bitfield.hh revision 4661
12SN/A/* 21762SN/A * Copyright (c) 2003-2005 The Regents of The University of Michigan 32SN/A * All rights reserved. 42SN/A * 52SN/A * Redistribution and use in source and binary forms, with or without 62SN/A * modification, are permitted provided that the following conditions are 72SN/A * met: redistributions of source code must retain the above copyright 82SN/A * notice, this list of conditions and the following disclaimer; 92SN/A * redistributions in binary form must reproduce the above copyright 102SN/A * notice, this list of conditions and the following disclaimer in the 112SN/A * documentation and/or other materials provided with the distribution; 122SN/A * neither the name of the copyright holders nor the names of its 132SN/A * contributors may be used to endorse or promote products derived from 142SN/A * this software without specific prior written permission. 152SN/A * 162SN/A * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 172SN/A * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 182SN/A * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 192SN/A * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 202SN/A * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 212SN/A * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 222SN/A * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 232SN/A * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 242SN/A * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 252SN/A * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 262SN/A * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 272665Ssaidi@eecs.umich.edu * 282665Ssaidi@eecs.umich.edu * Authors: Steve Reinhardt 292665Ssaidi@eecs.umich.edu * Nathan Binkert 302SN/A */ 312SN/A 321112SN/A#ifndef __BASE_BITFIELD_HH__ 331112SN/A#define __BASE_BITFIELD_HH__ 342SN/A 353386Sgblack@eecs.umich.edu#include <inttypes.h> 362SN/A 372SN/A/** 382SN/A * Generate a 64-bit mask of 'nbits' 1s, right justified. 392SN/A */ 402SN/Ainline uint64_t 412SN/Amask(int nbits) 422SN/A{ 432SN/A return (nbits == 64) ? (uint64_t)-1LL : (1ULL << nbits) - 1; 442SN/A} 452SN/A 462SN/A 474070Ssaidi@eecs.umich.edu 482SN/A/** 492SN/A * Extract the bitfield from position 'first' to 'last' (inclusive) 502SN/A * from 'val' and right justify it. MSB is numbered 63, LSB is 0. 512SN/A */ 522SN/Atemplate <class T> 532SN/Ainline 542SN/AT 552SN/Abits(T val, int first, int last) 562SN/A{ 572SN/A int nbits = first - last + 1; 582SN/A return (val >> last) & mask(nbits); 592SN/A} 602SN/A 612SN/A/** 624661Sksewell@umich.edu * Extract the bit from this position from 'val' and right justify it. 634661Sksewell@umich.edu */ 644661Sksewell@umich.edutemplate <class T> 654661Sksewell@umich.eduinline 664661Sksewell@umich.eduT 674661Sksewell@umich.edubits(T val, int bit) 684661Sksewell@umich.edu{ 694661Sksewell@umich.edu return bits(val, bit, bit); 704661Sksewell@umich.edu} 714661Sksewell@umich.edu 724661Sksewell@umich.edu/** 733814Ssaidi@eecs.umich.edu * Mask off the given bits in place like bits() but without shifting. 