// Copyright 2014 Citra Emulator Project
// Licensed under GPLv2
// Refer to the license.txt file included.
#pragma once
// Copyright 2014 Tony Wasserka
// 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 owner 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,
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// 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.
/*
* Standardized way to define a group of registers and corresponding data structures. To define
* a new register set, first define struct containing an enumeration called "Id" containing
* all register IDs and a template union called "Struct". Specialize the Struct union for any
* register ID which needs to be accessed in a specialized way. You can then declare the object
* containing all register values using the RegisterSet<BaseType, DefiningStruct> type, where
* BaseType is the underlying type of each register (e.g. u32).
* Of course, you'll usually want to implement the Struct template such that they are of the same
* size as BaseType. However, it's also possible to make it larger, e.g. when you want to describe
* multiple registers with the same structure.
*
* Example:
*
* struct Regs {
* enum Id : u32 {
* Value1 = 0,
* Value2 = 1,
* Value3 = 2,
* NumIds = 3
* };
*
* // declare register definition structures
* template<Id id>
* union Struct;
* };
*
* // Define register set object
* RegisterSet<u32, CommandIds> registers;
*
* // define register definition structures
* template<>
* union Regs::Struct<Regs::Value1> {
* BitField<0, 4, u32> some_field;
* BitField<4, 3, u32> some_other_field;
* };
*
* Usage in external code (within SomeNamespace scope):
*
* For a register which maps to a single index:
* registers.Get<Regs::Value1>().some_field = some_value;
*
* For a register which maps to different indices, e.g. a group of similar registers
* registers.Get<Regs::Value1>(index).some_field = some_value;
*
*
* @tparam BaseType Base type used for storing individual registers, e.g. u32
* @tparam RegDefinition Class defining an enumeration called "Id" and a template<Id id> union, as described above.
* @note RegDefinition::Id needs to have an enum value called NumIds defining the number of registers to be allocated.
*/
template<typename BaseType, typename RegDefinition>
struct RegisterSet {
// Register IDs
using Id = typename RegDefinition::Id;
// type used for *this
using ThisType = RegisterSet<BaseType, RegDefinition>;
// Register definition structs, defined in RegDefinition
template<Id id>
using Struct = typename RegDefinition::template Struct<id>;
/*
* Lookup register with the given id and return it as the corresponding structure type.
* @note This just forwards the arguments to Get(Id).
*/
template<Id id>
const Struct<id>& Get() const {
return Get<id>(id);
}
/*
* Lookup register with the given id and return it as the corresponding structure type.
* @note This just forwards the arguments to Get(Id).
*/
template<Id id>
Struct<id>& Get() {
return Get<id>(id);
}
/*
* Lookup register with the given index and return it as the corresponding structure type.
* @todo Is this portable with regards to structures larger than BaseType?
* @note if index==id, you don't need to specify the function parameter.
*/
template<Id id>
const Struct<id>& Get(const Id& index) const {
const int idx = static_cast<size_t>(index);
return *reinterpret_cast<const Struct<id>*>(&raw[idx]);
}
/*
* Lookup register with the given index and return it as the corresponding structure type.
* @note This just forwards the arguments to the const version of Get(Id).
* @note if index==id, you don't need to specify the function parameter.
*/
template<Id id>
Struct<id>& Get(const Id& index) {
return const_cast<Struct<id>&>(GetThis().Get<id>(index));
}
/*
* Plain array access.
* @note If you want to have this casted to a register defininition struct, use Get() instead.
*/
const BaseType& operator[] (const Id& id) const {
return raw[static_cast<size_t>(id)];
}
/*
* Plain array access.
* @note If you want to have this casted to a register defininition struct, use Get() instead.
* @note This operator just forwards its argument to the const version.
*/
BaseType& operator[] (const Id& id) {
return const_cast<BaseType&>(GetThis()[id]);
}
private:
/*
* Returns a const reference to "this".
*/
const ThisType& GetThis() const {
return static_cast<const ThisType&>(*this);
}
BaseType raw[Id::NumIds];
};
