How do you input an array in Verilog?

Verilog does not support two dimensional arrays as ports of modules. This feature is supported by SystemVerilog only. In the first snippet, you are passing two dimensional array a as input, which is not supported. In the latter case, a single dimensional vector is passed to the module which works fine.

How do you initialize a packed array in Verilog?

Remember, b[7:0] means an array of eight 1-bit numbers. In your example you are trying to initialise it with a single 8-bit number, which is not the same thing. For Verilog, you have to initialise each element in the array one by one: b[0] = 1’b0; b[1] = 1’b0; b[2] = …

How do I slice an array in SystemVerilog?

When accessing a range of indices (a slice) of a SystemVerilog array, you can specify a variable slice by using the [start+:increment width] and [start-:decrement width] notations. They are simpler than needing to calculate the exact start and end indices when selecting a variable slice.

What is packed array in SystemVerilog?

There are two types of arrays in SystemVerilog – packed and unpacked arrays. A packed array is used to refer to dimensions declared before the variable name. bit [3:0] data; // Packed array or vector logic queue [9:0]; // Unpacked array. A packed array is guaranteed to be represented as a contiguous set of bits.

What is array in Verilog?

An array is a collection of the same types of variables and accessed using the same name plus one or more indices. Each array dimension is declared by having the min and max indices within the square brackets. Array indices can be written in either direction: array_name[least_significant_index:most_significant_index]

How do arrays work in Verilog?

Verilog arrays can only be referenced one element at a time. Therefore, an array has to be copied a single element at a time. Array initialization has to happen a single element at a time. It is possible, however, to loop through array elements with a generate or similar loop construct.

What is packed array?

A packed array is a mechanism for subdividing a vector into subfields which can be conveniently accessed as array elements. Consequently, a packed array is guaranteed to be represented as a contiguous set of bits. An unpacked array may or may not be so represented.

Are arrays synthesizable?

Array lists are synthesizable. The number of array dimensions and the number of values in the array list must be identical. The number of bits of each element must also be the same size as the values in the list.

What are packed arrays?

What is alias in SystemVerilog?

It is a way of providing a more user friendly name for another signal, or a select of another signal. The alias construct provides one other feature that is to connect two different nets together without knowing the direction of data flow. That avoids extraneous buffers or assign statements.

What are vectors in Verilog?

Vector Data Verilog provides the concept of Vectors. Vectors are used to represent multi-bit busses. In which case the LSB will be represented by leftmost bit. Let us rewrite our comparator example, so that it now use two bit bus in place of one bit.