src/arch/generic/vec_pred_reg.hh - public/gem5 - Git at Google

 // Copyright (c) 2017 ARM Limited
 // All rights reserved
 //
 // The license below extends only to copyright in the software and shall
 // not be construed as granting a license to any other intellectual
 // property including but not limited to intellectual property relating
 // to a hardware implementation of the functionality of the software
 // licensed hereunder.  You may use the software subject to the license
 // terms below provided that you ensure that this notice is replicated
 // unmodified and in its entirety in all distributions of the software,
 // modified or unmodified, in source code or in binary form.
 //
 // 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.
 //
 // Authors: Giacomo Gabrielli
 //          Rekai Gonzalez
 //          Javier Setoain

 #ifndef __ARCH_GENERIC_VEC_PRED_REG_HH__
 #define __ARCH_GENERIC_VEC_PRED_REG_HH__

 #include <array>
 #include <cassert>
 #include <vector>

 #include "arch/generic/vec_reg.hh"
 #include "base/cprintf.hh"

 template <size_t NumBits, bool Packed>
 class VecPredRegContainer;

 /// Predicate register view.
 ///
 /// This generic class implements the View in an MVC pattern, similarly to
 /// @see VecRegT. Since predicates are mainly used in conjunction with vectors
 /// to specify which lanes are active in a vector operation, the class is
 /// templated on the vector element type to simplify ISA definitions.
 /// @tparam VecElem Type of the vector elements.
 /// @tparam NumElems Number of vector elements making up the view.
 /// @tparam Packed True if the predicate register relies on a packed
 /// representation, i.e. adjacent bits refer to different vector elements
 /// irrespective of the vector element size (e.g. this is the case for
 /// AVX-512). If false, the predicate register relies on an unpacked
 /// representation, where each bit refers to the corresponding byte in a vector
 /// register (e.g. this is the case for ARM SVE).
 /// @tparam Const True if the underlying container can be modified through
 /// the view.
 template <typename VecElem, size_t NumElems, bool Packed, bool Const>
 class VecPredRegT
 {
   protected:
     /// Size of the register in bits.
     static constexpr size_t NUM_BITS = Packed ? NumElems :
                                                 sizeof(VecElem) * NumElems;

   public:
     /// Container type alias.
     using Container = typename std::conditional<
         Const,
         const VecPredRegContainer<NUM_BITS, Packed>,
         VecPredRegContainer<NUM_BITS, Packed>>::type;

   protected:
     // Alias for this type
     using MyClass = VecPredRegT<VecElem, NumElems, Packed, Const>;
     /// Container corresponding to this view.
     Container& container;

   public:
     VecPredRegT(Container& c) : container(c) {}

     /// Reset the register to an all-false value.
     template<bool Condition = !Const>
     typename std::enable_if<Condition, void>::type
     reset() { container.reset(); }

     /// Reset the register to an all-true value.
     template<bool Condition = !Const>
     typename std::enable_if<Condition, void>::type
     set() { container.set(); }

     template<bool Condition = !Const>
     typename std::enable_if<Condition, MyClass&>::type
     operator=(const MyClass& that)
     {
         container = that.container;
         return *this;
     }

     const bool&
     operator[](size_t idx) const
     {
         return container[idx * (Packed ? 1 : sizeof(VecElem))];
     }

     template<bool Condition = !Const>
     typename std::enable_if<Condition, bool&>::type
     operator[](size_t idx)
     {
         return container[idx * (Packed ? 1 : sizeof(VecElem))];
     }

     /// Return an element of the predicate register as it appears
     /// in the raw (untyped) internal representation
     uint8_t
     get_raw(size_t idx) const
     {
         return container.get_bits(idx * (Packed ? 1 : sizeof(VecElem)),
                 (Packed ? 1 : sizeof(VecElem)));
     }

     /// Write a raw value in an element of the predicate register
     template<bool Condition = !Const>
     typename std::enable_if<Condition, void>::type
     set_raw(size_t idx, uint8_t val)
     {
         container.set_bits(idx * (Packed ? 1 : sizeof(VecElem)),
                 (Packed ? 1 : sizeof(VecElem)), val);
     }

