From 8a0efa53e44919bcf5ccb1d3353618a82afdf8bc Mon Sep 17 00:00:00 2001
From: Christopher Faylor <me@cgf.cx>
Date: Thu, 17 Feb 2000 19:39:52 +0000
Subject: import newlib-2000-02-17 snapshot

---
 newlib/libm/mathfp/s_pow.c | 146 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 newlib/libm/mathfp/s_pow.c

(limited to 'newlib/libm/mathfp/s_pow.c')

diff --git a/newlib/libm/mathfp/s_pow.c b/newlib/libm/mathfp/s_pow.c
new file mode 100644
index 000000000..7c0a38a20
--- /dev/null
+++ b/newlib/libm/mathfp/s_pow.c
@@ -0,0 +1,146 @@
+
+/* @(#)z_pow.c 1.0 98/08/13 */
+
+/*
+FUNCTION
+        <<pow>>, <<powf>>---x to the power y
+INDEX
+        pow
+INDEX
+        powf
+
+
+ANSI_SYNOPSIS
+        #include <math.h>
+        double pow(double <[x]>, double <[y]>);
+        float pow(float <[x]>, float <[y]>);
+
+TRAD_SYNOPSIS
+        #include <math.h>
+        double pow(<[x]>, <[y]>);
+        double <[x]>, <[y]>;
+
+        float pow(<[x]>, <[y]>);
+        float <[x]>, <[y]>;
+
+DESCRIPTION
+        <<pow>> and <<powf>> calculate <[x]> raised to the exp1.0nt <[y]>.
+        @tex
+        (That is, $x^y$.)
+        @end tex
+
+RETURNS
+        On success, <<pow>> and <<powf>> return the value calculated.
+
+        When the argument values would produce overflow, <<pow>>
+        returns <<HUGE_VAL>> and set <<errno>> to <<ERANGE>>.  If the
+        argument <[x]> passed to <<pow>> or <<powf>> is a negative
+        noninteger, and <[y]> is also not an integer, then <<errno>>
+        is set to <<EDOM>>.  If <[x]> and <[y]> are both 0, then
+        <<pow>> and <<powf>> return <<1>>.
+
+        You can modify error handling for these functions using <<matherr>>.
+
+PORTABILITY
+        <<pow>> is ANSI C. <<powf>> is an extension.  */
+
+#include <float.h>
+#include "fdlibm.h"
+#include "zmath.h"
+
+#ifndef _DOUBLE_IS_32BITS
+
+double pow (double x, double y)
+{
+  double d, t, r = 1.0;
+  int n, k, sign = 0;
+  __uint32_t px;
+
+  GET_HIGH_WORD (px, x);
+
+  k = modf (y, &d);
+  if (k == 0.0) 
+    {
+      if (modf (ldexp (y, -1), &t))
+        sign = 0;
+      else
+        sign = 1; 
+    }
+
+  if (x == 0.0 && y <= 0.0) 
+    errno = EDOM;
+
+  else if ((t = y * log (fabs (x))) >= BIGX) 
+    {
+      errno = ERANGE;
+      if (px & 0x80000000) 
+        {
+          if (!k) 
+            {
+              errno = EDOM;
+              x = 0.0;
+            }
+          else if (sign)
+            x = -z_infinity.d;
+          else
+            x =  z_infinity.d;
+        }
+
+    else 
+      x = z_infinity.d;
+  }
+
+  else if (t < SMALLX)
+    {
+      errno = ERANGE;
+      x = 0.0;
+    }
+
+  else 
+    {
+      if ( k && fabs(d) <= 32767 ) 
+        {
+          n = (int) d;
+
+          if (sign = (n < 0))
+            n = -n;
+
+          while ( n > 0 ) 
+            {
+              if ((unsigned int) n % 2) 
+                r *= x;
+              x *= x;
+              n = (unsigned int) n / 2;
+            }
+
+          if (sign)
+            r = 1.0 / r;
+
+          return r;
+        }
+		
+      else 
+        {
+          if ( px & 0x80000000 ) 
+            {
+              if ( !k ) 
+                {
+                  errno = EDOM;
+                  return 0.0;
+                }
+            }
+
+          x = exp (t);
+
+          if ( sign ) 
+            { 
+              px ^= 0x80000000;
+              SET_HIGH_WORD (x, px);
+            }
+        }
+      }
+
+  return x;
+}
+
+#endif _DOUBLE_IS_32BITS
-- 
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