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Fixed-point version of frac_div32()

--- a/libcelt/plc.c

+++ b/libcelt/plc.c

@@ -4,9 +4,22 @@

 #endif

 #ifdef FIXED_POINT

-#define frac_div(a,b) ((celt_word32)((32768*65535+32767)*(float)(a)/(b)))

+static celt_word32 frac_div32(celt_word32 a, celt_word32 b)

+{

+   celt_word32 rcp, result, rem;

+   while (b<(1<<30))

+   {

+      a = SHL32(a,1);

+      b = SHL32(b,1);

+   }

+   rcp = PSHR32(celt_rcp(ROUND16(b,16)),2);

+   result = SHL32(MULT16_32_Q15(rcp, a),1);

+   rem = a-MULT32_32_Q31(result, b);

+   result += SHL32(MULT16_32_Q15(rcp, rem),1);

+   return result;

+}

 #else

-#define frac_div(a,b) ((float)(a)/(b))

+#define frac_div32(a,b) ((float)(a)/(b))

 #endif

@@ -36,7 +49,7 @@

             rr += MULT32_32_Q31(lpc[j],ac[i - j]);

          rr += SHR32(ac[i + 1],3);

          //r = -RC_SCALING*1.*SHL32(rr,3)/(error+1e-15);

-         r = -frac_div(SHL32(rr,3), error);

+         r = -frac_div32(SHL32(rr,3), error);

          /*  Update LPC coefficients and total error */

          lpc[i] = SHR32(r,3);

          for (j = 0; j < (i+1)>>1; j++)

@@ -49,8 +62,14 @@

          }

          error = error - MULT32_32_Q31(MULT32_32_Q31(r,r),error);

-         if (error<.00001*ac[0])

+         /* Bail out once we get 30 dB gain */

+#ifdef FIXED_POINT

+         if (error<SHR32(ac[0],10))

             break;

+#else

+         if (error<.001*ac[0])

+            break;

+#endif

       }

    }

 #ifdef FIXED_POINT