Comparescan User Guide
Writing Comparescan Rules
Command Syntax and Options
The following sections describe the commands that you can use in the rules file that you specify with a given comparison. General command syntax and options are described first, followed by specific syntax, options, and examples for each command.
General Command Syntax
Comparescan rules have the form:
command arguments [options] [{#|//} comment]
Arguments are usually module names or signal names that you want to compare.
Options set the values for comparison parameters. For example, to change the setup time from the default of 0 to 20ns, use the option -setup 20ns.
Comments begin with a comment character (# or //) and continue to the end of the line.
Example
The following rule compares two signals, with a tolerance window of 35ns. The signal names are arguments, and the tolerance setting is an option.
compare top.signal1 top.signal2 -tol 35ns # sample rule
Implied Arguments
Sometimes arguments can be implied so that you do not have to explicitly enter them. For example, if you specify only one object for comparison, Comparescan looks for an object that has the same name in each of the files that you are comparing.
//Implied arguments. The following two rules are equivalent: compare top.signal1 top.signal1
compare top.signal1
//Similarly, the following two rules are equivalent: clkcompare top.clk top.signal1 top.clk top.signal1 clkcompare top.clk top.signal1
Option Order
You can specify options in any order.
// Option order. The following two rules are equivalent:
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compare top.signal1 -setup 10 -hold 20 compare top.signal1 -hold 20 -setup 10
// Similarly, the following two rules are equivalent: datafile1 golden.trn -start 300 -end 2000
datafile1 golden.trn -end 2000 -start 300
Commenting
A comment begins with a comment character: either # or //. A comment can begin at the beginning of a line or at the end of a rule. Comparescan ignores all text from a comment character to the end of that line.
# Comment to the end of the line. // Comment to the end of the line.
datafile1 golden.trn # Comment to the end of the line. datafile2 test.trn // Comment to the end of the line.
Continuing Long Lines
Use a backslash character (\) at the end of a line to continue that statement on the next line. The backslash must be the last character on the continued line.
compare top.module1.module2.module25.signalA \
top.module1.module4.module25.signalZ \
-neg 10 -pos 20 // These three lines are all one rule.
Command Summary
Table 6-1 on page 59 lists all of the Comparescan commands that you can use in rules files.
Table 6-1 Comparescan Rules File Commands
Command |
Description |
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datafile1 |
Specifies the golden simulation file. |
datafile2 |
Specifies the secondary or test simulation file. |
compare |
Performs an event-matching comparison. Every event in the |
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golden simulation must match an event in the test simulation. |
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You can specify a tolerance window to facilitate this type of |
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matching. |
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Table 6-1 Comparescan Rules File Commands |
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Command |
Description |
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clkdef |
Defines a name for a clock that you want to use in a clock |
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comparison. |
clkcompare |
Performs a clock-edge sample comparison and stability |
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check. A clock compare is very useful for comparing signals |
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that have many uninteresting transitions before stabilizing. |
stability |
Performs a clock-edge stability check, but does not perform a |
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clock-edge sample comparison. |
sequencetime |
Includes sequence time in the event stream. |
nosequencetime |
Ignores sequence time events. |
report |
Generates ASCII comparison reports. |
savedata |
Saves the error database into a file for later viewing. |
loaddata |
Loads the error database into a Comparescan window for |
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viewing. |
statemapping |
Defines a mapping between logic states. |
threshold |
Defines a mapping from analog values to logic states. |
translate |
Translates a simulation results database file to SST2 |
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database format. |
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General Command Options
Option values that you specify in a Comparescan rules file override any option values that you specify on the Compare Options form.
Note: To ensure that the your comparison behaves in the same way each time you run it, you should specify all of the options for a comparison in a rules file.
You may want to use the Compare Options form to create global option settings that apply to all rules for which you have not set some other value in the rules file.
Comparescan applies the option values that you specify in a rules file according to an algorithm. See “Setting compare Command Options” on page 71 and “Setting clkcompare Command Options” on page 79 for a description of this algorithm.
You can use the options that are listed below with any command in the rules file. Options that apply only to specific commands are described in the sections for those commands below.
