The "alarm" pseudo-element
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Abstract

The "alarm" pseudo-element senses a circuit condition requiring the
user to be notified, and sends notice of the event.
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Syntax
	alarm <name> <expression> <message>
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BNF

alarm: 'alarm' name logic_expression message'\n'
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Description

The alarm is similar to a trigger, but is used only externally, to
indicate that something is wrong.

The alarm is activated whenever the <expression> evaluates to true.
It is intended that alarms operate in the background unless the
condition is activated.  At this point, the simulator should indicate
that an alarm condition has occurred, by displaying the attached message.
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Uses in IBIS 3.2

The "overshoot" conditions represent conditions that may lead to
failure or improper operation.  The alarm is used in IBIS 3.2 to alert 
the user that failure may occur.
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Example

alarm failure  (V(pin) > D_overshoot_high ||
		V(pin) < D_overshoot_low  ||
		V(pin) > S_overshoot_high for D_overshoot_time ||
		V(pin) < S_overshoot_low  for D_overshoot_time ||
		never)   "unsafe input voltage overshoot"

In the example here, the alarm is activated when certain overvoltage
conditions exist, for example v(pin) exceeds its limit
"D_overshoot_high", or it exceeds "S_overshoot_high" for a time
exceeding "D_overshoot_time".
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