1 files changed, 70 insertions, 0 deletions
diff --git a/sysdeps/ieee754/flt-32/s_roundevenf.c b/sysdeps/ieee754/flt-32/s_roundevenf.c
new file mode 100644
index 0000000000..90f991d5c4
--- /dev/null
+++ b/sysdeps/ieee754/flt-32/s_roundevenf.c
@@ -0,0 +1,70 @@
+/* Round to nearest integer value, rounding halfway cases to even.
+   flt-32 version.
+   Copyright (C) 2016-2018 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <math_private.h>
+#include <libm-alias-float.h>
+#include <stdint.h>
+
+#define BIAS 0x7f
+#define MANT_DIG 24
+#define MAX_EXP (2 * BIAS + 1)
+
+float
+__roundevenf (float x)
+{
+  uint32_t ix, ux;
+  GET_FLOAT_WORD (ix, x);
+  ux = ix & 0x7fffffff;
+  int exponent = ux >> (MANT_DIG - 1);
+  if (exponent >= BIAS + MANT_DIG - 1)
+    {
+      /* Integer, infinity or NaN.  */
+      if (exponent == MAX_EXP)
+	/* Infinity or NaN; quiet signaling NaNs.  */
+	return x + x;
+      else
+	return x;
+    }
+  else if (exponent >= BIAS)
+    {
+      /* At least 1; not necessarily an integer.  Locate the bits with
+	 exponents 0 and -1 (when the unbiased exponent is 0, the bit
+	 with exponent 0 is implicit, but as the bias is odd it is OK
+	 to take it from the low bit of the exponent).  */
+      int int_pos = (BIAS + MANT_DIG - 1) - exponent;
+      int half_pos = int_pos - 1;
+      uint32_t half_bit = 1U << half_pos;
+      uint32_t int_bit = 1U << int_pos;
+      if ((ix & (int_bit | (half_bit - 1))) != 0)
+	/* Carry into the exponent works correctly.  No need to test
+	   whether HALF_BIT is set.  */
+	ix += half_bit;
+      ix &= ~(int_bit - 1);
+    }
+  else if (exponent == BIAS - 1 && ux > 0x3f000000)
+    /* Interval (0.5, 1).  */
+    ix = (ix & 0x80000000) | 0x3f800000;
+  else
+    /* Rounds to 0.  */
+    ix &= 0x80000000;
+  SET_FLOAT_WORD (x, ix);
+  return x;
+}
+libm_alias_float (__roundeven, roundeven)