     /// Equality operator, required to compare thread contexts.
     template<typename VE2, size_t NE2, bool P2, bool C2>
     bool
     operator==(const VecPredRegT<VE2, NE2, P2, C2>& that) const
     {
         return container == that.container;
     }

     /// Inequality operator, required to compare thread contexts.
     template<typename VE2, size_t NE2, bool P2, bool C2>
     bool
     operator!=(const VecPredRegT<VE2, NE2, P2, C2>& that) const
     {
         return !operator==(that);
     }

     friend std::ostream&
     operator<<(std::ostream& os, const MyClass& p)
     {
         // 0-sized is not allowed
         os << '[' << p.container[0];
         for (int i = 0; i < p.NUM_BITS; ++i) {
             os << " " << (p.container[i] ? 1 : 0);
         }
         os << ']';
         return os;
     }

     /// Returns a string representation of the register content.
     const std::string print() const { return csprintf("%s", *this); }

     /// Returns true if the first active element of the register is true.
     /// @param mask Input mask used to filter the predicates to be tested.
     /// @param actual_num_elems Actual number of vector elements considered for
     /// the test (corresponding to the current vector length).
     template <bool MC>
     bool
     firstActive(const VecPredRegT<VecElem, NumElems, Packed, MC>& mask,
                 size_t actual_num_elems) const
     {
         assert(actual_num_elems <= NumElems);
         for (int i = 0; i < actual_num_elems; ++i) {
             if (mask[i]) {
                 return (*this)[i];
             }
         }
         return false;
     }

     /// Returns true if there are no active elements in the register.
     /// @param mask Input mask used to filter the predicates to be tested.
     /// @param actual_num_elems Actual number of vector elements considered for
     /// the test (corresponding to the current vector length).
     template <bool MC>
     bool
     noneActive(const VecPredRegT<VecElem, NumElems, Packed, MC>& mask,
                size_t actual_num_elems) const
     {
         assert(actual_num_elems <= NumElems);
         for (int i = 0; i < actual_num_elems; ++i) {
             if (mask[i] && operator[](i)) {
                 return false;
             }
         }
         return true;
     }

     /// Returns true if the last active element of the register is true.
     /// @param mask Input mask used to filter the predicates to be tested.
     /// @param actual_num_elems Actual number of vector elements considered for
     /// the test (corresponding to the current vector length).
     template <bool MC>
     bool
     lastActive(const VecPredRegT<VecElem, NumElems, Packed, MC>& mask,
                size_t actual_num_elems) const
     {
         assert(actual_num_elems <= NumElems);
         for (int i = actual_num_elems - 1; i >= 0; --i) {
             if (mask[i]) {
                 return operator[](i);
             }
         }
         return false;
     }
 };

 /// Generic predicate register container.
 ///
 /// This generic class implements the Model in an MVC pattern, similarly to
 /// @see VecRegContainer.
 /// @tparam NumBits Size of the container in bits.
 /// @tparam Packed See @VecRegT.
 template <size_t NumBits, bool Packed>
 class VecPredRegContainer
 {
     static_assert(NumBits > 0,
                   "Size of a predicate register must be > 0");

   public:
     static constexpr size_t NUM_BITS = NumBits;
     using Container = std::array<bool, NumBits>;

   private:
     Container container;
     // Alias for this type
     using MyClass = VecPredRegContainer<NumBits, Packed>;

   public:
     VecPredRegContainer() {}
     VecPredRegContainer(const VecPredRegContainer &) = default;

     MyClass&
     operator=(const MyClass& that)
     {
         if (&that == this)
             return *this;
         container = that.container;
         return *this;
     }

     /// Required for de-serialization.
     MyClass&
     operator=(const std::vector<uint8_t>& that)
     {
         assert(that.size() == NUM_BITS);
         std::copy(that.begin(), that.end(), container.begin());
         return *this;
     }

     /// Resets the predicate register to an all-false register.
     void
     reset()
     {
         container.fill(false);
     }

     /// Sets the predicate register to an all-true value.
     void
     set()
     {
         container.fill(true);
     }

