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: btx.s 1.10 1999/02/25 16:27:41 rnordier
27# $FreeBSD$
28#
29
30# Screen defaults and assumptions.
31
32		.set SCR_MAT,0xe1		# Mode/attribute
33		.set SCR_COL,0x50		# Columns per row
34		.set SCR_ROW,0x19		# Rows per screen
35
36# BIOS Data Area locations.
37
38		.set BDA_POS,0x53e		# Cursor position
39
40		.globl crt_putchr
41
42# void crt_putchr(int c)
43
44crt_putchr: 	movb 0x4(%esp,1),%al		# Get character
45		pusha				# Save
46		xorl %ecx,%ecx			# Zero for loops
47		movb $SCR_MAT,%ah		# Mode/attribute
48		movl $BDA_POS,%ebx		# BDA pointer
49		movw (%ebx),%dx 		# Cursor position
50		movl $0xa0000,%edi
51crt_putchr.1:	cmpb $0xa,%al			# New line?
52		je crt_putchr.2			# Yes
53		movw %dx,%cx
54		movb %al,(%edi,%ecx,1)		# Write char
55		addl $0x2000,%ecx
56		movb %ah,(%edi,%ecx,1)		# Write attr
57		addw $0x02,%dx
58		jmp crt_putchr.3
59crt_putchr.2:	movw %dx,%ax
60		movb $SCR_COL*2,%dl
61		div %dl
62		incb %al
63		mul %dl
64		movw %ax,%dx
65crt_putchr.3:	cmpw $SCR_ROW*SCR_COL*2,%dx
66		jb crt_putchr.4			# No
67		leal 2*SCR_COL(%edi),%esi	# New top line
68		movw $(SCR_ROW-1)*SCR_COL/2,%cx # Words to move
69		rep				# Scroll
70		movsl				#  screen
71		movb $' ',%al			# Space
72		xorb %ah,%ah
73		movb $SCR_COL,%cl		# Columns to clear
74		rep				# Clear
75		stosw				#  line
76		movw $(SCR_ROW-1)*SCR_COL*2,%dx
77crt_putchr.4:	movw %dx,(%ebx) 		# Update position
78		shrw $1,%dx
79crt_putchr.5:	inb $0x60,%al			# Move cursor
80		testb $0x04,%al
81		jz crt_putchr.5
82		movb $0x49,%al
83		outb %al,$0x62
84		movb %dl,%al
85		outb %al,$0x60
86		movb %dh,%al
87		outb %al,$0x60
88		popa				# Restore
89		ret				# To caller
90