Table 6-2 Global Options
Option |
Description |
Default Value |
-maxerrors N
(Error Count Limit Per Signal on the Compare Options form)
-totalerrors N
(Error Count Limit on the Compare Options form)
Stop processing a signal when N errors |
-maxerrors 10 |
are found on that signal. Processing |
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continues with the next signal or rule. |
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-maxerrors 0 means report all of the |
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errors on each signal. |
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Stop processing the rules file when N |
-totalerrors 100 |
errors are found. Rules file processing |
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does not continue, and the comparison |
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ends. |
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-totalerrors 0 means report all |
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errors. |
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-start N |
Specifies the simulation time at which |
-start |
(Start Time on the |
the comparison begins. |
SimStartTime |
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Compare Options form) |
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-end N |
Specifies the simulation time at which |
-end SimEndTime |
(End Time on the |
the comparison stops. |
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Compare Options form) |
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Table 6-2 Global Options, continued
Option |
Description |
Default Value |
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-shift N |
Specifies the amount by which the time |
-shift 0 |
(Time Shift on the |
is shifted. |
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Compare Options form) |
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-shift1 N |
Specifies the amount by which the time |
-shift1 0 |
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is shifted in the golden simulation. |
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-shift2 N |
Specifies the amount by which the time |
-shift2 0 |
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is shifted in the test simulation. |
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-clockshift N |
Specifies the amount by which the time |
-clockshift 0 |
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is shifted for the clocks that are defined |
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within a clkcompare command. |
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This option shifts the times in both the |
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golden file and the test file. |
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-clock1shift N |
Specifies the amount by which the time |
-clock1shift 0 |
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is shifted for the clocks that are defined |
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in the golden file. |
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-clock2shift N |
Specifies the amount by which the time |
-clock2shift 0 |
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is shifted for the clocks that are defined |
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in the test file. |
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-ignorestrength |
Specifies that this comparison ignores |
-ignorestrength |
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all signal strengths. |
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-checkstrength |
Specifies that this comparison requires |
-ignorestrength |
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all signal strengths to match exactly. |
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-tol N |
Specifies both the positive and negative |
-tol 0 |
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tolerance for a matching event. |
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The tolerance is the window of time |
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during which a signal may match. The |
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default positive and negative tolerance |
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is 0. This means that by default, each |
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golden event must match each test |
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event exactly. |
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Table 6-2 Global Options, continued
Option |
Description |
Default Value |
-pos N
(Positive Tolerance on the Compare Options form)
-neg N
(Negative Tolerance on the Compare Options form)
Specifies the positive tolerance for a -pos 15 matching event. This is the window of
time after a golden event during which a test event may match.
Specifies the negative tolerance for a -neg 15 matching event. This is the window of
time before a golden event during which a test event may match.
Specifying Units on Time Options
You can specify time units whenever you specify a time. If you do not specify units with a given time, Comparescan uses the simulation time unit setting for that time. For a list of the valid time units that you can specify, see Table 6-3 on page 63.
Note: If the timescale of a simulation is larger than the result of a timescaled option value, Comparescan reads that time value as zero. For example, if the simulation timescale is in seconds, and you specify the option -pos 10ms, the actual time value that Comparescan uses is 0.
Below are some examples of the use of time units in a rules file:
compare top.signal -tol 20ns
clkdef clk top.clk -sample 15ns
clkcompare top.clk top -pos 10ps -neg 100ps
Use the strings that are shown in the Time Unit column below with your time options.
Table 6-3 Time Units and Scale Factors
Time |
Time Unit |
Power of Ten |
|
|
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attoseconds |
as |
-18 |
femtoseconds |
fs |
-15 |
picoseconds |
ps |
-12 |
nanoseconds |
ns |
-9 |
microseconds |
us |
-6 |
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Table 6-3 Time Units and Scale Factors, continued |
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Time |
Time Unit |
Power of Ten |
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milliseconds |
ms |
-3 |
centiseconds |
cs |
-2 |
deciseconds |
ds |
-1 |
seconds |
s |
0 |
decaseconds |
Ds |
1 |
hectoseconds |
hs |
2 |
kiloseconds |
ks |
3 |
megaseconds |
Ms |
6 |
gigaseconds |
Gs |
9 |
teraseconds |
Ts |
12 |
petaseconds |
Ps |
15 |
exaseconds |
Es |
18 |
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