[Opus] Update to v1.2.1

third_party/opus/src/celt/mathops.h

 /* Copyright (c) 2002-2008 Jean-Marc Valin
    Copyright (c) 2007-2008 CSIRO
    Copyright (c) 2007-2009 Xiph.Org Foundation
    Written by Jean-Marc Valin */
 /**
    @file mathops.h
    @brief Various math functions
 */
 /*
    Redistribution and use in source and binary forms, with or without
@@ skipping 20 matching lines @@
    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 #ifndef MATHOPS_H
 #define MATHOPS_H
 
 #include "arch.h"
 #include "entcode.h"
 #include "os_support.h"
 
+#define PI 3.141592653f
+
 /* Multiplies two 16-bit fractional values. Bit-exactness of this macro is important */
 #define FRAC_MUL16(a,b) ((16384+((opus_int32)(opus_int16)(a)*(opus_int16)(b)))>>15)
 
 unsigned isqrt32(opus_uint32 _val);
 
+/* CELT doesn't need it for fixed-point, by analysis.c does. */
+#if !defined(FIXED_POINT) || defined(ANALYSIS_C)
+#define cA 0.43157974f
+#define cB 0.67848403f
+#define cC 0.08595542f
+#define cE ((float)PI/2)
+static OPUS_INLINE float fast_atan2f(float y, float x) {
+   float x2, y2;
+   x2 = x*x;
+   y2 = y*y;
+   /* For very small values, we don't care about the answer, so
+      we can just return 0. */
+   if (x2 + y2 < 1e-18f)
+   {
+      return 0;
+   }
+   if(x2<y2){
+      float den = (y2 + cB*x2) * (y2 + cC*x2);
+      return -x*y*(y2 + cA*x2) / den + (y<0 ? -cE : cE);
+   }else{
+      float den = (x2 + cB*y2) * (x2 + cC*y2);
+      return  x*y*(x2 + cA*y2) / den + (y<0 ? -cE : cE) - (x*y<0 ? -cE : cE);
+   }
+}
+#undef cA
+#undef cB
+#undef cC
+#undef cD
+#endif
+
+
 #ifndef OVERRIDE_CELT_MAXABS16
 static OPUS_INLINE opus_val32 celt_maxabs16(const opus_val16 *x, int len)
 {
    int i;
    opus_val16 maxval = 0;
    opus_val16 minval = 0;
    for (i=0;i<len;i++)
    {
       maxval = MAX16(maxval, x[i]);
       minval = MIN16(minval, x[i]);
@@ skipping 17 matching lines @@
    return MAX32(maxval, -minval);
 }
 #else
 #define celt_maxabs32(x,len) celt_maxabs16(x,len)
 #endif
 #endif
 
 
 #ifndef FIXED_POINT
 
-#define PI 3.141592653f
 #define celt_sqrt(x) ((float)sqrt(x))
 #define celt_rsqrt(x) (1.f/celt_sqrt(x))
 #define celt_rsqrt_norm(x) (celt_rsqrt(x))
 #define celt_cos_norm(x) ((float)cos((.5f*PI)*(x)))
 #define celt_rcp(x) (1.f/(x))
 #define celt_div(a,b) ((a)/(b))
 #define frac_div32(a,b) ((float)(a)/(b))
 
 #ifdef FLOAT_APPROX
 
@@ skipping 155 matching lines @@
       opus_val32 arg;
       arg = celt_div(SHL32(EXTEND32(x),15),y);
       if (arg >= 32767)
          arg = 32767;
       return 25736-SHR16(celt_atan01(EXTRACT16(arg)),1);
    }
 }
 
 #endif /* FIXED_POINT */
 #endif /* MATHOPS_H */