upload sdk

git-svn-id: svn://kolibrios.org@4349 a494cfbc-eb01-0410-851d-a64ba20cac60

contrib/sdk/sources/newlib/math/s_round.c

@@ -0,0 +1,115 @@
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice 
+ * is preserved.
+ * ====================================================
+ */
+/*
+FUNCTION
+<<round>>, <<roundf>>--round to integer, to nearest
+INDEX
+	round
+INDEX
+	roundf
+
+ANSI_SYNOPSIS
+	#include <math.h>
+	double round(double <[x]>);
+	float roundf(float <[x]>);
+
+DESCRIPTION
+	The <<round>> functions round their argument to the nearest integer
+	value in floating-point format, rounding halfway cases away from zero,
+	regardless of the current rounding direction.  (While the "inexact"
+	floating-point exception behavior is unspecified by the C standard, the
+	<<round>> functions are written so that "inexact" is not raised if the
+	result does not equal the argument, which behavior is as recommended by
+	IEEE 754 for its related functions.)
+
+RETURNS
+<[x]> rounded to an integral value.
+
+PORTABILITY
+ANSI C, POSIX
+
+SEEALSO
+<<nearbyint>>, <<rint>>
+
+*/
+
+#include "fdlibm.h"
+
+#ifndef _DOUBLE_IS_32BITS
+
+#ifdef __STDC__
+	double round(double x)
+#else
+	double round(x)
+	double x;
+#endif
+{
+  /* Most significant word, least significant word. */
+  __int32_t msw, exponent_less_1023;
+  __uint32_t lsw;
+
+  EXTRACT_WORDS(msw, lsw, x);
+
+  /* Extract exponent field. */
+  exponent_less_1023 = ((msw & 0x7ff00000) >> 20) - 1023;
+
+  if (exponent_less_1023 < 20)
+    {
+      if (exponent_less_1023 < 0)
+        {
+          msw &= 0x80000000;
+          if (exponent_less_1023 == -1)
+            /* Result is +1.0 or -1.0. */
+            msw |= (1023 << 20);
+          lsw = 0;
+        }
+      else
+        {
+          __uint32_t exponent_mask = 0x000fffff >> exponent_less_1023;
+          if ((msw & exponent_mask) == 0 && lsw == 0)
+            /* x in an integral value. */
+            return x;
+
+          msw += 0x00080000 >> exponent_less_1023;
+          msw &= ~exponent_mask;
+          lsw = 0;
+        }
+    }
+  else if (exponent_less_1023 > 51)
+    {
+      if (exponent_less_1023 == 1024)
+        /* x is NaN or infinite. */
+        return x + x;
+      else
+        return x;
+    }
+  else
+    {
+      __uint32_t exponent_mask = 0xffffffff >> (exponent_less_1023 - 20);
+      __uint32_t tmp;
+
+      if ((lsw & exponent_mask) == 0)
+        /* x is an integral value. */
+        return x;
+
+      tmp = lsw + (1 << (51 - exponent_less_1023));
+      if (tmp < lsw)
+        msw += 1;
+      lsw = tmp;
+
+      lsw &= ~exponent_mask;
+    }
+  INSERT_WORDS(x, msw, lsw);
+
+  return x;
+}
+
+#endif /* _DOUBLE_IS_32BITS */