76 lines
2.6 KiB
Groff
76 lines
2.6 KiB
Groff
.\" $Header$
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.TH EM 1 "$Revision$"
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.ad
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.SH NAME
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em \- calling program for em interpreters
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.SH SYNOPSIS
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\fBem\fP [-t] [+fcp] [loadfile [args ... ...] ]
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.SH DESCRIPTION
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The loadfile ("e.out" if not specified) is opened to read the first 8 word header.
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The format of this header is explained in e.out(5).
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One of these 8 words is a flag word
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specifying the interpreter options requested at compile time.
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The usual setting of these options is +t -f -c -p.
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One of these options may be overridden at run time
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by the corresponding flag of em.
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Based on these options the name of the appropriate interpreter
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is constructed.
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.PP
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The flags control the following options that can be turned off
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or on by prepending them with - or + respectively:
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.IP t
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run time tests for undefined variables, array bounds etc...
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This option costs a small amount of memory and some time.
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However, it is very useful for debugging.
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.IP p
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profiling of the entire program. The interpreter maintain tables containing
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an estimate of the number of memory cycles used per source line.
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This option is expensive in time as well as in memory space.
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The result tables made at run time are dumped onto a file named
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em_runinf. This file is converted to human readable format
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by the program eminform(1) which writes the profiling information
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on a file called em_profile.
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.IP f
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maintain a bit map of all source lines that have been executed.
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This map is written also onto the file em_runinf and can be interpreted by eminform(1) which writes in this case the file em_flow.
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This option is almost free in time and space.
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.IP c
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count line usage in tables that
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contains for every source line the number of times it
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was entered.
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These tables are also written onto em_runinf.
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Eminform(1) can be used to convert this information into the
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file em_count.
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Cheap in time, expensive in memory space.
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.PP
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These flags
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give rise to 5 different interpreters which are in the
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directory ~em/lib/em22/em_????
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.PP
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If the interpreter exits with a non-zero exit status, then the line numbers
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of the 64 last executed source lines are dumped on the file
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em_runinf
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in the current directory. Eminform(1) writes this information
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on the human readable file em_last.
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.SH "FILES"
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.IP ~em/lib/em22/em_???? 35
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interpreters proper
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.IP em_runinf
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memory dump containing runtime information
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.IP em_profile
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profile data
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.IP em_count
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source line count data
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.IP em_flow
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source line flow data
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.IP em_last
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last lines executed
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.PD
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.SH "SEE ALSO"
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eminform(1), ack(1),
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.SH BUGS
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Most error messages are self explanatory.
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The interpreter stops in case of lack of space with an error
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message SEGVIO stack overflow.
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If runtime flags are turned on it is advisable to try again
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with the default options.
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