Combinational Combinational Logic and Logic and

VerilogVerilog

XORs and XORs and XNORsXNORs

XOR

XOR gates

Cascading XOR gates

Parity Parity GenerationGeneration

74x280 9-bit odd/even parity 74x280 9-bit odd/even parity generatorgenerator

Verilog for 9-input parity checker

Structural Verilog for 74x280 parity checker

Parity generation and checking Parity generation and checking for a 8-bit-wide memoryfor a 8-bit-wide memory

Error-correcting Error-correcting circuit for a 7-bit circuit for a 7-bit Hamming CodeHamming Code

Exors for Exors for parityparity

see next slide

Error-correcting circuit for a 7-bit Error-correcting circuit for a 7-bit Hamming CodeHamming Code

Behavioral Verilog for Hamming error correction

This is the This is the same code same code as in last as in last slideslide

Tree and Tree and Iterative Iterative circuitscircuits

Fig.6.74. XORs in comparators

Big OR functions

Iterative combinational Circuits

Iterative Iterative ComparatorsComparators

Iterative comparator of equalityIterative comparator of equality

74x85 4-bit comparator74x85 4-bit comparator

Output of A Output of A greater than greater than BB

Output of A Output of A less than Bless than B

output of A output of A equal Bequal B

4-bit of A 4-bit of A and 4-bit of and 4-bit of BB

Input of A Input of A less than Bless than B

Input of A Input of A equal Bequal B

Input of A Input of A greater than greater than BB

12-bit comparator using 74x85

Iterative Iterative circuitcircuit

Verilog for 74x85Verilog for 74x85

Five versions of Verilog Five versions of Verilog comparatorcomparator

Verilog comparatorVerilog comparator

Verilog comparatorVerilog comparator

Verilog comparatorVerilog comparator

Verilog ComparatorVerilog Comparator

74x682 8-bit comparator74x682 8-bit comparator

EQ and Greater

74x682 8-bit comparator74x682 8-bit comparator

Arithmetic Conditions (predicates) derived from 74x682 outputs