====== Assertion ======
===== assertion_statement =====
<code vhdl>
[ label : ] assertion ;
</code>

===== Parents =====
  * function_statement_part
  * procedure_statement_part
  * process_statement_part

===== Further definitions =====
==== assertion ====
''**assert** [[.:bnf#condition]]''

''[ **report** expression ]''

''[ **severity** expression ]''

==== condition ====
''//boolean// _[[.:bnf#expression]]''

==== expression ====
  * [[.:bnf#relation]] { and relation }
  * relation { or relation }
  * relation { xor relation }
  * relation [ nand relation ]
  * relation [ nor relation ]
  * relation { xnor relation }

===== Comments =====
The **REPORT** expression have to be of type string.

In absence of the **REPORT** clause the default string "Assertion Violation." will be used.

The **SEVERITY** expression have be of type severity_level. Possible values are: note, warning, error, failure.

In absence of the **SEVERITY** clause the default error will be used.

===== Examples =====
It is checked whether //signal_reset// is not equal to //1// .
<code vhdl>
ASSERT signal_reset = '1' ;
</code>

----

If //variable_reset// is not equal to //1// the report ``Reset is active`` is given.
<code vhdl>
ASSERT variable_reset = '1'
REPORT "Reset is active !" ;
</code>

----

If the condition which is to be verified is not fulfilled an error is reported and measures in accordance with the severity level are taken.
<code vhdl>
ASSERT reset = '1' OR set = '1'
  REPORT "Reset and Set" &
         "simultaneously active !"
  SEVERITY failure ;
</code>

----

If //data// is not equal to //0// a severity note containing the current value of //data// is given.
<code vhdl>
ASSERT data = 0
REPORT "Datum ist gleich " &
      integer_to_string( data ) & " !"
SEVERITY note ;
</code>

----

This assertion automatically (false) stops (severity_level = failure) the simulation at the time evaluated
<code vhdl>
ASSERT false
REPORT "End of simulation!"
SEVERITY failure ;
</code>