743814Ssaidi@eecs.umich.edu * msb = 63, lsb = 0 753814Ssaidi@eecs.umich.edu */ 763814Ssaidi@eecs.umich.edutemplate <class T> 773814Ssaidi@eecs.umich.eduinline 783814Ssaidi@eecs.umich.eduT 793814Ssaidi@eecs.umich.edumbits(T val, int first, int last) 803814Ssaidi@eecs.umich.edu{ 813814Ssaidi@eecs.umich.edu return val & (mask(first+1) & ~mask(last)); 823814Ssaidi@eecs.umich.edu} 833814Ssaidi@eecs.umich.edu 844070Ssaidi@eecs.umich.eduinline uint64_t 854070Ssaidi@eecs.umich.edumask(int first, int last) 864070Ssaidi@eecs.umich.edu{ 874070Ssaidi@eecs.umich.edu return mbits((uint64_t)-1LL, first, last); 884070Ssaidi@eecs.umich.edu} 894070Ssaidi@eecs.umich.edu 903814Ssaidi@eecs.umich.edu/** 912SN/A * Sign-extend an N-bit value to 64 bits. 922SN/A */ 932SN/Atemplate <int N> 942SN/Ainline 952SN/Aint64_t 962SN/Asext(uint64_t val) 972SN/A{ 982SN/A int sign_bit = bits(val, N-1, N-1); 992SN/A return sign_bit ? (val | ~mask(N)) : val; 1002SN/A} 1012SN/A 1023422Sgblack@eecs.umich.edu/** 1033422Sgblack@eecs.umich.edu * Return val with bits first to last set to bit_val 1043422Sgblack@eecs.umich.edu */ 1053422Sgblack@eecs.umich.edutemplate <class T, class B> 1063422Sgblack@eecs.umich.eduinline 1073422Sgblack@eecs.umich.eduT 1083422Sgblack@eecs.umich.eduinsertBits(T val, int first, int last, B bit_val) 1093422Sgblack@eecs.umich.edu{ 1104425Ssaidi@eecs.umich.edu T t_bit_val = bit_val; 1113422Sgblack@eecs.umich.edu T bmask = mask(first - last + 1) << last; 1124425Ssaidi@eecs.umich.edu return ((t_bit_val << last) & bmask) | (val & ~bmask); 1133422Sgblack@eecs.umich.edu} 1143422Sgblack@eecs.umich.edu 1153422Sgblack@eecs.umich.edu/** 1164661Sksewell@umich.edu * Overloaded for access to only one bit in value 1174661Sksewell@umich.edu */ 1184661Sksewell@umich.edutemplate <class T, class B> 1194661Sksewell@umich.eduinline 1204661Sksewell@umich.eduT 1214661Sksewell@umich.eduinsertBits(T val, int bit, B bit_val) 1224661Sksewell@umich.edu{ 1234661Sksewell@umich.edu return insertBits(val, bit, bit, bit_val); 1244661Sksewell@umich.edu} 1254661Sksewell@umich.edu 1264661Sksewell@umich.edu/** 1273422Sgblack@eecs.umich.edu * A convenience function to replace bits first to last of val with bit_val 1283422Sgblack@eecs.umich.edu * in place. 1293422Sgblack@eecs.umich.edu */ 1303422Sgblack@eecs.umich.edutemplate <class T, class B> 1313422Sgblack@eecs.umich.eduinline 1323422Sgblack@eecs.umich.eduvoid 1333422Sgblack@eecs.umich.edureplaceBits(T& val, int first, int last, B bit_val) 1343422Sgblack@eecs.umich.edu{ 1353422Sgblack@eecs.umich.edu val = insertBits(val, first, last, bit_val); 1363422Sgblack@eecs.umich.edu} 1373422Sgblack@eecs.umich.edu 1384661Sksewell@umich.edu/** Overloaded function to allow to access only 1 bit*/ 1394661Sksewell@umich.edutemplate <class T, class B> 1404661Sksewell@umich.eduinline 1414661Sksewell@umich.eduvoid 1424661Sksewell@umich.edureplaceBits(T& val, int bit, B bit_val) 1434661Sksewell@umich.edu{ 1444661Sksewell@umich.edu val = insertBits(val, bit, bit, bit_val); 1454661Sksewell@umich.edu} 1464103Ssaidi@eecs.umich.edu/** 1474103Ssaidi@eecs.umich.edu * Returns the bit position of the MSB that is set in the input 1484103Ssaidi@eecs.umich.edu */ 1494103Ssaidi@eecs.umich.eduinline 1504103Ssaidi@eecs.umich.eduint 1514103Ssaidi@eecs.umich.edufindMsbSet(uint64_t val) { 1524103Ssaidi@eecs.umich.edu int msb = 0; 1534103Ssaidi@eecs.umich.edu if (!val) 1544103Ssaidi@eecs.umich.edu return 0; 1554244Ssaidi@eecs.umich.edu if (bits(val, 63,32)) { msb += 32; val >>= 32; } 1564244Ssaidi@eecs.umich.edu if (bits(val, 31,16)) { msb += 16; val >>= 16; } 1574244Ssaidi@eecs.umich.edu if (bits(val, 15,8)) { msb += 8; val >>= 8; } 1584244Ssaidi@eecs.umich.edu if (bits(val, 7,4)) { msb += 4; val >>= 4; } 1594244Ssaidi@eecs.umich.edu if (bits(val, 3,2)) { msb += 2; val >>= 2; } 1604244Ssaidi@eecs.umich.edu if (bits(val, 1,1)) { msb += 1; } 1614103Ssaidi@eecs.umich.edu return msb; 1624103Ssaidi@eecs.umich.edu} 1634103Ssaidi@eecs.umich.edu 1644259Sgblack@eecs.umich.edu// The following implements the BitUnion system of defining bitfields 1654262Sgblack@eecs.umich.edu//on top of an underlying class. This is done through the pervasive use of 1664259Sgblack@eecs.umich.edu//both named and unnamed unions which all contain the same actual storage. 1674259Sgblack@eecs.umich.edu//Since they're unioned with each other, all of these storage locations 1684259Sgblack@eecs.umich.edu//overlap. This allows all of the bitfields to manipulate the same data 1694262Sgblack@eecs.umich.edu//without having to have access to each other. More details are provided with the 1704259Sgblack@eecs.umich.edu//individual components. 1714259Sgblack@eecs.umich.edu 1724259Sgblack@eecs.umich.edu//This namespace is for classes which implement the backend of the BitUnion 1734262Sgblack@eecs.umich.edu//stuff. Don't use any of these directly, except for the Bitfield classes in 1744262Sgblack@eecs.umich.edu//the *BitfieldTypes class(es). 1754258Sgblack@eecs.umich.edunamespace BitfieldBackend 1764257Sgblack@eecs.umich.edu{ 1774259Sgblack@eecs.umich.edu //A base class for all bitfields. It instantiates the actual storage, 1784259Sgblack@eecs.umich.edu //and provides getBits and setBits functions for manipulating it. The 1794259Sgblack@eecs.umich.edu //Data template parameter is type of the underlying storage. 1804258Sgblack@eecs.umich.edu template<class Data> 1814258Sgblack@eecs.umich.edu class BitfieldBase 1824258Sgblack@eecs.umich.edu { 1834258Sgblack@eecs.umich.edu protected: 1844258Sgblack@eecs.umich.edu Data __data; 1854103Ssaidi@eecs.umich.edu 1864259Sgblack@eecs.umich.edu //This function returns a range of bits from the underlying storage. 1874259Sgblack@eecs.umich.edu //It relies on the "bits" function above. It's the user's 1884259Sgblack@eecs.umich.edu //responsibility to make sure that there is a properly overloaded 1894259Sgblack@eecs.umich.edu //version of this function for whatever type they want to overlay. 1904258Sgblack@eecs.umich.edu inline uint64_t 1914275Sgblack@eecs.umich.edu getBits(int first, int last) const 1924258Sgblack@eecs.umich.edu { 1934258Sgblack@eecs.umich.edu return bits(__data, first, last); 1944258Sgblack@eecs.umich.edu } 1954258Sgblack@eecs.umich.edu 1964259Sgblack@eecs.umich.edu //Similar to the above, but for settings bits with replaceBits. 1974258Sgblack@eecs.umich.edu inline void 1984258Sgblack@eecs.umich.edu setBits(int first, int last, uint64_t val) 1994258Sgblack@eecs.umich.edu { 2004258Sgblack@eecs.umich.edu replaceBits(__data, first, last, val); 2014258Sgblack@eecs.umich.edu } 2024258Sgblack@eecs.umich.edu }; 2034258Sgblack@eecs.umich.edu 2044262Sgblack@eecs.umich.edu //This class contains all the "regular" bitfield classes. It is inherited 2054262Sgblack@eecs.umich.edu //by all BitUnions which give them access to those types. 2064262Sgblack@eecs.umich.edu template<class Type> 2074262Sgblack@eecs.umich.edu class RegularBitfieldTypes 2084257Sgblack@eecs.umich.edu { 2094262Sgblack@eecs.umich.edu protected: 2104262Sgblack@eecs.umich.edu //This class implements ordinary bitfields, that is a span of bits 2114262Sgblack@eecs.umich.edu //who's msb is "first", and who's lsb is "last". 