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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /gcc/hwint.c
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diff --git a/gcc/hwint.c b/gcc/hwint.c
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+/* Operations on HOST_WIDE_INT.
+ Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+ 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+ Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC 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 General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#include "system.h"
+
+#if GCC_VERSION < 3004
+
+/* The functions clz_hwi, ctz_hwi, ffs_hwi, floor_log2 and exact_log2
+ are defined as inline functions in hwint.h if GCC_VERSION >= 3004.
+ The definitions here are used for older versions of GCC and non-GCC
+ bootstrap compilers. */
+
+/* Given X, an unsigned number, return the largest int Y such that 2**Y <= X.
+ If X is 0, return -1. */
+
+int
+floor_log2 (unsigned HOST_WIDE_INT x)
+{
+ int t = 0;
+
+ if (x == 0)
+ return -1;
+
+ if (HOST_BITS_PER_WIDE_INT > 64)
+ if (x >= (unsigned HOST_WIDE_INT) 1 << (t + 64))
+ t += 64;
+ if (HOST_BITS_PER_WIDE_INT > 32)
+ if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 32))
+ t += 32;
+ if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 16))
+ t += 16;
+ if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 8))
+ t += 8;
+ if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 4))
+ t += 4;
+ if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 2))
+ t += 2;
+ if (x >= ((unsigned HOST_WIDE_INT) 1) << (t + 1))
+ t += 1;
+
+ return t;
+}
+
+/* Return the logarithm of X, base 2, considering X unsigned,
+ if X is a power of 2. Otherwise, returns -1. */
+
+int
+exact_log2 (unsigned HOST_WIDE_INT x)
+{
+ if (x != (x & -x))
+ return -1;
+ return floor_log2 (x);
+}
+
+/* Given X, an unsigned number, return the number of least significant bits
+ that are zero. When X == 0, the result is the word size. */
+
+int
+ctz_hwi (unsigned HOST_WIDE_INT x)
+{
+ return x ? floor_log2 (x & -x) : HOST_BITS_PER_WIDE_INT;
+}
+
+/* Similarly for most significant bits. */
+
+int
+clz_hwi (unsigned HOST_WIDE_INT x)
+{
+ return HOST_BITS_PER_WIDE_INT - 1 - floor_log2(x);
+}
+
+/* Similar to ctz_hwi, except that the least significant bit is numbered
+ starting from 1, and X == 0 yields 0. */
+
+int
+ffs_hwi (unsigned HOST_WIDE_INT x)
+{
+ return 1 + floor_log2 (x & -x);
+}
+
+#endif /* GCC_VERSION < 3004 */