modify nuttx bug of lack of files

2021-06-11 11:25:07 +08:00
parent 4a7f51a5e9
commit 6d0f2ca39a
6752 changed files with 1528133 additions and 0 deletions
@@ -0,0 +1,91 @@
+/****************************************************************************
+ * libs/libc/math/lib_asinf.c
+ *
+ * This file is a part of NuttX:
+ *
+ *   Copyright (C) 2012, 2016 Gregory Nutt. All rights reserved.
+ *   Ported by: Darcy Gong
+ *
+ * It derives from the Rhombus OS math library by Nick Johnson which has
+ * a compatibile, MIT-style license:
+ *
+ * Copyright (C) 2009-2011 Nick Johnson <nickbjohnson4224 at gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <math.h>
+#include <float.h>
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/* This lib uses Newton's method to approximate asin(x).  Newton's Method
+ * converges very slowly for x close to 1.  We can accelerate convergence
+ * with the following identy:  asin(x)=Sign(x)*(Pi/2-asin(sqrt(1-x^2)))
+ */
+
+static float asinf_aux(float x)
+{
+  double y;
+  float y_sin;
+  float y_cos;
+
+  y = 0.0;
+  y_sin = 0.0F;
+
+  while (fabsf(y_sin - x) > FLT_EPSILON)
+    {
+      y_cos = cosf(y);
+      y -= ((double)y_sin - (double)x) / (double)y_cos;
+      y_sin = sinf(y);
+    }
+
+  return y;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+float asinf(float x)
+{
+  float y;
+
+  /* Verify that the input value is in the domain of the function */
+
+  if (x < -1.0F || x > 1.0F || isnan(x))
+    {
+      return NAN_F;
+    }
+
+  /* if x is > sqrt(2), use identity for faster convergence */
+
+  if (fabsf(x) > 0.71F)
+    {
+      y = M_PI_2_F - asinf_aux(sqrtf(1.0F - x * x));
+      y = copysignf(y, x);
+    }
+  else
+    {
+      y = asinf_aux(x);
+    }
+
+  return y;
+}