2124262Sgblack@eecs.umich.edu template<int first, int last=first> 2134262Sgblack@eecs.umich.edu class Bitfield : public BitfieldBase<Type> 2144262Sgblack@eecs.umich.edu { 2154262Sgblack@eecs.umich.edu public: 2164274Sgblack@eecs.umich.edu operator uint64_t () const 2174262Sgblack@eecs.umich.edu { 2184262Sgblack@eecs.umich.edu return this->getBits(first, last); 2194262Sgblack@eecs.umich.edu } 2204261Sgblack@eecs.umich.edu 2214274Sgblack@eecs.umich.edu uint64_t 2224274Sgblack@eecs.umich.edu operator=(const uint64_t _data) 2234262Sgblack@eecs.umich.edu { 2244262Sgblack@eecs.umich.edu this->setBits(first, last, _data); 2254262Sgblack@eecs.umich.edu return _data; 2264262Sgblack@eecs.umich.edu } 2274262Sgblack@eecs.umich.edu }; 2284262Sgblack@eecs.umich.edu 2294262Sgblack@eecs.umich.edu //A class which specializes the above so that it can only be read 2304262Sgblack@eecs.umich.edu //from. This is accomplished explicitly making sure the assignment 2314262Sgblack@eecs.umich.edu //operator is blocked. The conversion operator is carried through 2324262Sgblack@eecs.umich.edu //inheritance. This will unfortunately need to be copied into each 2334262Sgblack@eecs.umich.edu //bitfield type due to limitations with how templates work 2344262Sgblack@eecs.umich.edu template<int first, int last=first> 2354262Sgblack@eecs.umich.edu class BitfieldRO : public Bitfield<first, last> 2364258Sgblack@eecs.umich.edu { 2374262Sgblack@eecs.umich.edu private: 2384274Sgblack@eecs.umich.edu uint64_t 2394274Sgblack@eecs.umich.edu operator=(const uint64_t _data); 2404262Sgblack@eecs.umich.edu }; 2414262Sgblack@eecs.umich.edu 2424262Sgblack@eecs.umich.edu //Similar to the above, but only allows writing. 2434262Sgblack@eecs.umich.edu template<int first, int last=first> 2444262Sgblack@eecs.umich.edu class BitfieldWO : public Bitfield<first, last> 2454262Sgblack@eecs.umich.edu { 2464262Sgblack@eecs.umich.edu private: 2474274Sgblack@eecs.umich.edu operator uint64_t () const; 2484262Sgblack@eecs.umich.edu 2494262Sgblack@eecs.umich.edu public: 2504274Sgblack@eecs.umich.edu using Bitfield<first, last>::operator=; 2514274Sgblack@eecs.umich.edu }; 2524274Sgblack@eecs.umich.edu }; 2534274Sgblack@eecs.umich.edu 2544274Sgblack@eecs.umich.edu //This class contains all the "regular" bitfield classes. It is inherited 2554274Sgblack@eecs.umich.edu //by all BitUnions which give them access to those types. 2564274Sgblack@eecs.umich.edu template<class Type> 2574274Sgblack@eecs.umich.edu class SignedBitfieldTypes 2584274Sgblack@eecs.umich.edu { 2594274Sgblack@eecs.umich.edu protected: 2604274Sgblack@eecs.umich.edu //This class implements ordinary bitfields, that is a span of bits 2614274Sgblack@eecs.umich.edu //who's msb is "first", and who's lsb is "last". 