.TH UNSTAB LOCAL
.UC 4
.SH NAME
unstab \- insert C source code into compiled assembly language
.SH SYNOPSIS
.BI cc " -g -S [-O]"
.IR "" file.c;
.BR "unstab" " file.s"
.SH DESCRIPTION
.PP
.B unstab
allows you to more easily see what assembly language is generated from
your C code by intermingling the C source code and the generated assembly
language into a single output file (for reading only).
.PP
Even if you can't fully understand the generated assembly language, it can be
quite helpful to see how much (or how little) your C code is generating.  If
you have a program which must run as fast as possible, looking at the code
generated in its innermost loops can be very helpful.
.PP
Note in the example below,
.I putc
is not the macro you might think it should be.
.SH EXAMPLE
.\" ### initiate asis block ###
.nr UU \n(.u   \"asis block ###
.nf            \"asis block ###
\&% \fBcat -n foo.c\fP
\&     \fI1  #include <stdio.h>\fP
\&     \fI2  main(){\fP
\&     \fI3      putc('a', stdout);\fP
\&     \fI4      fputc('b', stdout);\fP
\&     \fI5  }\fP
\&% \fBcc -g -O -S foo.c\fP
\&% \fBunstab foo.s\fP
\&(some initial cruft omitted)
\&main:
\&                     \fI1:#include <stdio.h>\fP
\&                     \fI2:main(){\fP
\&.LM1:
\&        pushl   %ebp
\&        movl    %esp, %ebp
\&        subl    $16, %esp
\&                     \fI3:    putc('a', stdout);\fP
\&.LM2:
\&        pushl   stdout
\&        pushl   $97
\&        call    _IO_putc
\&                     \fI4:    fputc('b', stdout);\fP
\&.LM3:
\&        addl    $8, %esp
\&        pushl   stdout
\&        pushl   $98
\&        call    fputc
\&                     \fI5:}\fP
\&.LM4:
\&        leave
\&        ret
\&(some trailing cruft omitted)
.if \n(UU .fi  \"asis block ###
.\" ### complete asis block ###
.SH SEE ALSO
.BR cc (1)
.SH AUTHOR
Corey Satten \- corey @ cac.washington.edu
.SH BUGS
.PP
The more optimization used in compilation, the less ordered the output.
.PP
A source line which appears out of sequence in the
.B unstab
output is only flagged with a negative line number.