Basic principles of VHDL arithmetic

The structural style of creating an architecture allows the designer to specify explicitly  

On top of this, vendors supply libraries that contain circuit modules or macros that are designed to make die most efficient use of the resources in a particular technology or actual device. These modules can be instantiated as components. The drawback of vendor libraries is that the VHDL description is technology dependent and to target a different technology can involve a considerable redesign effort. The macro / module approach is particularly valuable for PPG A devices that have available a limited number of fixed function resources. 

The arithmetic operators in VHDL can operate on any predefined numeric type. For a synthesizeable design their use is dierefore limited to integer types. Box 6.1 illustrates ways of expressing synthesizeable numeric literals. The operators can be subdivided into die following classes. 

The concatenation operator is also classed as an adding operator. This was covered in Chapter 5. The adding operators have the lowest precedence and the miscellaneous operators have die highest. 

In order that the complexity of arithmetic hardware is constrained most s5mthesizers only allow power of 2 operations (2, where M is an integer) with the following operators. 

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