1 files changed, 129 insertions, 0 deletions
diff --git a/newlib/libm/mathfp/s_sqrt.c b/newlib/libm/mathfp/s_sqrt.c
new file mode 100644
index 00000000000..bafbb38b14f
--- /dev/null
+++ b/newlib/libm/mathfp/s_sqrt.c
@@ -0,0 +1,129 @@
+
+/* @(#)z_sqrt.c 1.0 98/08/13 */
+/*****************************************************************
+ * The following routines are coded directly from the algorithms
+ * and coefficients given in "Software Manual for the Elementary
+ * Functions" by William J. Cody, Jr. and William Waite, Prentice
+ * Hall, 1980.
+ *****************************************************************/
+
+/*
+FUNCTION
+        <<sqrt>>, <<sqrtf>>---positive square root
+
+INDEX
+        sqrt
+INDEX
+        sqrtf
+
+ANSI_SYNOPSIS
+        #include <math.h>
+        double sqrt(double <[x]>);
+        float  sqrtf(float <[x]>);
+
+TRAD_SYNOPSIS
+        #include <math.h>
+        double sqrt(<[x]>);
+        float  sqrtf(<[x]>);
+
+DESCRIPTION
+        <<sqrt>> computes the positive square root of the argument.
+
+RETURNS
+        On success, the square root is returned. If <[x]> is real and
+        positive, then the result is positive.  If <[x]> is real and
+        negative, the global value <<errno>> is set to <<EDOM>> (domain error).
+
+
+PORTABILITY
+        <<sqrt>> is ANSI C.  <<sqrtf>> is an extension.
+*/
+
+/******************************************************************
+ * Square Root
+ *
+ * Input:
+ *   x - floating point value
+ *
+ * Output:
+ *   square-root of x
+ *
+ * Description:
+ *   This routine performs floating point square root.
+ *
+ *   The initial approximation is computed as
+ *     y0 = 0.41731 + 0.59016 * f
+ *   where f is a fraction such that x = f * 2^exp.
+ *
+ *   Three Newton iterations in the form of Heron's formula
+ *   are then performed to obtain the final value:
+ *     y[i] = (y[i-1] + f / y[i-1]) / 2, i = 1, 2, 3.
+ *
+ *****************************************************************/
+
+#include "fdlibm.h"
+#include "zmath.h"
+
+#ifndef _DOUBLE_IS_32BITS
+
+double
+_DEFUN (sqrt, (double),
+        double x)
+{
+  double f, y;
+  int exp, i, odd;
+
+  /* Check for special values. */
+  switch (numtest (x))
+    {
+      case NAN:
+        errno = EDOM;
+        return (x);
+      case INF:
+        if (ispos (x))
+          {
+            errno = EDOM;
+            return (z_notanum.d);
+          }
+        else
+          {
+            errno = ERANGE;
+            return (z_infinity.d);
+          }
+    }
+
+  /* Initial checks are performed here. */
+  if (x == 0.0)
+    return (0.0);
+  if (x < 0)
+    {
+      errno = EDOM;
+      return (z_notanum.d);
+    }
+
+  /* Find the exponent and mantissa for the form x = f * 2^exp. */
+  f = frexp (x, &exp);
+
+  odd = exp & 1;
+
+  /* Get the initial approximation. */
+  y = 0.41731 + 0.59016 * f;
+
+  f /= 2.0;
+  /* Calculate the remaining iterations. */
+  for (i = 0; i < 3; ++i)
+    y = y / 2.0 + f / y;
+
+  /* Calculate the final value. */
+  if (odd)
+    {
+      y *= __SQRT_HALF;
+      exp++;
+    }
+  exp >>= 1;
+  y = ldexp (y, exp);
+
+  return (y);
+}
+
+#endif /* _DOUBLE_IS_32BITS */