Changeset View
Changeset View
Standalone View
Standalone View
head/stand/i386/kgzldr/crt.S
Property | Old Value | New Value |
---|---|---|
svn:keywords | null | FreeBSD=%H \ No newline at end of property |
# | |||||
# 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: btx.s 1.10 1999/02/25 16:27:41 rnordier | |||||
# $FreeBSD$ | |||||
# | |||||
# Screen defaults and assumptions. | |||||
.set SCR_MAT,0x7 # Mode/attribute | |||||
.set SCR_COL,0x50 # Columns per row | |||||
.set SCR_ROW,0x19 # Rows per screen | |||||
# BIOS Data Area locations. | |||||
.set BDA_SCR,0x449 # Video mode | |||||
.set BDA_POS,0x450 # Cursor position | |||||
.globl crt_putchr | |||||
# void crt_putchr(int c) | |||||
crt_putchr: movb 0x4(%esp,1),%al # Get character | |||||
pusha # Save | |||||
xorl %ecx,%ecx # Zero for loops | |||||
movb $SCR_MAT,%ah # Mode/attribute | |||||
movl $BDA_POS,%ebx # BDA pointer | |||||
movw (%ebx),%dx # Cursor position | |||||
movl $0xb8000,%edi # Regen buffer (color) | |||||
cmpb %ah,BDA_SCR-BDA_POS(%ebx) # Mono mode? | |||||
jne crt_putchr.1 # No | |||||
xorw %di,%di # Regen buffer (mono) | |||||
crt_putchr.1: cmpb $0xa,%al # New line? | |||||
je crt_putchr.2 # Yes | |||||
xchgl %eax,%ecx # Save char | |||||
movb $SCR_COL,%al # Columns per row | |||||
mulb %dh # * row position | |||||
addb %dl,%al # + column | |||||
adcb $0x0,%ah # position | |||||
shll %eax # * 2 | |||||
xchgl %eax,%ecx # Swap char, offset | |||||
movw %ax,(%edi,%ecx,1) # Write attr:char | |||||
incl %edx # Bump cursor | |||||
cmpb $SCR_COL,%dl # Beyond row? | |||||
jb crt_putchr.3 # No | |||||
crt_putchr.2: xorb %dl,%dl # Zero column | |||||
incb %dh # Bump row | |||||
crt_putchr.3: cmpb $SCR_ROW,%dh # Beyond screen? | |||||
jb crt_putchr.4 # No | |||||
leal 2*SCR_COL(%edi),%esi # New top line | |||||
movw $(SCR_ROW-1)*SCR_COL/2,%cx # Words to move | |||||
rep # Scroll | |||||
movsl # screen | |||||
movb $' ',%al # Space | |||||
movb $SCR_COL,%cl # Columns to clear | |||||
rep # Clear | |||||
stosw # line | |||||
movb $SCR_ROW-1,%dh # Bottom line | |||||
crt_putchr.4: movw %dx,(%ebx) # Update position | |||||
popa # Restore | |||||
ret # To caller |