2624274Sgblack@eecs.umich.edu template<int first, int last=first> 2634274Sgblack@eecs.umich.edu class SignedBitfield : public BitfieldBase<Type> 2644274Sgblack@eecs.umich.edu { 2654274Sgblack@eecs.umich.edu public: 2664274Sgblack@eecs.umich.edu operator int64_t () const 2674262Sgblack@eecs.umich.edu { 2684274Sgblack@eecs.umich.edu return sext<first - last + 1>(this->getBits(first, last)); 2694274Sgblack@eecs.umich.edu } 2704274Sgblack@eecs.umich.edu 2714274Sgblack@eecs.umich.edu int64_t 2724274Sgblack@eecs.umich.edu operator=(const int64_t _data) 2734274Sgblack@eecs.umich.edu { 2744274Sgblack@eecs.umich.edu this->setBits(first, last, _data); 2754274Sgblack@eecs.umich.edu return _data; 2764274Sgblack@eecs.umich.edu } 2774274Sgblack@eecs.umich.edu }; 2784274Sgblack@eecs.umich.edu 2794274Sgblack@eecs.umich.edu //A class which specializes the above so that it can only be read 2804274Sgblack@eecs.umich.edu //from. This is accomplished explicitly making sure the assignment 2814274Sgblack@eecs.umich.edu //operator is blocked. The conversion operator is carried through 2824274Sgblack@eecs.umich.edu //inheritance. This will unfortunately need to be copied into each 2834274Sgblack@eecs.umich.edu //bitfield type due to limitations with how templates work 2844274Sgblack@eecs.umich.edu template<int first, int last=first> 2854274Sgblack@eecs.umich.edu class SignedBitfieldRO : public SignedBitfield<first, last> 2864274Sgblack@eecs.umich.edu { 2874274Sgblack@eecs.umich.edu private: 2884274Sgblack@eecs.umich.edu int64_t 2894274Sgblack@eecs.umich.edu operator=(const int64_t _data); 2904274Sgblack@eecs.umich.edu }; 2914274Sgblack@eecs.umich.edu 2924274Sgblack@eecs.umich.edu //Similar to the above, but only allows writing. 2934274Sgblack@eecs.umich.edu template<int first, int last=first> 2944274Sgblack@eecs.umich.edu class SignedBitfieldWO : public SignedBitfield<first, last> 2954274Sgblack@eecs.umich.edu { 2964274Sgblack@eecs.umich.edu private: 2974274Sgblack@eecs.umich.edu operator int64_t () const; 2984274Sgblack@eecs.umich.edu 2994274Sgblack@eecs.umich.edu public: 3004274Sgblack@eecs.umich.edu int64_t operator=(const int64_t _data) 3014274Sgblack@eecs.umich.edu { 3024274Sgblack@eecs.umich.edu *((SignedBitfield<first, last> *)this) = _data; 3034262Sgblack@eecs.umich.edu return _data; 3044262Sgblack@eecs.umich.edu } 3054262Sgblack@eecs.umich.edu }; 3064258Sgblack@eecs.umich.edu }; 3074257Sgblack@eecs.umich.edu 3084262Sgblack@eecs.umich.edu template<class Type> 3094274Sgblack@eecs.umich.edu class BitfieldTypes : public RegularBitfieldTypes<Type>, 3104274Sgblack@eecs.umich.edu public SignedBitfieldTypes<Type> 3114262Sgblack@eecs.umich.edu {}; 3124258Sgblack@eecs.umich.edu 3134259Sgblack@eecs.umich.edu //When a BitUnion is set up, an underlying class is created which holds 3144259Sgblack@eecs.umich.edu //the actual union. This class then inherits from it, and provids the 3154259Sgblack@eecs.umich.edu //implementations for various operators. Setting things up this way 3164259Sgblack@eecs.umich.edu //prevents having to redefine these functions in every different BitUnion 3174259Sgblack@eecs.umich.edu //type. More operators could be implemented in the future, as the need 3184259Sgblack@eecs.umich.edu //arises. 3194258Sgblack@eecs.umich.edu template <class Type, class Base> 3204258Sgblack@eecs.umich.edu class BitUnionOperators : public Base 3214257Sgblack@eecs.umich.edu { 3224258Sgblack@eecs.umich.edu public: 3234274Sgblack@eecs.umich.edu operator Type () const 3244258Sgblack@eecs.umich.edu { 3254258Sgblack@eecs.umich.edu return Base::__data; 3264258Sgblack@eecs.umich.edu } 3274257Sgblack@eecs.umich.edu 3284274Sgblack@eecs.umich.edu Type 3294260Sgblack@eecs.umich.edu operator=(const Type & _data) 3304258Sgblack@eecs.umich.edu { 3314258Sgblack@eecs.umich.edu Base::__data = _data; 3324274Sgblack@eecs.umich.edu return _data; 3334258Sgblack@eecs.umich.edu } 3344257Sgblack@eecs.umich.edu 3354258Sgblack@eecs.umich.edu bool 3364274Sgblack@eecs.umich.edu operator<(const Base & base) const 3374258Sgblack@eecs.umich.edu { 3384258Sgblack@eecs.umich.edu return Base::__data < base.