VHDL 1076-93/2000 Readme

Although the design goal for VHDL Simili has been full compliance with the VHDL standard, we have a few exceptions. Every VHDL compiler we know of has some such set of exceptions -- the difference is that we let you know what these exceptions are and hopefully we are not penalized for this honesty.

Each exception listed below is categorized to indicate as to when this exception is scheduled to be eliminated. In every instance, the compiler/simulator will issue and error and prevent wrong results from being produced. If one or more of these features are very important to you, please contact us so we can accelerate its incorporation.  Where the "Target Release" indicates "Undetermined", this means that we wish to implement these constructs but have not yet determined a timeframe.

VHDL 93 Construct Target Release
Disconnect statement not supported Undetermined
Individual associations to associate subprogram parameters not supported. However, individual port/generic associations ARE supported. We are not sure if any tool (commercial or otherwise) supports this.

No Plans

Type conversions on the formal part of the association for subprograms in the case where the parameter is of class SIGNAL. Most other tools do not support this either. Undetermined
The compiler does not currently check for the validity of the keyword PURE/IMPURE before a subprogram definition. However, from a simulation standpoint, the results will be correct. Undetermined
A concurrent procedure call made in an entity is not checked to ensure that it is passive (that it does not modify any signals). These functions however are executed correctly. Undetermined
The attributes 'INSTANCE_NAME and 'PATH_NAME are not allowed during elaboration (mainly in declaration sections in architectures). However, these attributes are compliant during simulation (after elaboration). As a result, use of these attributes in the declaration statements of entities and architectures will produce an error. However, using them anywhere else will produce the desired results. Undetermined
The attributes 'DRIVING and 'DRIVING_VALUE are not yet supported. These attributes attempt to query the driver of a given signal for information about the driver. This feature has been implemented but we are unsure about its accuracy under all circumstances and hence it is disabled. Undetermined
User defined resolution functions for composite types. Currently a user defined resolution function is only allowed on a scalar type. Undetermined