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_TEXT	segment	byte public 'CODE'
DGROUP	group	_DATA,_BSS
	assume	cs:_TEXT,ds:DGROUP,ss:DGROUP
_TEXT	ends

_DATA	segment word public 'DATA'
d@	label	byte
d@w	label	word
_DATA	ends

_BSS	segment word public 'BSS'
b@	label	byte
b@w	label	word
_BSS	ends

_TEXT	segment	byte public 'CODE'

	extrn	_mputchar:near

old_isr	dd	?

	public	_mscisr
_mscisr	proc	near
	cmp	ah,0eh
	je	do_local
	jmp	cs:[old_isr]
do_local:
	pusha
	push	es
	push	ds
	mov	cx, DGROUP
	mov	ds, cx
	mov	es, cx
	mov	ah,0
	push	ax
	call	_mputchar
	pop	ax
	pop	ds
	pop	es
	popa
	iret
_mscisr	endp

	public	_bell
_bell	proc	near
	mov ax,0e07h
	pushf
	call	cs:[old_isr]
	ret
_bell	endp

	public	_mscisr_init
_mscisr_init	proc	near
	push	es
	cli
	mov	ax,0
	mov	es,ax
	mov	bx,es:[40h]
	mov	word ptr cs:[old_isr], bx
	mov	ax,  offset _mscisr
	mov	word ptr es:[40h], ax
	mov	bx,es:[42h]
	mov	word ptr cs:[old_isr+2], bx
	mov	word ptr es:[42h], cs
	pop	es
	sti
	ret
_mscisr_init	endp

	public	_mscisr_uninit
_mscisr_uninit	proc	near
	push	es
	cli
	mov	ax,0
	mov	es,ax
	mov	bx, word ptr cs:[old_isr]
	mov	es:[40h], bx
	mov	bx, word ptr cs:[old_isr+2]
	mov	es:[42h], bx
	pop	es
	sti
	ret
_mscisr_uninit	endp

_TEXT	ends
	end