__data; 3394258Sgblack@eecs.umich.edu } 3404257Sgblack@eecs.umich.edu 3414258Sgblack@eecs.umich.edu bool 3424274Sgblack@eecs.umich.edu operator==(const Base & base) const 3434258Sgblack@eecs.umich.edu { 3444258Sgblack@eecs.umich.edu return Base::__data == base.__data; 3454258Sgblack@eecs.umich.edu } 3464258Sgblack@eecs.umich.edu }; 3474258Sgblack@eecs.umich.edu} 3484257Sgblack@eecs.umich.edu 3494259Sgblack@eecs.umich.edu//This macro is a backend for other macros that specialize it slightly. 3504259Sgblack@eecs.umich.edu//First, it creates/extends a namespace "BitfieldUnderlyingClasses" and 3514259Sgblack@eecs.umich.edu//sticks the class which has the actual union in it, which 3524259Sgblack@eecs.umich.edu//BitfieldOperators above inherits from. Putting these classes in a special 3534259Sgblack@eecs.umich.edu//namespace ensures that there will be no collisions with other names as long 3544259Sgblack@eecs.umich.edu//as the BitUnion names themselves are all distinct and nothing else uses 3554259Sgblack@eecs.umich.edu//the BitfieldUnderlyingClasses namespace, which is unlikely. The class itself 3564259Sgblack@eecs.umich.edu//creates a typedef of the "type" parameter called __DataType. This allows 3574259Sgblack@eecs.umich.edu//the type to propagate outside of the macro itself in a controlled way. 3584259Sgblack@eecs.umich.edu//Finally, the base storage is defined which BitfieldOperators will refer to 3594259Sgblack@eecs.umich.edu//in the operators it defines. This macro is intended to be followed by 3604259Sgblack@eecs.umich.edu//bitfield definitions which will end up inside it's union. As explained 3614259Sgblack@eecs.umich.edu//above, these is overlayed the __data member in its entirety by each of the 3624259Sgblack@eecs.umich.edu//bitfields which are defined in the union, creating shared storage with no 3634259Sgblack@eecs.umich.edu//overhead. 3644257Sgblack@eecs.umich.edu#define __BitUnion(type, name) \ 3654258Sgblack@eecs.umich.edu namespace BitfieldUnderlyingClasses \ 3664258Sgblack@eecs.umich.edu { \ 3674258Sgblack@eecs.umich.edu class name; \ 3684258Sgblack@eecs.umich.edu } \ 3694262Sgblack@eecs.umich.edu class BitfieldUnderlyingClasses::name : \ 3704262Sgblack@eecs.umich.edu public BitfieldBackend::BitfieldTypes<type> \ 3714262Sgblack@eecs.umich.edu { \ 3724257Sgblack@eecs.umich.edu public: \ 3734257Sgblack@eecs.umich.edu typedef type __DataType; \ 3744257Sgblack@eecs.umich.edu union { \ 3754257Sgblack@eecs.umich.edu type __data;\ 3764257Sgblack@eecs.umich.edu 3774259Sgblack@eecs.umich.edu//This closes off the class and union started by the above macro. It is 3784259Sgblack@eecs.umich.edu//followed by a typedef which makes "name" refer to a BitfieldOperator 3794259Sgblack@eecs.umich.edu//class inheriting from the class and union just defined, which completes 3804259Sgblack@eecs.umich.edu//building up the type for the user. 3814257Sgblack@eecs.umich.edu#define EndBitUnion(name) \ 3824257Sgblack@eecs.umich.edu }; \ 3834257Sgblack@eecs.umich.edu }; \ 3844258Sgblack@eecs.umich.edu typedef