     /// Equality operator, required to compare thread contexts.
     template<size_t N2, bool P2>
     inline bool
     operator==(const VecPredRegContainer<N2, P2>& that) const
     {
         return NumBits == N2 && Packed == P2 && container == that.container;
     }

     /// Inequality operator, required to compare thread contexts.
     template<size_t N2, bool P2>
     bool
     operator!=(const VecPredRegContainer<N2, P2>& that) const
     {
         return !operator==(that);
     }

     /// Returns a reference to a specific element of the internal container.
     bool& operator[](size_t idx) { return container[idx]; }

     /// Returns a const reference to a specific element of the internal
     /// container.
     const bool& operator[](size_t idx) const { return container[idx]; }

     /// Returns a subset of bits starting from a specific element in the
     /// container.
     uint8_t
     get_bits(size_t idx, uint8_t nbits) const
     {
         assert(nbits > 0 && nbits <= 8 && (idx + nbits - 1) < NumBits);
         uint8_t v = 0;
         idx = idx + nbits - 1;
         for (int i = 0; i < nbits; ++i, --idx) {
             v <<= 1;
             v |= container[idx];
         }
         return v;
     }

     /// Set a subset of bits starting from a specific element in the
     /// container.
     void
     set_bits(size_t idx, uint8_t nbits, uint8_t bval)
     {
         assert(nbits > 0 && nbits <= 8 && (idx + nbits - 1) < NumBits);
         for (int i = 0; i < nbits; ++i, ++idx) {
             container[idx] = bval & 1;
             bval >>= 1;
         }
     }

     /// Returns a string representation of the register content.
     const std::string print() const { return csprintf("%s", *this); }

     friend std::ostream&
     operator<<(std::ostream& os, const MyClass& v)
     {
         for (auto b: v.container) {
             os << csprintf("%d", b);
         }
         return os;
     }

     /// Create a view of this container.
     ///
     /// If NumElems is provided, the size of the container is bounds-checked,
     /// otherwise the size is inferred from the container size.
     /// @tparam VecElem Type of the vector elements.
     /// @tparam NumElems Number of vector elements making up the view.
     /// @{
     template <typename VecElem,
               size_t NumElems = (Packed ? NumBits : NumBits / sizeof(VecElem))>
     VecPredRegT<VecElem, NumElems, Packed, true> as() const
     {
         static_assert((Packed && NumElems <= NumBits) ||
                       (!Packed &&
                        NumBits % sizeof(VecElem) == 0 &&
                        sizeof(VecElem) * NumElems <= NumBits),
                       "Container size incompatible with view size");
         return VecPredRegT<VecElem, NumElems, Packed, true>(*this);
     }

     template <typename VecElem,
               size_t NumElems = (Packed ? NumBits : NumBits / sizeof(VecElem))>
     VecPredRegT<VecElem, NumElems, Packed, false> as()
     {
         static_assert((Packed && NumElems <= NumBits) ||
                       (!Packed &&
                        NumBits % sizeof(VecElem) == 0 &&
                        sizeof(VecElem) * NumElems <= NumBits),
                       "Container size incompatible with view size");
         return VecPredRegT<VecElem, NumElems, Packed, false>(*this);
     }
     /// @}
 };

 /// Helper functions used for serialization/de-serialization
 template <size_t NumBits, bool Packed>
 inline bool
 to_number(const std::string& value, VecPredRegContainer<NumBits, Packed>& p)
 {
     int i = 0;
     for (const auto& c: value) {
         p[i] = (c == '1');
     }
     return true;
 }

 /// Dummy type aliases and constants for architectures that do not implement
 /// vector predicate registers.
 /// @{
 constexpr bool DummyVecPredRegHasPackedRepr = false;
 using DummyVecPredReg = VecPredRegT<DummyVecElem, DummyNumVecElemPerVecReg,
                                     DummyVecPredRegHasPackedRepr, false>;
 using DummyConstVecPredReg = VecPredRegT<DummyVecElem,
                                          DummyNumVecElemPerVecReg,
                                          DummyVecPredRegHasPackedRepr, true>;
 using DummyVecPredRegContainer = DummyVecPredReg::Container;
 constexpr size_t DummyVecPredRegSizeBits = 8;
 /// @}

