1 files changed, 100 insertions, 0 deletions
diff --git a/newlib/libm/mathfp/sf_sqrt.c b/newlib/libm/mathfp/sf_sqrt.c
new file mode 100644
index 000000000..04fa07f6a
--- /dev/null
+++ b/newlib/libm/mathfp/sf_sqrt.c
@@ -0,0 +1,100 @@
+
+/* @(#)z_sqrtf.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.
+ *****************************************************************/
+/******************************************************************
+ * 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"
+
+float
+_DEFUN (sqrtf, (float),
+        float x)
+{
+  float f, y;
+  int exp, i, odd;
+
+  /* Check for special values. */
+  switch (numtestf (x))
+    {
+      case NAN:
+        errno = EDOM;
+        return (x);
+      case INF:
+        if (isposf (x))
+          {
+            errno = EDOM;
+            return (z_notanum_f.f);
+          }
+        else
+          {
+            errno = ERANGE;
+            return (z_infinity_f.f);
+          }
+    } 
+
+  /* Initial checks are performed here. */
+  if (x == 0.0)
+    return (0.0);
+  if (x < 0)
+    {
+      errno = EDOM;
+      return (z_notanum_f.f);
+    }
+
+  /* Find the exponent and mantissa for the form x = f * 2^exp. */
+  f = frexpf (x, &exp);
+  odd = exp & 1;
+
+  /* Get the initial approximation. */
+  y = 0.41731 + 0.59016 * f;
+
+  f *= 0.5;
+  /* Calculate the remaining iterations. */
+  for (i = 0; i < 2; ++i)
+    y = y * 0.5 + f / y;
+
+  /* Calculate the final value. */
+  if (odd)
+    {
+      y *= __SQRT_HALF;
+      exp++;
+    }
+  exp >>= 1;
+  y = ldexpf (y, exp);
+
+  return (y);
+}
+
+#ifdef _DOUBLE_IS_32BITS
+
+double sqrt (double x)
+{
+  return (double) sqrt ((float) x);
+}
+
+#endif /* _DOUBLE_IS_32BITS */