sio.s revision 68314
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: head/sys/boot/i386/kgzldr/sio.s 68314 2000-11-04 13:03:52Z rnordier $ 28# 29 30 .set SIO_PRT,SIOPRT # Base port 31 32 .globl _(sio_putchr) 33 34# void sio_putchr(int c) 35 36_(sio_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 47