| /* |
| * Copyright (c) 2003-2005 The Regents of The University of Michigan |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer; |
| * redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution; |
| * neither the name of the copyright holders nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #ifndef __BASE_BITFIELD_HH__ |
| #define __BASE_BITFIELD_HH__ |
| |
| #include "sim/host.hh" |
| |
| /** |
| * Generate a 64-bit mask of 'nbits' 1s, right justified. |
| */ |
| inline uint64_t |
| mask(int nbits) |
| { |
| return (nbits == 64) ? (uint64_t)-1LL : (1ULL << nbits) - 1; |
| } |
| |
| |
| /** |
| * Extract the bitfield from position 'first' to 'last' (inclusive) |
| * from 'val' and right justify it. MSB is numbered 63, LSB is 0. |
| */ |
| template <class T> |
| inline |
| T |
| bits(T val, int first, int last) |
| { |
| int nbits = first - last + 1; |
| return (val >> last) & mask(nbits); |
| } |
| |
| /** |
| * Sign-extend an N-bit value to 64 bits. |
| */ |
| template <int N> |
| inline |
| int64_t |
| sext(uint64_t val) |
| { |
| int sign_bit = bits(val, N-1, N-1); |
| return sign_bit ? (val | ~mask(N)) : val; |
| } |
| |
| #endif // __BASE_BITFIELD_HH__ |