Announcing OSVVM™ 2015.01
OSVVM 2015.01 is a major release that introduces AlertLogPkg. AlertLogPkg adds Alert and verbosity control procedures that are a powerful replacement for assert statements. All OSVVM packages have replaced asserts with alerts.
VHDL assert statements have a limited form of an alert and verbosity control. Through a simulator, you can set an assertion level that will stop a simulation. Through a simulator, you can turn off some assertions from printing. However, none of this capability can be configured in VHDL, and in addition, at the end of a test, there is no way to retrieve a count of the various assertions that have occurred.
The AlertLogPkg provides Alert and Log procedures that replace VHDL assert statements and gives VHDL direct access to enabling and disabling of features, retrieving alert counts, and set stop counts (limits). All of these features can be used in either a simple global mode or a hierarchy of alerts.
Similar to VHDL assert statements, Alerts have values FAILURE, ERROR, and WARNING. Each is counted and tracked in an internal data structure. Within the data structure, each of these can be enabled or disabled. A test can be stopped if an alert value has been signaled too many times. Stop values for each counter can be set. The default for FAILURE is 0 and ERROR and WARNING are integer’right. If all test errors are reported as an alert, at the end of the test, a report can be generated which provides pass/fail and a count of the different alert values.
What differentiates AlertLogPkg from other alert and verbosity filtering packages is hierarchical alerts. Hierarchical alerts allow alerts for each model and/or each source of alerts to be accumulated and reported separately. While the whole testbench will benefit from all models using alerts, a single model can effectively use either global or hierarchical alerts.
Logs provide a mechanism for verbosity control on printing. Through simulator settings, assert has this capability to a limited degree. Verbosity control allows messages (such as debug, DO254 final test reports, or info) that are too detailed for normal testing to be printed when specifically enabled.
OSVVM 2015.01 also introduces TranscriptPkg. TranscriptPkg provides a mechanism to share a transcript file across the entire testbench. TranscriptPkg provides a shared file, TranscriptFile, and procedures TranscriptOpen, TranscriptClose, print, and writeline. Print and WriteLine print to TranscriptFile when the transcript file is open, otherwise, print to std.textio.OUTPUT. AlertLogPkg uses TranscriptPkg for all of its printing. CoveragePkg uses TranscriptPkg for all of its printing that previously went to std.textio.OUTPUT.
OSVVM 2015.01 also introduces OsvvmGlobalPkg. OsvvmGlobalPkg provides a means to set global parameters for coverage models and the AlertLogPkg.
All of the OSVVM packages have detailed user guides in the doc directory of the release. OSVVM 2015.01 is available in the download area.
There are also other Alert and verbosity control packages available. By editing the package body of AlertLogPkg, OSVVM can be configured to use the other package. By interfacing to the separate packages via the package body, only the package body needs to be recompiled and not the entire OSVVM library.