ModuleWare Reference Guide - Hornad

Bit Tally (tally)Arithmetic PartsBit Tally (tally)This part counts the number of bits of input data on bus port dinmatching the scalar input port ibit. The result is placed in the outputdata port dout.If the width of the output port dout is greater than the width required tostore the result, 0 is padded in the result. If the width of the output portis less than the width required to store the result, extra most significantbits from the result are ignored.This part is equivalent to (n-1) single-bit incrementers, where n is width of input port din. Notethat the hardware performance depends upon the width of the output port dout.Functiondout = N where N is the number of bits of din equal to ibitTruth TableAn 8-bit input, 3-bit output ExampleTable 6-18. Bit Tally Truth Tabledin ibit dout00100010 0 11001001111 0 01101110100 1 10010111011 1 110ParametersTable 6-19. Bit Tally ParametersParameter Values Defaultdin, dout Port widths (must be > 1) AutomaticDesign Rule Checks• An error is issued if the width of any port cannot be determined or if port ibit, does not havea fixed width of 1.• A warning is issued and HDL generation fails for this part if any of the ports are notconnected.ModuleWare Reference Manual, Library Version 1.9 113September 18, 2008