return error;
+}
+
+
+#ifdef FIXED_POINT
+
+/* Compute the autocorrelation
+ *                      ,--,
+ *              ac(i) = >  x(n) * x(n-i)  for all n
+ *                      `--'
+ * for lags between 0 and lag-1, and x == 0 outside 0...n-1
+ */
+
+#ifndef OVERRIDE_SPEEX_AUTOCORR
+void _spx_autocorr(
+const spx_word16_t *x,   /*  in: [0...n-1] samples x   */
+spx_word16_t       *ac,  /* out: [0...lag-1] ac values */
+int          lag, 
+int          n
+)
+{
+   spx_word32_t d;
+   int i, j;
+   spx_word32_t ac0=1;
+   int shift, ac_shift;
+   
+   for (j=0;j<n;j++)
+      ac0 = ADD32(ac0,SHR32(MULT16_16(x[j],x[j]),8));
+   ac0 = ADD32(ac0,n);
+   shift = 8;
+   while (shift && ac0<0x40000000)
+   {
+      shift--;
+      ac0 <<= 1;
+   }
+   ac_shift = 18;
+   while (ac_shift && ac0<0x40000000)
+   {
+      ac_shift--;
+      ac0 <<= 1;
+   }
+   
+   
+   for (i=0;i<lag;i++)
+   {
+      d=0;
+      for (j=i;j<n;j++)
+      {
+         d = ADD32(d,SHR32(MULT16_16(x[j],x[j-i]), shift));
+      }
+      
+      ac[i] = SHR32(d, ac_shift);
+   }
+}
+#endif
+
+
+#else
+
+
+
+/* Compute the autocorrelation
+ *                      ,--,
+ *              ac(i) = >  x(n) * x(n-i)  for all n
+ *                      `--'
+ * for lags between 0 and lag-1, and x == 0 outside 0...n-1
+ */
+void _spx_autocorr(
+const spx_word16_t *x,   /*  in: [0...n-1] samples x   */
+float       *ac,  /* out: [0...lag-1] ac values */
+int          lag, 
+int          n
+)
+{
+   float d;
+   int i;
+   while (lag--) 
+   {
+      for (i = lag, d = 0; i < n; i++) 
+         d += x[i] * x[i-lag];
+      ac[lag] = d;
+   }
+   ac[0] += 10;
+}
+
+#endif
+
+