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fb3be420b4
SystemVerilog 2023 adds soft packed unions. They are pretty much the same
as regular packed unions except they remove the restriction that all
elements have to have the same packed width.
The packed with of the union itself is the maximum packed width of any
element.
The bits of each member are right-justified towards the LSBs and this
representation is applied recursively to nested soft packed unions. The
existing packed union member offsets already use that layout. When
accessing a field that is smaller than the union itself upper bits are
ignored for both reading and writing.
The `soft` qualifier implies a packed union so both `union soft U { ... }`
and `union soft packed U { ... }` declare a soft packed union.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
97 lines
3.3 KiB
C++
97 lines
3.3 KiB
C++
#ifndef IVL_netstruct_H
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#define IVL_netstruct_H
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/*
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* Copyright (c) 2011-2026 Stephen Williams (steve@icarus.com)
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*
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* This source code is free software; you can redistribute it
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* and/or modify it in source code form under the terms of the GNU
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* General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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# include "LineInfo.h"
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# include <vector>
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# include "ivl_target.h"
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# include "nettypes.h"
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class Design;
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class netstruct_t : public LineInfo, public ivl_type_s {
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public:
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struct member_t {
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perm_string name;
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ivl_type_t net_type;
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inline ivl_variable_type_t data_type() const
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{ return net_type->base_type(); };
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bool get_signed() const
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{ return net_type->get_signed(); }
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};
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public:
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netstruct_t() = default;
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~netstruct_t() override;
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// If this is a union (instead of struct) then this flag is
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// set. We handle union and struct together because they are
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// so similar.
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void union_flag(bool, bool soft = false);
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bool union_flag(void) const;
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bool soft_union(void) const;
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void packed(bool flag);
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bool packed(void) const override;
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// When the struct is accessed as a primary it can be signed or unsigned
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void set_signed(bool flag) { signed_ = flag; }
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bool get_signed(void) const override { return signed_; }
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// Append a new member to the struct/union. This must be done
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// after the union_flag and packed settings are set. This
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// function does error checking, and the "des" argument is
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// only present so that it can set error flags.
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void append_member(Design*des, const member_t&);
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// Given the name of a member, return a pointer to the member
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// description, and set the off value to be the offset into
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// the packed value where the member begins.
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const struct member_t* packed_member(perm_string name, unsigned long&off) const;
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const std::vector<member_t>& members() const { return members_; }
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// Return the width (in bits) of the packed record, or -1 if
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// the record is not packed.
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long packed_width() const override;
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netranges_t slice_dimensions() const override;
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// Return the base type of the packed record, or
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// IVL_VT_NO_TYPE if the record is not packed.
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ivl_variable_type_t base_type() const override;
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private:
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bool test_compatibility(ivl_type_t that) const override;
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bool test_equivalence(ivl_type_t that) const override;
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private:
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bool union_ = false;
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bool soft_union_ = false;
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bool packed_ = false;
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bool signed_ = false;
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std::vector<member_t>members_;
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};
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inline bool netstruct_t::union_flag(void) const { return union_; }
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inline bool netstruct_t::soft_union(void) const { return soft_union_; }
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inline bool netstruct_t::packed(void) const { return packed_; }
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#endif /* IVL_netstruct_H */
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