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Tidy up reduction functions in support.cc 

This removes some unnecessary code duplication as the functions
only differ (or need to differ) in two places.
This commit is contained in:
Nick Gasson 2008-09-13 18:20:12 +01:00
parent e5abe182c1
commit c5263268ed
2 changed files with 23 additions and 32 deletions
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53
tgt-vhdl/support.cc
View File

@ -84,6 +84,23 @@ void support_function::emit_ternary(std::ostream &of, int level) const
<< "if T then return X; else return Y; end if;";
}
void support_function::emit_reduction(std::ostream &of, int level,
const char *op, char unit) const
{
// Emit a VHDL function emulating a Verilog reduction operator
// Where op is the corresponding VHDL operator and unit is the
// right-unit of the operator
of << "(X : std_logic_vector) return std_logic is"
<< nl_string(indent(level))
<< "variable R : std_logic := '" << unit << "';" << nl_string(level)
<< "begin" << nl_string(indent(level))
<< "for I in X'Range loop" << nl_string(indent(indent(level)))
<< "R := X(I) " << op << " R;" << nl_string(indent(level))
<< "end loop;" << nl_string(indent(level))
<< "return R;";
}
void support_function::emit(std::ostream &of, int level) const
{
of << nl_string(level) << "function " << function_name(type_);
@ -119,44 +136,16 @@ void support_function::emit(std::ostream &of, int level) const
<< "return X(0);";
break;
case SF_REDUCE_OR:
of << "(X : std_logic_vector) return std_logic is" << nl_string(level)
<< "begin" << nl_string(indent(level))
<< "for I in X'Range loop" << nl_string(indent(indent(level)))
<< "if X(I) = '1' then" << nl_string(indent(indent(indent(level))))
<< "return '1';" << nl_string(indent(indent(level)))
<< "end if;" << nl_string(indent(level))
<< "end loop;" << nl_string(indent(level))
<< "return '0';";
emit_reduction(of, level, "or", '0');
break;
case SF_REDUCE_AND:
of << "(X : std_logic_vector) return std_logic is" << nl_string(level)
<< "begin" << nl_string(indent(level))
<< "for I in X'Range loop" << nl_string(indent(indent(level)))
<< "if X(I) = '0' then" << nl_string(indent(indent(indent(level))))
<< "return '0';" << nl_string(indent(indent(level)))
<< "end if;" << nl_string(indent(level))
<< "end loop;" << nl_string(indent(level))
<< "return '1';";
emit_reduction(of, level, "and", '1');
break;
case SF_REDUCE_XOR:
of << "(X : std_logic_vector) return std_logic is"
<< nl_string(indent(level))
<< "variable R : std_logic := '0';" << nl_string(level)
<< "begin" << nl_string(indent(level))
<< "for I in X'Range loop" << nl_string(indent(indent(level)))
<< "R := X(I) xor R;" << nl_string(indent(level))
<< "end loop;" << nl_string(indent(level))
<< "return R;";
emit_reduction(of, level, "xnor", '0');
break;
case SF_REDUCE_XNOR:
of << "(X : std_logic_vector) return std_logic is"
<< nl_string(indent(level))
<< "variable R : std_logic := '0';" << nl_string(level)
<< "begin" << nl_string(indent(level))
<< "for I in X'Range loop" << nl_string(indent(indent(level)))
<< "R := X(I) xnor R;" << nl_string(indent(level))
<< "end loop;" << nl_string(indent(level))
<< "return R;";
emit_reduction(of, level, "xnor", '0');
break;
case SF_TERNARY_LOGIC:
of << "(T : Boolean; X, Y : std_logic) return std_logic is";

2
tgt-vhdl/support.hh
View File

@ -50,6 +50,8 @@ public:
private:
void emit_ternary(std::ostream &of, int level) const;
void emit_reduction(std::ostream &of, int level, const char *op,
char unit) const;
support_function_t type_;
};