mirror of https://github.com/mkerrisk/man-pages
68 lines
2.4 KiB
Groff
68 lines
2.4 KiB
Groff
.\" Hey Emacs! This file is -*- nroff -*- source.
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.\"
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.\" Copyright (c) 1995 Paul Gortmaker
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.\" (gpg109@rsphy1.anu.edu.au)
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.\" Wed Nov 29 10:58:54 EST 1995
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.\"
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\"
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.\" The GNU General Public License's references to "object code"
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.\" and "executables" are to be interpreted as the output of any
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.\" document formatting or typesetting system, including
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.\" intermediate and printed output.
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.\"
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.\" This manual is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details.
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.\"
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.\" You should have received a copy of the GNU General Public
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.\" License along with this manual; if not, write to the Free
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.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
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.\" USA.
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.\"
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.\"
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.TH OUTB 2 1995-11-29 "Linux" "Linux Programmer's Manual"
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.SH NAME
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outb, outw, outl, outsb, outsw, outsl,
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inb, inw, inl, insb, insw, insl,
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outb_p, outw_p, outl_p, inb_p, inw_p, inl_p \- port I/O
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.sp
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.SH DESCRIPTION
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This family of functions is used to do low level port input and output.
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The out* functions do port output, the in* functions do port input;
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the b-suffix functions are byte-width and the w-suffix functions
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word-width; the _p-suffix functions pause until the I/O completes.
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.LP
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They are primarily designed for internal kernel use,
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but can be used from user space.
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.\" , given the following information
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.\" in addition to that given in
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.\" .BR outb (9).
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.sp
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You compile with \fB\-O\fP or \fB\-O2\fP or similar. The functions
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are defined as inline macros, and will not be substituted in without
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optimization enabled, causing unresolved references at link time.
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.sp
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You use
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.BR ioperm (2)
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or alternatively
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.BR iopl (2)
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to tell the kernel to allow the user space application to access the
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I/O ports in question. Failure to do this will cause the application
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to receive a segmentation fault.
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.SH "CONFORMING TO"
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\fBoutb\fP() and friends are hardware specific. The
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.I value
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argument is passed first and the
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.I port
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argument is passed second,
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which is the opposite order from most DOS implementations.
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.SH "SEE ALSO"
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.BR ioperm (2),
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.BR iopl (2)
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