Relational operators in VHDL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are relational operators in VHDL?

Relational operators in VHDL compare two values and return a Boolean result: TRUE or FALSE. They help decide if one value is equal to, greater than, or less than another.

beginner

List the common relational operators used in VHDL.

The common relational operators are: = (equal), /= (not equal), < (less than), <= (less than or equal), > (greater than), >= (greater than or equal).

beginner

What is the result type of a relational operator in VHDL?

The result of a relational operator is a Boolean value: TRUE if the comparison is correct, FALSE if it is not.

beginner

How would you compare two signals A and B to check if A is greater than B in VHDL?

You use the > operator like this: A > B. This returns TRUE if A is greater than B, otherwise FALSE.

intermediate

Can relational operators be used with all data types in VHDL?

Relational operators work with many data types like integers, std_logic_vectors (with proper libraries), and enumerated types, but not all types support all operators directly.

Which operator checks if two values are not equal in VHDL?

A /=

B =

C <>

D !=

In VHDL, '/=' means not equal. '<>' and '!=' are not valid operators in VHDL.

What type of value does a relational operator return?

A Real

B Integer

C String

D Boolean

Relational operators return a Boolean value: TRUE or FALSE.

Which operator would you use to check if A is less than or equal to B?

A >=

B <

C <=

D =>

'<=' means less than or equal in VHDL.

Is the following statement valid in VHDL? A = B

A Yes, it checks if A equals B

B No, '=' is not a relational operator

C No, it assigns B to A

D Yes, it assigns B to A

'=' is the equality relational operator in VHDL, used to compare values.

Which relational operator means 'greater than or equal to'?

A <=

B >=

C =>

D ><

'>=' means greater than or equal to in VHDL.

Explain what relational operators are and list the main ones used in VHDL.

Think about how you compare two numbers or signals.

Describe the result type of relational operators and give an example of how to use one in VHDL.

What do you get when you ask if one value is bigger than another?