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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [gcc/] [hwint.c] - Rev 695
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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" #include "diagnostic-core.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 */ /* Compute the absolute value of X. */ HOST_WIDE_INT abs_hwi (HOST_WIDE_INT x) { gcc_checking_assert (x != HOST_WIDE_INT_MIN); return x >= 0 ? x : -x; } /* Compute the absolute value of X as an unsigned type. */ unsigned HOST_WIDE_INT absu_hwi (HOST_WIDE_INT x) { return x >= 0 ? (unsigned HOST_WIDE_INT)x : -(unsigned HOST_WIDE_INT)x; } /* Compute the greatest common divisor of two numbers A and B using Euclid's algorithm. */ HOST_WIDE_INT gcd (HOST_WIDE_INT a, HOST_WIDE_INT b) { HOST_WIDE_INT x, y, z; x = abs_hwi (a); y = abs_hwi (b); while (x > 0) { z = y % x; y = x; x = z; } return y; } /* For X and Y positive integers, return X multiplied by Y and check that the result does not overflow. */ HOST_WIDE_INT pos_mul_hwi (HOST_WIDE_INT x, HOST_WIDE_INT y) { if (x != 0) gcc_checking_assert ((HOST_WIDE_INT_MAX) / x >= y); return x * y; } /* Return X multiplied by Y and check that the result does not overflow. */ HOST_WIDE_INT mul_hwi (HOST_WIDE_INT x, HOST_WIDE_INT y) { gcc_checking_assert (x != HOST_WIDE_INT_MIN && y != HOST_WIDE_INT_MIN); if (x >= 0) { if (y >= 0) return pos_mul_hwi (x, y); return -pos_mul_hwi (x, -y); } if (y >= 0) return -pos_mul_hwi (-x, y); return pos_mul_hwi (-x, -y); } /* Compute the least common multiple of two numbers A and B . */ HOST_WIDE_INT least_common_multiple (HOST_WIDE_INT a, HOST_WIDE_INT b) { return mul_hwi (abs_hwi (a) / gcd (a, b), abs_hwi (b)); }
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