104 lines
3.4 KiB
C++
104 lines
3.4 KiB
C++
/*
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* Support functions for VHDL output.
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*
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* Copyright (C) 2008 Nick Gasson (nick@nickg.me.uk)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) 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 along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "vhdl_target.h"
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#include "support.hh"
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#include <cassert>
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#include <iostream>
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void require_support_function(support_function_t f)
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{
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vhdl_scope *scope = get_active_entity()->get_arch()->get_scope();
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if (!scope->have_declared(support_function::function_name(f)))
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scope->add_decl(new support_function(f));
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}
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const char *support_function::function_name(support_function_t type)
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{
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switch (type) {
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case SF_UNSIGNED_TO_BOOLEAN:
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return "Unsigned_To_Boolean";
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case SF_SIGNED_TO_BOOLEAN:
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return "Signed_To_Boolean";
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case SF_BOOLEAN_TO_LOGIC:
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return "Boolean_To_Logic";
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case SF_REDUCE_OR:
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return "Reduce_OR";
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default:
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assert(false);
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}
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}
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vhdl_type *support_function::function_type(support_function_t type)
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{
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switch (type) {
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case SF_UNSIGNED_TO_BOOLEAN:
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case SF_SIGNED_TO_BOOLEAN:
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return vhdl_type::boolean();
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case SF_BOOLEAN_TO_LOGIC:
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case SF_REDUCE_OR:
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return vhdl_type::std_logic();
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default:
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assert(false);
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}
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}
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void support_function::emit(std::ostream &of, int level) const
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{
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of << "function " << function_name(type_);
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switch (type_) {
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case SF_UNSIGNED_TO_BOOLEAN:
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of << "(X : unsigned) return Boolean is" << nl_string(level)
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<< "begin" << nl_string(indent(level))
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<< "return X /= To_Unsigned(0, X'Length);" << nl_string(level);
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break;
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case SF_SIGNED_TO_BOOLEAN:
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of << "(X : signed) return Boolean is" << nl_string(level)
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<< "begin" << nl_string(indent(level))
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<< "return X /= To_Signed(0, X'Length);" << nl_string (level);
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break;
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case SF_BOOLEAN_TO_LOGIC:
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of << "(B : Boolean) return std_logic is" << nl_string(level)
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<< "begin" << nl_string(indent(level))
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<< "if B then" << nl_string(indent(indent(level)))
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<< "return '1'" << nl_string(indent(level))
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<< "else" << nl_string(indent(indent(level)))
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<< "return '0'" << nl_string(indent(level))
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<< "end if;" << nl_string(level);
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break;
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case SF_REDUCE_OR:
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of << "(X : std_logic_vector) return std_logic is" << nl_string(level)
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<< "begin" << nl_string(indent(level))
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<< "for I in X'Range loop" << nl_string(indent(indent(level)))
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<< "if X(I) = '1' then" << nl_string(indent(indent(indent(level))))
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<< "return '1';" << nl_string(indent(indent(level)))
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<< "end if;" << nl_string(indent(level))
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<< "end loop;" << nl_string(indent(level))
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<< "return '0';" << nl_string(level);
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break;
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default:
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assert(false);
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}
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of << "end function;" << nl_string(level);
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}
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