ack/lang/b/compiler/em_b.6
George Koehler f91bc2804d Tune the installed manual pages.
This commit slightly improves the formatting of the manuals.  My
OpenBSD machine uses mandoc(1) to format manuals.  I check the manuals
with `mandoc -T lint` and fix most of the warnings.  I also make
other changes where mandoc didn't warn me.

roff(7) says, "Each sentence should terminate at the end of an input
line," but we often forgot this rule.  I insert some newlines after
sentences that had ended mid-line.

roff(7) also says that blank lines "are only permitted within literal
contexts."  I delete blank lines.  This removes some extra blank lines
from mandoc's output.  If I do want a blank line in the output, I call
".sp 1" to make it in man(7).  If I want a blank line in the source,
but not the output, I put a plain dot "." so roff ignores it.

Hyphens used for command-line options, like \-a, should be escaped by
a backslash.  I insert a few missing backslashes.

mandoc warns if the date in .TH doesn't look like a date.  Our manuals
had a missing date or the RCS keyword "$Revision$".  Git doesn't
expand RCS keywords.  I put in today's date, 2017-01-18.

Some manuals used tab characters in filled mode.  That doesn't work.
I use .nf to turn off filled mode, or I use .IP in man(7) to make the
indentation without a tab character.

ack(1) defined a macro .SB but never used it, so I delete the
definition.  I also remove a call to the missing macro .RF.

mandoc warns about empty paragraphs.  I deleted them.  mandoc also
warned about these macro pairs in anm(1):

    .SM
    .B text

The .SM did nothing because the .B text is on a different line.  I
changed each pair to .SB for small bold text.

I make a few other small changes.
2017-01-18 23:02:30 -05:00

54 lines
1.7 KiB
Groff

.TH EM_B 6 2017-01-18
.ad
.SH NAME
em_b \- ACK B compiler
.SH SYNOPSIS
.B ~em/lib/ack/em_b
.RI [ options ]
.SH DESCRIPTION
.I em_b
is a port of the ABC B compiler to the ACK.
Interested parties will be
interested in the upstream distribution here:
.nf
.sp
https://github.com/aap/abc
.fi
.PP
However, the version here has been heavily modified \(em bug reports should be
filed with the ACK, not with the upstream compiler.
.PP
Since B was designed for machines with word addressing, some hacking is
required to make it work on modern, byte addressed machines.
The generated
code expects B variables to contain word addresses, and then generates
code to transform these into native addresses before use (which,
unfortunately, impacts performance).
However, the ACK's linker doesn't know
how to emit word addresses into the program's data sections, and so a
separate fixup stage has to happen at runtime, just before \fBmain()\fP,
to convert the byte addresses into word addresses.
.PP
The end result is that using multiple source files with B is somewhat
unwieldy, requiring each module to be explicitly named and then an extra
stage to generate the fixup code.
See the \fBack\fP(1) and \fBabmodules\fP(1) for details.
.SH OPTIONS
.I em_b
accepts the following flags:
.IP \-w\ \fIsize\fP
Sets the word size, used for scaling addresses.
Usually either 2 or 4.
.IP \-B\ \fIname\fP
Sets the name of the module currently being compiled (used to generate the
fixup table symbol name).
Defaults to \fImain\fP if not specified.
.IP \-i\ \fIfilename\fP
The source B file.
.IP \-o\ \fIfilename\fP
The output compact EM bytecode file.
.SH SEE ALSO
\fIack\fR(1), \fIabmodules\fR(1)
.SH REMARKS
It is very unlikely the \fIem_b\fP will ever be useful for anything.