Some data types in Verilog, such as reg, are 4-state. This means that each bit can be one of 4 values: 0,1,x,z. This means that each bit can be one of 4 values: 0,1,x,z. With the "case equality" operator, === , x's are compared, and the result is 1.

Normal part selects in Verilog require constants. So attempting the above with something like dword[i+7:i] is not allowed. So if you want to select a particular byte using a variable select, you can use the indexed part select.

Jun 26, 2013 · This isn't quite correct. In Verilog, a vector (or any other) object is 'true' if it is non-zero, and it is known - in other words, it does not contain x/z metavalues. So, it's not 'tested for equality to 0'. @VL: try not to combine Verilog and SV questions - they're different languages. You wouldn't ask a C question in a C++ group, or vice-versa.

Nov 4, 2014 · "<=" in Verilog is called non-blocking assignment which brings a whole lot of difference than "=" which is called as blocking assignment because of scheduling events in any vendor based simulators. It is Recommended to use non-blocking assignment for sequential logic and blocking assignment for combinational logic, only then it infers correct ...

Feb 16, 2016 · <= is a nonblocking assignment. It is used to describe sequential logic, like in your code example. Refer to IEEE Std 1800-2012, section 10.4.2 "Nonblocking procedural assignments".

Jul 17, 2013 · i have a verilog code in which there is a line as follows: parameter ADDR_WIDTH = 8 ; parameter RAM_DEPTH = 1 << ADDR_WIDTH; here what will be stored in RAM_DEPTH and what does the << operator do here.

May 7, 2013 · That use of ~ in the if statement is not very clear. I would always use ~ with a comparison. Also my simulator does not think Verilog and SystemVerilog are the same thing. Verilog is often used to refer to the 1995 or 2001 specs before SystemVerilog it makes a big difference to those using older tools. –

Jan 18, 2016 · assign is used for driving wire/net type declarations. Since wires change values according to the value driving them, whenever the operands on the RHS changes,the value is evaluated and assigned to LHS( thereby simulating a wire).

Verilog: Better syntax for many cases in a case structure. 2. Non-constant indexing for a logic statement ...

Apr 24, 2017 · I would use the following statement instead: assign mywire = ~0; in a simple expression like this, the width on the left-hand side of the assignment sets the width for the expression on the right hand side.