BitfieldBackend::BitUnionOperators< \ 3854258Sgblack@eecs.umich.edu BitfieldUnderlyingClasses::name::__DataType, \ 3864258Sgblack@eecs.umich.edu BitfieldUnderlyingClasses::name> name; 3874257Sgblack@eecs.umich.edu 3884259Sgblack@eecs.umich.edu//This sets up a bitfield which has other bitfields nested inside of it. The 3894259Sgblack@eecs.umich.edu//__data member functions like the "underlying storage" of the top level 3904259Sgblack@eecs.umich.edu//BitUnion. Like everything else, it overlays with the top level storage, so 3914259Sgblack@eecs.umich.edu//making it a regular bitfield type makes the entire thing function as a 3924262Sgblack@eecs.umich.edu//regular bitfield when referred to by itself. 3934262Sgblack@eecs.umich.edu#define __SubBitUnion(fieldType, first, last, name) \ 3944262Sgblack@eecs.umich.edu class : public BitfieldBackend::BitfieldTypes<__DataType> \ 3954262Sgblack@eecs.umich.edu { \ 3964262Sgblack@eecs.umich.edu public: \ 3974257Sgblack@eecs.umich.edu union { \ 3984262Sgblack@eecs.umich.edu fieldType<first, last> __data; 3994257Sgblack@eecs.umich.edu 4004259Sgblack@eecs.umich.edu//This closes off the union created above and gives it a name. Unlike the top 4014259Sgblack@eecs.umich.edu//level BitUnion, we're interested in creating an object instead of a type. 4024262Sgblack@eecs.umich.edu//The operators are defined in the macro itself instead of a class for 4034262Sgblack@eecs.umich.edu//technical reasons. If someone determines a way to move them to one, please 4044262Sgblack@eecs.umich.edu//do so. 4054262Sgblack@eecs.umich.edu#define EndSubBitUnion(name) \ 4064262Sgblack@eecs.umich.edu }; \ 4074262Sgblack@eecs.umich.edu inline operator const __DataType () \ 4084262Sgblack@eecs.umich.edu { return __data; } \ 4094262Sgblack@eecs.umich.edu \ 4104262Sgblack@eecs.umich.edu inline const __DataType operator = (const __DataType & _data) \ 4114262Sgblack@eecs.umich.edu { __data = _data; } \ 4124262Sgblack@eecs.umich.edu } name; 4134258Sgblack@eecs.umich.edu 4144258Sgblack@eecs.umich.edu//Regular bitfields 4154262Sgblack@eecs.umich.edu//These define macros for read/write regular bitfield based subbitfields. 4164258Sgblack@eecs.umich.edu#define SubBitUnion(name, first, last) \ 4174262Sgblack@eecs.umich.edu __SubBitUnion(Bitfield, first, last, name) 4184257Sgblack@eecs.umich.edu 4194274Sgblack@eecs.umich.edu//Regular bitfields 4204274Sgblack@eecs.umich.edu//These define macros for read/write regular bitfield based subbitfields. 4214274Sgblack@eecs.umich.edu#define SignedSubBitUnion(name, first, last) \ 4224274Sgblack@eecs.umich.edu __SubBitUnion(SignedBitfield, first, last, name) 4234274Sgblack@eecs.umich.edu 4244259Sgblack@eecs.umich.edu//Use this to define an arbitrary type overlayed with bitfields. 4254257Sgblack@eecs.umich.edu#define BitUnion(type, name) __BitUnion(type, name) 4264257Sgblack@eecs.umich.edu 4274259Sgblack@eecs.umich.edu//Use this to define conveniently sized values overlayed with bitfields. 4284257Sgblack@eecs.umich.edu#define BitUnion64(name) __BitUnion(uint64_t, name) 4294257Sgblack@eecs.umich.edu#define BitUnion32(name) __BitUnion(uint32_t, name) 4304257Sgblack@eecs.umich.edu#define BitUnion16(name) __BitUnion(uint16_t, name) 4314257Sgblack@eecs.umich.edu#define BitUnion8(name) __BitUnion(uint8_t, name) 4324103Ssaidi@eecs.umich.edu 4331112SN/A#endif // __BASE_BITFIELD_HH__ 434