ALIGN 4
_olddostimer dd	?
timerspeed dw	0
timercount dw	0

vidtimer PROC FAR
	push	ax
	push	cx
	push	dx
	push	ds
	IF 0
	mov	dx,3dah
	in	al,dx
	mov	dx,3c0h
	mov	al,11h+20h
	out	dx,al
	mov	al,4
	out	dx,al
	mov	cx,1000
@@pp:	loop	@@pp
	mov	dx,3dah
	in	al,dx
	mov	dx,3c0h
	mov	al,11h+20h
	out	dx,al
	mov	al,0
	out	dx,al
	ENDIF
	inc	cs:framecounter
	pop	ds
	pop	dx
	pop	cx
	mov	ax,cs:timerspeed
	add	cs:timercount,ax
	jnc	@@x
	pop	ax
	jmp	cs:_olddostimer
@@x:	mov	al,20h
	out	20h,al
	pop	ax
	iret
vidtimer ENDP

;北北北北 _vid_inittimer() 北北北北
;entry:	-
; exit: -
;descr: Captures the system timer and sets it to 70hz
_vid_inittimer PROC FAR
	CBEG
	xor	ax,ax
	mov	es,ax
	mov	eax,es:[8h*4+0]
	mov	cs:_olddostimer,eax
	cli
	mov	word ptr es:[8h*4+0],OFFSET vidtimer
	mov	es:[8h*4+2],cs
	mov	al,36h
	out	43h,al
	mov	ax,119318/7
	mov	cs:timerspeed,ax
	out	40h,al
	mov	al,ah
	out	40h,al
	sti
	CEND
_vid_inittimer ENDP

;北北北北 _vid_deinittimer() 北北北北
;entry:	-
; exit: -
;descr: Restores the system timer to its original state
_vid_deinittimer PROC FAR
	CBEG
	xor	ax,ax
	mov	es,ax
	cli
	mov	eax,cs:_olddostimer
	mov	es:[8h*4+0],eax
	mov	al,36h
	out	43h,al
	mov	ax,0
	out	40h,al
	mov	al,ah
	out	40h,al
	sti
	CEND
_vid_deinittimer ENDP