 #endif  // __ARCH_GENERIC_VEC_PRED_REG_HH__
	// Copyright (c) 2017 ARM Limited
	// All rights reserved
	//
	// The license below extends only to copyright in the software and shall
	// not be construed as granting a license to any other intellectual
	// property including but not limited to intellectual property relating
	// to a hardware implementation of the functionality of the software
	// licensed hereunder. You may use the software subject to the license
	// terms below provided that you ensure that this notice is replicated
	// unmodified and in its entirety in all distributions of the software,
	// modified or unmodified, in source code or in binary form.
	//
	// 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.
	//
	// Authors: Giacomo Gabrielli
	// Rekai Gonzalez
	// Javier Setoain

	#ifndef __ARCH_GENERIC_VEC_PRED_REG_HH__
	#define __ARCH_GENERIC_VEC_PRED_REG_HH__

	#include <array>
	#include <cassert>
	#include <vector>

	#include "arch/generic/vec_reg.hh"
	#include "base/cprintf.hh"

	template <size_t NumBits, bool Packed>
	class VecPredRegContainer;

	/// Predicate register view.
	///
	/// This generic class implements the View in an MVC pattern, similarly to
	/// @see VecRegT. Since predicates are mainly used in conjunction with vectors
	/// to specify which lanes are active in a vector operation, the class is
	/// templated on the vector element type to simplify ISA definitions.
	/// @tparam VecElem Type of the vector elements.
	/// @tparam NumElems Number of vector elements making up the view.
	/// @tparam Packed True if the predicate register relies on a packed
	/// representation, i.e. adjacent bits refer to different vector elements
	/// irrespective of the vector element size (e.g. this is the case for
	/// AVX-512). If false, the predicate register relies on an unpacked
	/// representation, where each bit refers to the corresponding byte in a vector
	/// register (e.g. this is the case for ARM SVE).
	/// @tparam Const True if the underlying container can be modified through
	/// the view.
	template <typename VecElem, size_t NumElems, bool Packed, bool Const>
	class VecPredRegT
	{
	protected:
	/// Size of the register in bits.
	static constexpr size_t NUM_BITS = Packed ? NumElems :
	sizeof(VecElem) * NumElems;

	public:
	/// Container type alias.
	using Container = typename std::conditional<
	Const,
	const VecPredRegContainer<NUM_BITS, Packed>,
	VecPredRegContainer<NUM_BITS, Packed>>::type;

	protected:
	// Alias for this type
	using MyClass = VecPredRegT<VecElem, NumElems, Packed, Const>;
	/// Container corresponding to this view.
	Container& container;

	public:
	VecPredRegT(Container& c) : container(c) {}

	/// Reset the register to an all-false value.
	template<bool Condition = !Const>
	typename std::enable_if<Condition, void>::type
	reset() { container.reset(); }

	/// Reset the register to an all-true value.
	template<bool Condition = !Const>
	typename std::enable_if<Condition, void>::type
	set() { container.set(); }

	template<bool Condition = !Const>
	typename std::enable_if<Condition, MyClass&>::type
	operator=(const MyClass& that)
	{
	container = that.container;
	return *this;
	}

	const bool&
	operator[](size_t idx) const
	{
	return container[idx * (Packed ? 1 : sizeof(VecElem))];
	}

	template<bool Condition = !Const>
	typename std::enable_if<Condition, bool&>::type
	operator[](size_t idx)
	{
	return container[idx * (Packed ? 1 : sizeof(VecElem))];
	}

	/// Return an element of the predicate register as it appears
	/// in the raw (untyped) internal representation
	uint8_t
	get_raw(size_t idx) const
	{
	return container.get_bits(idx * (Packed ? 1 : sizeof(VecElem)),
	(Packed ? 1 : sizeof(VecElem)));
	}

	/// Write a raw value in an element of the predicate register
	template<bool Condition = !Const>
	typename std::enable_if<Condition, void>::type
	set_raw(size_t idx, uint8_t val)
	{
	container.set_bits(idx * (Packed ? 1 : sizeof(VecElem)),
	(Packed ? 1 : sizeof(VecElem)), val);
	}

