1 files changed, 83 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc64/fpu/s_llroundf.c b/sysdeps/powerpc/powerpc64/fpu/s_llroundf.c
new file mode 100644
index 0000000000..160c00ed6f
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/fpu/s_llroundf.c
@@ -0,0 +1,83 @@
+/* Round to nearest integer.  PowerPC64 version.
+   Copyright (C) 2019 Free Software Foundation, Inc.
+   This file is part of the GNU C Library
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#define NO_MATH_REDIRECT
+#define lroundf __redirect_llround
+#define __lroundf __redirect___lround
+#include <math.h>
+#undef lroundf
+#undef __lroundf
+#include <libm-alias-float.h>
+#include <math-barriers.h>
+
+long long int
+__llroundf (float x)
+{
+#ifdef _ARCH_PWR5X
+  double r = __builtin_round (x);
+  /* Prevent gcc from calling llround directly when compiled with
+     -fno-math-errno by inserting a barrier.  */
+  math_opt_barrier (r);
+  return r;
+#else
+   /* IEEE 1003.1 llroundf function.  IEEE specifies "roundf to the nearest
+      integer value, rounding halfway cases away from zero, regardless of
+      the current rounding mode."  However PowerPC Architecture defines
+      "roundf to Nearest" as "Choose the best approximation. In case of a
+      tie, choose the one that is even (least significant bit o).".
+      So we can't use the PowerPC "round to Nearest" mode. Instead we set
+      "round toward Zero" mode and round by adding +-0.5 before rounding
+      to the integer value.
+
+      It is necessary to detect when x is (+-)0x1.fffffffffffffp-2
+      because adding +-0.5 in this case will cause an erroneous shift,
+      carry and round.  We simply return 0 if 0.5 > x > -0.5.  Likewise
+      if x is and odd number between +-(2^23 and 2^24-1) a shift and
+      carry will erroneously round if biased with +-0.5.  Therefore if x
+      is greater/less than +-2^23 we don't need to bias the number with
+      +-0.5.  */
+
+  float ax = fabsf (x);
+
+  if (ax < 0.5f)
+    return 0;
+
+  if (ax < 0x1p+23f)
+    {
+      /* Test whether an integer to avoid spurious "inexact".  */
+      float t = ax + 0x1p+23f;
+      t = t - 0x1p+23f;
+      if (ax != t)
+	{
+	  ax = ax + 0.5f;
+	  if (x < 0.0f)
+	    ax = -fabs (ax);
+	  x = ax;
+	}
+    }
+
+  long int ret;
+  __asm__ ("fctidz %0, %1" : "=d" (ret) : "d" (x));
+  return ret;
+#endif
+}
+#ifndef __llroundf
+strong_alias (__llroundf, __lroundf)
+libm_alias_float (__llround, lround)
+libm_alias_float (__llround, llround)
+#endif