ModuleWare Reference Guide - Hornad

IntroductionVHDL Coding StyleNotes• The default value for the parameter mode is Logical.VHDL Coding StyleAll parts support the nine-value multi-valued logic style (MVL9) which is used by the IEEEstd_ulogic and std_logic types. MVL9 supports the nine values (0, 1, L, H, X, -, U, W and Z).Many parts can use the alternative four-value (MVL4) style which is used by one particularsubtype of std_ulogic and supports the four values (0, 1, X and Z) only. The MVL4 style can beset as a preference in the Style tab of the VHDL Options dialog box as described in the “SettingPreferences” section of the HDL Designer Series User Manual.The following parts support the alternative VHDL coding styles:accaddsubadffalu181clkdivcntrdffdlatchfifoincdecjkffjklatchlatchlshiftmodcntrmux2mux4mux8ram2pramregfilersffrshiftrslatchshiftpsshiftspstacktfftlatchtribuftribustrifftriinvvarshiftSignals and VariablesMany of the ModuleWare parts use an internal variable in the generated VHDL. For example,the Multiplier (mult) normally uses the internal variables dtemp, temp0 and temp1 in the defaultgenerated code:I0combo : PROCESS (din0, din1)VARIABLE dtemp : unsigned(1 DOWNTO 0);VARIABLE temp0 : unsigned(0 DOWNTO 0);VARIABLE temp1 : unsigned(0 DOWNTO 0);BEGINtemp0(0) := din0;temp1(0) := din1;dtemp := (temp0 * temp1);prod