2 # Copyright (c) 1999 Global Technology Associates, Inc.
5 # Redistribution and use in source and binary forms, with or without
6 # modification, are permitted provided that the following conditions
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.
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.
26 # From: btx.s 1.10 1999/02/25 16:27:41 rnordier
30 # Screen defaults and assumptions.
32 .set SCR_MAT,0xe1 # Mode/attribute
33 .set SCR_COL,0x50 # Columns per row
34 .set SCR_ROW,0x19 # Rows per screen
36 # BIOS Data Area locations.
38 .set BDA_POS,0x53e # Cursor position
42 # void crt_putchr(int c)
44 crt_putchr: movb 0x4(%esp,1),%al # Get character
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
51 crt_putchr.1: cmpb $0xa,%al # New line?
54 movb %al,(%edi,%ecx,1) # Write char
56 movb %ah,(%edi,%ecx,1) # Write attr
59 crt_putchr.2: movw %dx,%ax
65 crt_putchr.3: cmpw $SCR_ROW*SCR_COL*2,%dx
67 leal 2*SCR_COL(%edi),%esi # New top line
68 movw $(SCR_ROW-1)*SCR_COL/2,%cx # Words to move
73 movb $SCR_COL,%cl # Columns to clear
76 movw $(SCR_ROW-1)*SCR_COL*2,%dx
77 crt_putchr.4: movw %dx,(%ebx) # Update position
79 crt_putchr.5: inb $0x60,%al # Move cursor