Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-04
This article relates to a MACRO-type circuit for a "less than" decoder which can be used in many places for VLSI system designs. More particularly, a macro is described which provides circuits for a new function to do what was previously done with several functions. This MACRO is for a "less-than decoder", but it can also be used as a "less-than or equal", "greater-than", or "greater-than or equal" decoder. The basic logic circuits in terms of AND and OR gates for achieving 3 of the above 4 cases are shown in Figs. 1, 2 and 3. The essential idea is as follows. A 16-bit "less-than" decoder, as in Fig. 1, must have a 4-bit input address A1A2A3A4, as shown. If the given binary address is, say, 3 (decimal 4), then the decoder will place a binary 1 in all bit positions less than binary 3 (i.e., less than the fourth position).