Hardware Reference
In-Depth Information
Chapter 11
Advanced Sequences
Poe's saying that a long poem is a sequence of short ones is
perfectly just.
—
John Drinkwater
In Chap.
6
, we covered basic sequence operators, such as delays, consecutive
repetition and disjunction. In this chapter, we learn about the remaining sequence
operators. Although these remaining operators do not add any additional expres-
sive power to the language, they are very convenient to use, and make assertions
more readable and concise. We also consider sequence methods and discuss using
sequences as events.
In examples throughout this chapter, we assume that a
default clocking
is
defined, and thus omit the clock in assertions unless there is a need to emphasize a
specific clock usage. We assume that
e
is a Boolean,
r
and
s
are sequences, and
p
is
a property.
11.1
Sequence Operators
The available sequence operators grouped by their precedence from highest to
lowest are listed in Table
11.1
. For convenience, we also list here the operators
covered in Chap.
6
.
11.1.1
Throughout
Sometimes it is necessary to make sure that a Boolean condition holds throughout
the whole sequence. For this purpose, it is possible to use the sequence operator
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