Next, the case_item expressions are evaluated and compared in the given order. The expressions are executed once it fulfills the case_expression to its case_item value. If the case_expression doesn’t meet any of the case_item values, the default option is chosen at last. It is one of the procedural statements in Verilog.
The case statement in Verilog is much similar to switch- case statement in C language. Verilog code for full adder – Using case statement
So the final code is: `timescale 1ns / 1ps module Remember that the left-hand side entities must always be a reg (register) since registers are data storing elements. Then comes the logical expression which will be assigned to the output registers S and Cout. Procedural statements inside this always block gets executed once there’s any change in event A, B OR Cin. What we do over here is select the sensitivity list first, the change in which your output depends in almost every case, the input ports comprise the sensitivity list. This is the most general way of coding in behavioral style. Verilog code for full adder – Using always statement There are three different ways we can proceed with Verilog coding for full adder: Procedural_statement consists of sequential block statements. Here the timing_control can be a delay control, wait for a certain time, or can be an event control, wait for an event to occur. The syntax for always statement is: always To implement this, we’ll be using always statement. Well, if you’d look at the output of full adder, you’ll notice that the output changes whenever the input variable changes there is no don’t care value in the input. One is an initial statement which is executed only once and the other is always statement which gets executed once the sensitivity list gets enabled. The behavioral style mainly has two prominent statements. These keywords are defined in Verilog IEEE 1134 standard. The end of a module is followed by endmodule keyword.Then comes the procedural statements these statements are the assignment statements and are used to express the logical formulae.The port list contains the input, output and inout variables.It shows the input and output ports to a block. Now module in Verilog is just like the function concept in C. A module, being the functional block, describes a particular block in the digital system. The first and foremost task in Verilog coding is the declaration of the module.The construct of Verilog behavioral modeling consists of three main parts:
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