257 lines
8.1 KiB
NASM
257 lines
8.1 KiB
NASM
;
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; File:
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; console.asm
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; Description:
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; Console device driver
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;
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; Copyright (c) 1998
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; Pasquale J. Villani
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; All Rights Reserved
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;
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; This file is part of DOS-C.
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;
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; DOS-C is free software; you can redistribute it and/or
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; modify it under the terms of the GNU General Public License
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; as published by the Free Software Foundation; either version
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; 2, or (at your option) any later version.
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;
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; DOS-C is distributed in the hope that it will be useful, but
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; WITHOUT ANY WARRANTY; without even the implied warranty of
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; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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; the GNU General Public License for more details.
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;
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; You should have received a copy of the GNU General Public
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; License along with DOS-C; see the file COPYING. If not,
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; write to the Free Software Foundation, 675 Mass Ave,
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; Cambridge, MA 02139, USA.
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;
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; $Header$
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;
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%include "io.inc"
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segment _IO_FIXED_DATA
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global ConTable
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ConTable db 0Ah
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dw ConInit
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dw _IOExit
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dw _IOExit
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dw _IOCommandError
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dw ConRead
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dw CommonNdRdExit
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dw CommonNdRdExit
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dw ConInpFlush
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dw ConWrite
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dw ConWrite
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dw _IOExit
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CTL_PRT_SCREEN equ 7200h
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CTL_P equ 10h
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segment _LOWTEXT
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uScanCode db 0 ; Scan code for con: device
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global _kbdType
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_kbdType db 0 ; 00 for 84key, 10h for 102key
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global ConInit
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ConInit:
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xor ax,ax
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mov ds,ax
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mov al,[496h]
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and al,10h
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mov byte[cs:_kbdType],al ; enhanced keyboard if bit 4 set
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jmp _IOExit
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;
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; Name:
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; ConRead
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;
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; Function:
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; Read to address in es:di characters from the keyboard. Cx contains
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; a count of how many characters are to be transferred.
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;
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; Description:
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; Calls KbdRdChar to read the characters. Destroys ax.
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;
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global ConRead
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ConRead:
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jcxz ConRead2 ; Exit if read of zero
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ConRead1:
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call KbdRdChar ; Get a char from kbd in al
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stosb ; Store al to es:[di]
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loop ConRead1 ; Loop until all are read
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ConRead2:
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jmp _IOExit
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readkey:
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mov ah,[cs:_kbdType]
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int 16h
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checke0: cmp al,0xe0 ; must check for 0xe0 scan code
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jne .ret
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or ah,ah ; check for Greek alpha
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jz .ret
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mov al,0 ; otherwise destroy the 0xe0
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.ret: retn
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;
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; Name:
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; KbdRdChar
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;
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; Function:
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; Read a character from the keyboard.
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;
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; Description:
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; This subroutine reads a character from the keyboard. It also handles
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; a couple of special functions.
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; It converts ctrl-printscreen to a control-P.
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; It also accounts for extended scan codes by saving off
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; the high byte of the return and returning it if it was non-zero on
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; the previous read.
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;
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global KbdRdChar
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KbdRdChar:
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xor ax,ax ; Zero the scratch register
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xchg [cs:uScanCode],al ; and swap with scan code
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; now AL is set if previous key was extended,
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; and previous is erased in any case
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or al,al ; Test to see if it was set
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jnz KbdRdRtn ; Exit if it was, returning it
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call readkey ; get keybd char in al, ah=scan
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or ax,ax ; Zero ?
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jz KbdRdChar ; Loop if it is
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cmp ax,CTL_PRT_SCREEN ; Ctrl-Print screen?
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jne KbdRd1 ; Nope, keep going
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mov al,CTL_P ; Yep, make it ^P
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KbdRd1:
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or al,al ; Extended key?
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jnz KbdRdRtn ; Nope, just exit
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mov [cs:uScanCode],ah ; Yep, save the scan code
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KbdRdRtn:
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retn
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;
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; Name:
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; CommonNdRdExit
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;
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; Function:
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; Checks the keyboard input buffer.
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;
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; Description:
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; Calls int 16 (get status). Sets Busy-Flag in status field. Destroys ax.
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;
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global CommonNdRdExit
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CommonNdRdExit: ; *** tell if key waiting and return its ASCII if yes
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mov al,[cs:uScanCode] ; Test for last scan code
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; now AL is set if previous key was extended,
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or al,al ; Was it zero ?
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jnz ConNdRd2 ; Jump if there's a char waiting
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mov ah,1
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add ah,[cs:_kbdType]
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int 16h ; Get status, if zf=0 al=char
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jz ConNdRd4 ; Jump if no char available
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or ax,ax ; Also check for ax=0 as apparently some
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jz ConNdRd4 ; int16h handlers set ax=0 to indicate unsupported function
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call checke0 ; check for e0 scancode
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or ax,ax ; Zero ?
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jnz ConNdRd1 ; Jump if not zero
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call readkey
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jmp short CommonNdRdExit
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; if char was there but 0, fetch and retry...
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; (why do we check uScanCode here?)
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ConNdRd1:
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cmp ax,CTL_PRT_SCREEN ; Was ctl+prntscrn key pressed?
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jne ConNdRd2 ; Jump if not
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mov al,CTL_P
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ConNdRd2:
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lds bx,[cs:_ReqPktPtr] ; Set the status
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cmp byte[bx+2],6 ; input status call?
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je ConNdRd3
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mov [bx+0Dh],al ; return the ASCII of that key
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ConNdRd3:
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jmp _IOExit
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ConNdRd4:
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jmp _IODone
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global ConInpFlush
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ConInpFlush: ; *** flush that keyboard queue
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call KbdInpChar ; get all available keys
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jmp _IOExit ; do not even remember the last one
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KbdInpChar: ; *** get ??00 or the last waiting key after flushing the queue
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xor ax,ax
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mov byte [cs:uScanCode],al
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KbdInpCh1:
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mov ah,1
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add ah,[cs:_kbdType]
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int 16h ; get status, if zf=0 al=char
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jz KbdInpRtnZero ; Jump if zero
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; returns 0 or the last key that was waiting in AL
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call readkey
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jmp short KbdInpCh1
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; just read any key that is waiting, then check if
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; more keys are waiting. if not, return AL of this
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; key (which is its ASCII). AH (scan) discarded!
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KbdInpRtnZero: mov ah,1 ; if anybody wants "1 if no key was waiting"!
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KbdInpRtn:
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retn
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global ConWrite
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ConWrite:
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jcxz ConNdRd3 ; Exit if nothing to write
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ConWr1:
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mov al,[es:di]
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inc di
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int 29h ; Do fast output call
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loop ConWr1 ; Loop if more to output
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jmp _IOExit
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CBreak:
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mov byte [cs:uScanCode],3 ; Put a ^C into the buffer
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IntRetn:
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iret
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; global _cso
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;_cso
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; push bp
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; mov bp,sp
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; push ax
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; mov ax,[bp+4]
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; int 29h
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; pop ax
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; pop bp
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; retn
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global _int29_handler
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_int29_handler:
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push ax
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push si
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push di
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push bp
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push bx
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mov ah,0Eh
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mov bx,7
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int 10h ; write char al, teletype mode
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pop bx
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pop bp
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pop di
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pop si
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pop ax
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iret
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