	/// Equality operator, required to compare thread contexts.
	template<typename VE2, size_t NE2, bool P2, bool C2>
	bool
	operator==(const VecPredRegT<VE2, NE2, P2, C2>& that) const
	{
	return container == that.container;
	}

	/// Inequality operator, required to compare thread contexts.
	template<typename VE2, size_t NE2, bool P2, bool C2>
	bool
	operator!=(const VecPredRegT<VE2, NE2, P2, C2>& that) const
	{
	return !operator==(that);
	}

	friend std::ostream&
	operator<<(std::ostream& os, const MyClass& p)
	{
	// 0-sized is not allowed
	os << '[' << p.container[0];
	for (int i = 0; i < p.NUM_BITS; ++i) {
	os << " " << (p.container[i] ? 1 : 0);
	}
	os << ']';
	return os;
	}

	/// Returns a string representation of the register content.
	const std::string print() const { return csprintf("%s", *this); }

	/// Returns true if the first active element of the register is true.
	/// @param mask Input mask used to filter the predicates to be tested.
	/// @param actual_num_elems Actual number of vector elements considered for
	/// the test (corresponding to the current vector length).
	template <bool MC>
	bool
	firstActive(const VecPredRegT<VecElem, NumElems, Packed, MC>& mask,
	size_t actual_num_elems) const
	{
	assert(actual_num_elems <= NumElems);
	for (int i = 0; i < actual_num_elems; ++i) {
	if (mask[i]) {
	return (*this)[i];
	}
	}
	return false;
	}

	/// Returns true if there are no active elements in the register.
	/// @param mask Input mask used to filter the predicates to be tested.
	/// @param actual_num_elems Actual number of vector elements considered for
	/// the test (corresponding to the current vector length).
	template <bool MC>
	bool
	noneActive(const VecPredRegT<VecElem, NumElems, Packed, MC>& mask,
	size_t actual_num_elems) const
	{
	assert(actual_num_elems <= NumElems);
	for (int i = 0; i < actual_num_elems; ++i) {
	if (mask[i] && operator[](i)) {
	return false;
	}
	}
	return true;
	}

	/// Returns true if the last active element of the register is true.
	/// @param mask Input mask used to filter the predicates to be tested.
	/// @param actual_num_elems Actual number of vector elements considered for
	/// the test (corresponding to the current vector length).
	template <bool MC>
	bool
	lastActive(const VecPredRegT<VecElem, NumElems, Packed, MC>& mask,
	size_t actual_num_elems) const
	{
	assert(actual_num_elems <= NumElems);
	for (int i = actual_num_elems - 1; i >= 0; --i) {
	if (mask[i]) {
	return operator[](i);
	}
	}
	return false;
	}
	};

	/// Generic predicate register container.
	///
	/// This generic class implements the Model in an MVC pattern, similarly to
	/// @see VecRegContainer.
	/// @tparam NumBits Size of the container in bits.
	/// @tparam Packed See @VecRegT.
	template <size_t NumBits, bool Packed>
	class VecPredRegContainer
	{
	static_assert(NumBits > 0,
	"Size of a predicate register must be > 0");

	public:
	static constexpr size_t NUM_BITS = NumBits;
	using Container = std::array<bool, NumBits>;

	private:
	Container container;
	// Alias for this type
	using MyClass = VecPredRegContainer<NumBits, Packed>;

	public:
	VecPredRegContainer() {}
	VecPredRegContainer(const VecPredRegContainer &) = default;

	MyClass&
	operator=(const MyClass& that)
	{
	if (&that == this)
	return *this;
	container = that.container;
	return *this;
	}

	/// Required for de-serialization.
	MyClass&
	operator=(const std::vector<uint8_t>& that)
	{
	assert(that.size() == NUM_BITS);
	std::copy(that.begin(), that.end(), container.begin());
	return *this;
	}

	/// Resets the predicate register to an all-false register.
	void
	reset()
	{
	container.fill(false);
	}

	/// Sets the predicate register to an all-true value.
	void
	set()
	{
	container.fill(true);
	}

	/// Equality operator, required to compare thread contexts.
	template<size_t N2, bool P2>
	inline bool
	operator==(const VecPredRegContainer<N2, P2>& that) const
	{
	return NumBits == N2 && Packed == P2 && container == that.container;
	}

