Enumerated types

Type constants can be used to describe what are traditionally treated as enumerated types. To introduce a type Color whose legal values are red, blue, and yellow,... 

Events are fundamentally about changes of state, not about constraints on state. Enumeration Types... 

UML/OCL has an enumeration type and a separate concept of class attributes. In Catalysis we use shared attributes on a type, with an invariant, to provide enumeration types. 

The simple idea behind the post-synthesis verification procedure is a3 follows. A concrete specification and a concrete synthesis result are defined by introducing the enumeration types for OPS,. .., BUSS and by introducing the definitions of the hardware model functions flow,. .., ball. The properties are first order terms with quantifications over finite sets represented by enumeration types and over natural numbers representing control steps. We have proved a theorem that allows to replace each quantification over natural numbers by a quantification over the finite set of operations. So all quantifications reach over finite sets. Each 3-quantification is replaced by a disjunction and each V-quantification is replaced by a conjunction. The remaining terms are boolean terms and applications of hardware model functions to constants of enumeration types or constant natural numbers. Rewriting with the definitions of the model functions reduce the applications to constants. What remains are comparisons of constants which are replaced by truth values. Final rewriting completes the proof. 

Cause Enumeration Type All possible causes are listed using brainstorming techniques. 

SecAM Library Basic SECA Types Enumeration Types... 

Besides the requirement to support 7 hardware platforms, the system s compile-time configuration can be also affected by approximately 65 configuration options, most of which are booleans, the rest are enumerated types. 

To model automata locations and messages, two enumeration types are defined. Moreover, a type for timing parameters is introduced as the set of nonnegative reals, and a subrange is introduced to serve as an index for messages in the charmel. 

Example 2,9 Enumerated Types Using the enum encoding Attribute... 

This function takes in the enumerated type tap states and... 

The function converts the enumerated type tap states defined above to "String so that one can then use the write procedure from the textio --package. 

An enumeration type is a set of identifiers or characters that each represent a unique numeric value. The following predefined enumeration types are stored in the STANDARD package. 

Each enumeration literal represents a different value, and this value is determined by the position of the literal in the set. The first in the list is assigned the value 0, the second 1, and so on. In the synthesizer, these values are of course implemented in their binary form. Hence, an enumeration type containing four literals is represented by two bits, but five literals would require three bits. 

An object mtist be declared to be certain type. Integer and enumeration types are available. These can be formed from a single element - a scalar type - or multiple elements - a composite type. A composite type can be organized as an array or a record. 

Ordering operations can be performed on operands that are scalars or arrays composed of integer or enumeration type elements. For the less than condition to be TRUE, any one of the following must hold. 

The synthesizer sees 1001 and 1100 as arrays of flie enumerate type BIT, not as a direct and interchangeable representation of the discrete integer values 9 and 12. Note however that if S was declared as enumerate type CODES, which itself was defined as ... 

Another problem will arise if different versions of the operator function exist for enumeration types which contain literals that are identical. The... 

An ambiguous statement can arise if it is not possible to determine which enumeration type is being used. One consequence of this is tfiat the syntihesizer may not be able to determine which version of a subprogram is being called. This often occurs when a function or operator has been overloaded. Consider the package PARITY FUNCTIONS 2 shown below. 

Thus, the Decoder has been implemented as a component. Figure 7.4 shows the VHDL description of this circuit, which demonstrates how to construct a state machine. It is always advisable to use enumerate type encoding for states as shown in the architecture s declarative part. This example has eight states, inferring three storage elements and using all possible permutations of 0 and I. The present state is stored on a signal PRESENTSTATE that is visible only to this architecture. 

Figure 7.6 Package for the user-defined enumerate type and encoding scheme.

A composite type is an enumeration type, a fixed structure type, a list type or a class type. 

An enumeration type is a finite enumeration of constants. The enumeration type is denoted by the sequence ENUM(e1,. ..eN) where N denotes the cardinal number of the enumeration type and el,. ..eN denote the constant elements of the enumeration type. N has to be greater than 1. Than a structure attribute (parameter) of enumeration type E has any constant element of E as value. Enumeration type are members of the type class ATTRIBUTE. 

Analogous to the enumeration type definition (see "Enumeration types" on page 25) a class type is a finite enumeration of types. The sequence... 

There are generic structure types, generic enumeration types, generic class types and generic list types. A generic type is denoted by the sequence... 

In contrast to a eniuneration type (see "Enumeration types" on page 25), at least one of the value elements of a parametric enumeration type is a generic parameter. 

In case of a generic structure, PARAMETRIC TYPE is either a parametric fixed structure or a variant structure. The parameter types have to be class types (see Classes on page 28) or, in case of a generic variant structure, enumeration types. 

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