crt.s revision 329145
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: stable/11/stand/pc98/kgzldr/crt.s 200776 2009-12-21 14:59:23Z nyan $ 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