	/// Inequality operator, required to compare thread contexts.
	template<size_t N2, bool P2>
	bool
	operator!=(const VecPredRegContainer<N2, P2>& that) const
	{
	return !operator==(that);
	}

	/// Returns a reference to a specific element of the internal container.
	bool& operator[](size_t idx) { return container[idx]; }

	/// Returns a const reference to a specific element of the internal
	/// container.
	const bool& operator[](size_t idx) const { return container[idx]; }

	/// Returns a subset of bits starting from a specific element in the
	/// container.
	uint8_t
	get_bits(size_t idx, uint8_t nbits) const
	{
	assert(nbits > 0 && nbits <= 8 && (idx + nbits - 1) < NumBits);
	uint8_t v = 0;
	idx = idx + nbits - 1;
	for (int i = 0; i < nbits; ++i, --idx) {
	v <<= 1;
	v \|= container[idx];
	}
	return v;
	}

	/// Set a subset of bits starting from a specific element in the
	/// container.
	void
	set_bits(size_t idx, uint8_t nbits, uint8_t bval)
	{
	assert(nbits > 0 && nbits <= 8 && (idx + nbits - 1) < NumBits);
	for (int i = 0; i < nbits; ++i, ++idx) {
	container[idx] = bval & 1;
	bval >>= 1;
	}
	}

	/// Returns a string representation of the register content.
	const std::string print() const { return csprintf("%s", *this); }

	friend std::ostream&
	operator<<(std::ostream& os, const MyClass& v)
	{
	for (auto b: v.container) {
	os << csprintf("%d", b);
	}
	return os;
	}

	/// Create a view of this container.
	///
	/// If NumElems is provided, the size of the container is bounds-checked,
	/// otherwise the size is inferred from the container size.
	/// @tparam VecElem Type of the vector elements.
	/// @tparam NumElems Number of vector elements making up the view.
	/// @{
	template <typename VecElem,
	size_t NumElems = (Packed ? NumBits : NumBits / sizeof(VecElem))>
	VecPredRegT<VecElem, NumElems, Packed, true> as() const
	{
	static_assert((Packed && NumElems <= NumBits) \|\|
	(!Packed &&
	NumBits % sizeof(VecElem) == 0 &&
	sizeof(VecElem) * NumElems <= NumBits),
	"Container size incompatible with view size");
	return VecPredRegT<VecElem, NumElems, Packed, true>(*this);
	}

	template <typename VecElem,
	size_t NumElems = (Packed ? NumBits : NumBits / sizeof(VecElem))>
	VecPredRegT<VecElem, NumElems, Packed, false> as()
	{
	static_assert((Packed && NumElems <= NumBits) \|\|
	(!Packed &&
	NumBits % sizeof(VecElem) == 0 &&
	sizeof(VecElem) * NumElems <= NumBits),
	"Container size incompatible with view size");
	return VecPredRegT<VecElem, NumElems, Packed, false>(*this);
	}
	/// @}
	};

	/// Helper functions used for serialization/de-serialization
	template <size_t NumBits, bool Packed>
	inline bool
	to_number(const std::string& value, VecPredRegContainer<NumBits, Packed>& p)
	{
	int i = 0;
	for (const auto& c: value) {
	p[i] = (c == '1');
	}
	return true;
	}

	/// Dummy type aliases and constants for architectures that do not implement
	/// vector predicate registers.
	/// @{
	constexpr bool DummyVecPredRegHasPackedRepr = false;
	using DummyVecPredReg = VecPredRegT<DummyVecElem, DummyNumVecElemPerVecReg,
	DummyVecPredRegHasPackedRepr, false>;
	using DummyConstVecPredReg = VecPredRegT<DummyVecElem,
	DummyNumVecElemPerVecReg,
	DummyVecPredRegHasPackedRepr, true>;
	using DummyVecPredRegContainer = DummyVecPredReg::Container;
	constexpr size_t DummyVecPredRegSizeBits = 8;
	/// @}

	#endif // __ARCH_GENERIC_VEC_PRED_REG_HH__