freebsd-dev/sys/boot/i386/kgzldr/sio.s
Robert Nordier 9e3377b8b3 Support a.out: avoid (%dx) in in/out instructions, and use an m4
macro to supply underscores for externals.
2000-11-04 13:03:52 +00:00

47 lines
1.9 KiB
ArmAsm

#
# Copyright (c) 1999 Global Technology Associates, Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
# OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# From: sio.s 1.3 1999/01/10 14:48:03 rnordier
# $FreeBSD$
#
.set SIO_PRT,SIOPRT # Base port
.globl _(sio_putchr)
# void sio_putchr(int c)
_(sio_putchr): movw $SIO_PRT+0x5,%dx # Line status reg
xor %ecx,%ecx # Timeout
movb $0x40,%ch # counter
sio_putchr.1: inb %dx,%al # Transmitter
testb $0x20,%al # buffer empty?
loopz sio_putchr.1 # No
jz sio_putchr.2 # If timeout
movb 0x4(%esp,1),%al # Get character
subb $0x5,%dl # Transmitter hold reg
outb %al,%dx # Write character
sio_putchr.2: ret # To caller