The VHDL language has a set of standard operators that can be used to perform comparisons, form boolean equations and perform arithmetic. This set of operators is the toolkit that is used to build up RTL models.
This chapter introduces the built-in operators and what they do, with an explanation of the rules that VHDL uses to decide the order of precedence when calculating a complicated expression.
5.1 The Standard Operators
The full set of operators in VHDL is listed here:
|xor||exclusive-or function (bitwise inequality)|
|xnor||exclusive-nor function (bitwise equality)|
|>=||greater-than or equal|
|<=||less-than or equal|
|rem||remainder after division|
5.2 Operator Precedence
Operators are classified by the standard as logical, relational, adding, sign, multiplying and miscellaneous. The reason for classifying the operators is to allow for operator precedence. This is not the same classification I have used in the rest of the book, which is simpler and groups operators by what they do, rather ...