NuttX RTOS

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 123 insertions, 0 deletions

diff --git a/nuttx/lib/lib_rint.c b/nuttx/lib/lib_rint.c
new file mode 100644
index 000000000..f747eea86
--- /dev/null
+++ b/nuttx/lib/lib_rint.c
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+/************************************************************
+ * lib_rint.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name Gregory Nutt nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Compilation Switches
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <sys/types.h>
+#include <stdlib.h>
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Type Declarations
+ ************************************************************/
+
+/************************************************************
+ * Private Function Prototypes
+ ************************************************************/
+
+/**********************************************************
+ * Global Constant Data
+ **********************************************************/
+
+/************************************************************
+ * Global Variables
+ ************************************************************/
+
+/**********************************************************
+ * Private Constant Data
+ **********************************************************/
+
+/************************************************************
+ * Private Variables
+ ************************************************************/
+
+double rint(double x)
+{
+  double retValue;
+
+/* If the current rounding mode rounds toward negative
+ * infinity, rint() is identical to floor().  If the current
+ * rounding mode rounds toward positive infinity, rint() is
+ * identical to ceil(). */
+#if ((defined(FP_ROUND_POSITIVE)) && (FP_ROUNDING_POSITIVE != 0))
+  retValue = ceil(x);
+
+#elif ((defined(FP_ROUND_NEGATIVE)) && (FP_ROUNDING_NEGATIVE != 0))
+  retValue = floor(x);
+
+#else
+
+  /* In the default rounding mode (round to nearest), rint(x) is the
+   * integer nearest x with the additional stipulation that if
+   * |rint(x)-x|=1/2, then rint(x) is even. */
+
+  long dwInteger = (long)x;
+  double fRemainder = x - (double)dwInteger;
+
+  if (x < 0.0) {
+
+    /* fRemainder should be in range 0 .. -1 */
+    if (fRemainder == -0.5)
+      dwInteger = ((dwInteger+1)&~1);
+    else if (fRemainder < -0.5) {
+      dwInteger--;
+
+    } /* end if */
+  } /* end if */
+  else {
+
+    /* fRemainder should be in range 0 .. 1 */
+    if (fRemainder == 0.5)
+      dwInteger = ((dwInteger+1)&~1);
+    else  if (fRemainder > 0.5) {
+      dwInteger++;
+
+    } /* end if */
+  } /* end else */
+
+  retValue = (double)dwInteger;
+#endif
+
+  return retValue;
+}