80 lines
2.6 KiB
ArmAsm
80 lines
2.6 KiB
ArmAsm
#
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# Copyright (c) 1999 Global Technology Associates, Inc.
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
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# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
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# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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# OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#
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# From: btx.s 1.10 1999/02/25 16:27:41 rnordier
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# $FreeBSD$
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#
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# Screen defaults and assumptions.
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.set SCR_MAT,0xe1 # Mode/attribute
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.set SCR_COL,0x50 # Columns per row
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.set SCR_ROW,0x19 # Rows per screen
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# BIOS Data Area locations.
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.set BDA_POS,0x53e # Cursor position
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.globl crt_putchr
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# void crt_putchr(int c)
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crt_putchr: movb 0x4(%esp,1),%al # Get character
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pusha # Save
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xorl %ecx,%ecx # Zero for loops
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movb $SCR_MAT,%ah # Mode/attribute
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movl $BDA_POS,%ebx # BDA pointer
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movw (%ebx),%dx # Cursor position
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movl $0xa0000,%edi
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crt_putchr.1: cmpb $0xa,%al # New line?
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je crt_putchr.2 # Yes
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movw %dx,%cx
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movb %al,(%edi,%ecx,1) # Write char
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addl $0x2000,%ecx
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movb %ah,(%edi,%ecx,1) # Write attr
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addw $0x02,%dx
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jmp crt_putchr.3
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crt_putchr.2: movw %dx,%ax
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movb $SCR_COL*2,%dl
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div %dl
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incb %al
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mul %dl
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movw %ax,%dx
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crt_putchr.3: cmpw $SCR_ROW*SCR_COL*2,%dx
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jb crt_putchr.4 # No
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leal 2*SCR_COL(%edi),%esi # New top line
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movw $(SCR_ROW-1)*SCR_COL/2,%cx # Words to move
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rep # Scroll
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movsl # screen
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movb $' ',%al # Space
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xorb %ah,%ah
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movb $SCR_COL,%cl # Columns to clear
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rep # Clear
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stosw # line
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movw $(SCR_ROW-1)*SCR_COL*2,%dx
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crt_putchr.4: movw %dx,(%ebx) # Update position
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popa # Restore
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ret # To caller
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