i915kms.4: Add missing space.
[dragonfly.git] / sys / boot / pc32 / kgzldr / crt.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: btx.s 1.10 1999/02/25 16:27:41 rnordier
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MD
27# $FreeBSD: src/sys/boot/i386/kgzldr/crt.s,v 1.4 2002/09/17 01:48:55 peter Exp $
28# $DragonFly: src/sys/boot/pc32/kgzldr/crt.s,v 1.3 2003/11/10 06:08:35 dillon Exp $
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29#
30
31# Screen defaults and assumptions.
32
33 .set SCR_MAT,0x7 # Mode/attribute
34 .set SCR_COL,0x50 # Columns per row
35 .set SCR_ROW,0x19 # Rows per screen
36
37# BIOS Data Area locations.
38
39 .set BDA_SCR,0x449 # Video mode
40 .set BDA_POS,0x450 # Cursor position
41
42 .globl crt_putchr
43
44# void crt_putchr(int c)
45
46crt_putchr: movb 0x4(%esp,1),%al # Get character
47 pusha # Save
48 xorl %ecx,%ecx # Zero for loops
49 movb $SCR_MAT,%ah # Mode/attribute
50 movl $BDA_POS,%ebx # BDA pointer
51 movw (%ebx),%dx # Cursor position
52 movl $0xb8000,%edi # Regen buffer (color)
53 cmpb %ah,BDA_SCR-BDA_POS(%ebx) # Mono mode?
54 jne crt_putchr.1 # No
55 xorw %di,%di # Regen buffer (mono)
56crt_putchr.1: cmpb $0xa,%al # New line?
57 je crt_putchr.2 # Yes
58 xchgl %eax,%ecx # Save char
59 movb $SCR_COL,%al # Columns per row
60 mulb %dh # * row position
61 addb %dl,%al # + column
62 adcb $0x0,%ah # position
63 shll %eax # * 2
64 xchgl %eax,%ecx # Swap char, offset
65 movw %ax,(%edi,%ecx,1) # Write attr:char
66 incl %edx # Bump cursor
67 cmpb $SCR_COL,%dl # Beyond row?
68 jb crt_putchr.3 # No
69crt_putchr.2: xorb %dl,%dl # Zero column
70 incb %dh # Bump row
71crt_putchr.3: cmpb $SCR_ROW,%dh # Beyond screen?
72 jb crt_putchr.4 # No
73 leal 2*SCR_COL(%edi),%esi # New top line
74 movw $(SCR_ROW-1)*SCR_COL/2,%cx # Words to move
75 rep # Scroll
76 movsl # screen
77 movb $' ',%al # Space
78 movb $SCR_COL,%cl # Columns to clear
79 rep # Clear
80 stosw # line
81 movb $SCR_ROW-1,%dh # Bottom line
82crt_putchr.4: movw %dx,(%ebx) # Update position
83 popa # Restore
84 ret # To caller