Initial import from FreeBSD RELENG_4:
[dragonfly.git] / sys / boot / i386 / kgzldr / sio.s
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1#
2# Copyright (c) 1999 Global Technology Associates, Inc.
3# All rights reserved.
4#
5# Redistribution and use in source and binary forms, with or without
6# modification, are permitted provided that the following conditions
7# are met:
8# 1. Redistributions of source code must retain the above copyright
9# notice, this list of conditions and the following disclaimer.
10# 2. Redistributions in binary form must reproduce the above copyright
11# notice, this list of conditions and the following disclaimer in the
12# documentation and/or other materials provided with the distribution.
13#
14# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
15# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
18# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
19# OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
20# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
21# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
23# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
24# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25#
26# From: sio.s 1.3 1999/01/10 14:48:03 rnordier
27# $FreeBSD: src/sys/boot/i386/kgzldr/sio.s,v 1.2 1999/08/28 00:40:11 peter Exp $
28#
29
30 .set SIO_PRT,SIOPRT # Base port
31
32 .globl sio_putchr
33
34# void sio_putchr(int c)
35
36sio_putchr: movw $SIO_PRT+0x5,%dx # Line status reg
37 xor %ecx,%ecx # Timeout
38 movb $0x40,%ch # counter
39sio_putchr.1: inb (%dx),%al # Transmitter
40 testb $0x20,%al # buffer empty?
41 loopz sio_putchr.1 # No
42 jz sio_putchr.2 # If timeout
43 movb 0x4(%esp,1),%al # Get character
44 subb $0x5,%dl # Transmitter hold reg
45 outb %al,(%dx) # Write character
46sio_putchr.2: ret # To caller