Prepare for radical source tree reorganization. zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 102 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/ieee754/ldbl-128/s_roundevenl.c b/REORG.TODO/sysdeps/ieee754/ldbl-128/s_roundevenl.c
new file mode 100644
index 0000000000..93b895546a
--- /dev/null
+++ b/REORG.TODO/sysdeps/ieee754/ldbl-128/s_roundevenl.c
@@ -0,0 +1,102 @@
+/* Round to nearest integer value, rounding halfway cases to even.
+   ldbl-128 version.
+   Copyright (C) 2016-2017 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 <stdint.h>
+
+#define BIAS 0x3fff
+#define MANT_DIG 113
+#define MAX_EXP (2 * BIAS + 1)
+
+_Float128
+roundevenl (_Float128 x)
+{
+  uint64_t hx, lx, uhx;
+  GET_LDOUBLE_WORDS64 (hx, lx, x);
+  uhx = hx & 0x7fffffffffffffffULL;
+  int exponent = uhx >> (MANT_DIG - 1 - 64);
+  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 + MANT_DIG - 64)
+    {
+      /* Not necessarily an integer; integer bit is in low word.
+	 Locate the bits with exponents 0 and -1.  */
+      int int_pos = (BIAS + MANT_DIG - 1) - exponent;
+      int half_pos = int_pos - 1;
+      uint64_t half_bit = 1ULL << half_pos;
+      uint64_t int_bit = 1ULL << int_pos;
+      if ((lx & (int_bit | (half_bit - 1))) != 0)
+	{
+	  /* Carry into the exponent works correctly.  No need to test
+	     whether HALF_BIT is set.  */
+	  lx += half_bit;
+	  hx += lx < half_bit;
+	}
+      lx &= ~(int_bit - 1);
+    }
+  else if (exponent == BIAS + MANT_DIG - 65)
+    {
+      /* Not necessarily an integer; integer bit is bottom of high
+	 word, half bit is top of low word.  */
+      if (((hx & 1) | (lx & 0x7fffffffffffffffULL)) != 0)
+	{
+	  lx += 0x8000000000000000ULL;
+	  hx += lx < 0x8000000000000000ULL;
+	}
+      lx = 0;
+    }
+  else if (exponent >= BIAS)
+    {
+      /* At least 1; not necessarily an integer, integer bit and half
+	 bit are in the high word.  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 - 65) - exponent;
+      int half_pos = int_pos - 1;
+      uint64_t half_bit = 1ULL << half_pos;
+      uint64_t int_bit = 1ULL << int_pos;
+      if (((hx & (int_bit | (half_bit - 1))) | lx) != 0)
+	hx += half_bit;
+      hx &= ~(int_bit - 1);
+      lx = 0;
+    }
+  else if (exponent == BIAS - 1 && (uhx > 0x3ffe000000000000ULL || lx != 0))
+    {
+      /* Interval (0.5, 1).  */
+      hx = (hx & 0x8000000000000000ULL) | 0x3fff000000000000ULL;
+      lx = 0;
+    }
+  else
+    {
+      /* Rounds to 0.  */
+      hx &= 0x8000000000000000ULL;
+      lx = 0;
+    }
+  SET_LDOUBLE_WORDS64 (x, hx, lx);
+  return x;
+}