ModuleWare Reference Guide - Hornad

IntroductionSlice SupportOtherwise the two signals are type casted or converted to the sign_type before arithmeticoperation takes place. There is no VHDL ambiguity in the output type because the resultingtype is signed if both signals are signed or unsigned if both signals are unsigned.The std_logic_arith package supports the operators (+,-,*) between two signals where any onecan be signed or unsigned. Thus, if the type of the two signals is either signed or unsigned, thearithmetic operation takes place without any type casting ignoring the sign_type parameter.Otherwise the two signals are type casted or converted to the sign_type before arithmeticoperation takes place. If both of the input signals are unsigned, the resulting type will beunsigned or std_logic_vector. Otherwise the resulting type is signed or std_logic_vector. Toresolve the ambiguity, signed or std_logic_vector qualifiers are inserted in the code whenappropriate.Comparison OperationsThe numeric_std package supports comparison between two signed or two unsigned signals.Thus, if both of the signals to be compared are signed or both are unsigned, the comparisonoperation takes place without any type casting and ignoring the sign_type parameter. Otherwisethe two signals are type casted or converted to the sign_type before comparison takes place.The std_logic_arith package supports comparison between two signals where any one can besigned or unsigned. Thus, if the type of the two signals is either signed or unsigned, thecomparison operation takes place without any type casting and ignoring the sign_typeparameter. Otherwise the two signals are type casted or converted to the sign_type beforecomparison takes place.Slice SupportFor both VHDL and Verilog, ModuleWare supports connecting one-dimensional slices (of anystart/stop range) to any of its models ports as long as the slice width complies with the expectedinput data width of the part.Connecting two-dimensional slices to any of the ModuleWare ports is not currently supported.32ModuleWare Reference Manual, Library Version 1.9September 18, 2008