split out nearbyint, round, trunc from libm/powerpc/s_modf.c

1 files changed, 36 insertions, 0 deletions

diff --git a/libm/powerpc/s_nearbyint.c b/libm/powerpc/s_nearbyint.c
new file mode 100644
index 000000000..f2d7ded35
--- /dev/null
+++ b/libm/powerpc/s_nearbyint.c
@@ -0,0 +1,36 @@
+#include <limits.h>
+#include <math.h>
+
+/*******************************************************************************
+*                                                                              *
+*     The function nearbyint rounds its double argument to integral value      *
+*     according to the current rounding direction and returns the result in    *
+*     double format.  This function does not signal inexact.                   *
+*                                                                              *
+********************************************************************************
+*                                                                              *
+*     This function calls fabs and copysign.		                         *
+*                                                                              *
+*******************************************************************************/
+
+static const double twoTo52      = 4503599627370496.0;
+
+double nearbyint ( double x )
+      {
+	double y;
+	double OldEnvironment;
+
+	y = twoTo52;
+
+	asm ("mffs %0" : "=f" (OldEnvironment));	/* get the environement */
+
+      if ( fabs ( x ) >= y )                          /* huge case is exact */
+            return x;
+      if ( x < 0 ) y = -y;                                   /* negative case */
+      y = ( x + y ) - y;                                    /* force rounding */
+      if ( y == 0.0 )                        /* zero results mirror sign of x */
+            y = copysign ( y, x );
+//	restore old flags
+	asm ("mtfsf 255,%0" : /*NULLOUT*/ : /*IN*/ "f" ( OldEnvironment ));
+      return ( y );
+	}