title	'Time module for the Modular CP/M 3 BIOS'

	public	?time, gs_rtc
	public	prt0ini
	public	gtimer,gstimer

	extrn	@date,@hour,@min,@sec
	extrn	f_cpu
	extrn	ioiniml,div32_16
	extrn	msg.sm,msg.recv
	extrn	_b0call

	include config.inc
	include	z180reg.inc


;----------------------------------------------------------------------
; c == 00h: get time
; c == ffh: set time

	cseg	; time must be done from resident memory
?time:
	inc	c			;zero if ff
	ld	c,3
	jr	z,time_set

	ld	a,(time_to)
	or	a
	ret	nz

	dec	c
time_set:
	b0call	gs_rtc
	ld	a,0ffh
	ld	(time_to),a
	ret

;----------------------------------------------------------------------
; c = 2: get time
; c = 3: set time

	dseg
gs_rtc:

	push	hl
	push	de

	ld	hl,(@date)
	ld	a,(@hour)
	ld	d,a
	ld	a,(@min)
	ld	e,a
	ld	a,(@sec)
	ld	b,a			;b = sec, c = subcommand
	push	hl			;2
	push	de			;4
	push	bc			;6
	ld	hl,3 * 256 + 0		;h = command, l = 0
	push	hl			;8

	ld	h,l			;hl = 0
	add	hl,sp
	push	hl
	inc	hl			;7

	ld	b,7
	call	msg.sm

	pop	hl			;8
	ld	b,8			; max receive message len
	call	msg.recv

	pop	hl			;len/command (discard)
	pop	bc			;subc/sec
	pop	de
	pop	hl
	ld	a,b
	ld	(@sec),a
	ld	a,e
	ld	(@min),a
	ld	a,d
	ld	(@hour),a
	ld	(@date),hl

	pop	de
	pop	hl
	ret

;----------------------------------------------------------------------

;uint32_t get_timer(uint32_t base)
;{
;	uint32_t ret;
;	ATOMIC_BLOCK(ATOMIC_FORCEON)
;	{
;		ret = timestamp;
;	}
;	return ret - base;
;}

	dseg	; called from banked only
gstimer:
	push	de
	ex	de,hl
	ld	hl,(uptime)
	or	a
	sbc	hl,de
	pop	de
	ret

;----------------------------------------------------------------------

gtimer:
	push	bc
	ld	b,h
	ld	c,l
	or	a
	di
	ld	hl,(uptime)
	sbc	hl,bc
	push	hl
	ei
	ld	hl,(uptime+2)
	sbc	hl,de
	ex	de,hl
	pop	hl
	pop	bc
	ret

;----------------------------------------------------------------------
; intit timer interrupt

	dseg

prt0ini:
	in0	a,(tcr)
	push	af
	and	~(M_TIE0+M_TDE0)	;stop timer 0
	out0	(tcr),a

	ld	a,i
	ld	h,a
	in0	a,(il)
	and	0E0h
	or	IV$PRT0
	ld	l,a
	ld	de,isvprt0
	ld	(hl),e
	inc	hl
	ld	(hl),d

	ld	hl,(f_cpu)
	ld	de,(f_cpu+2)
	ld	bc,PRT_PRE * 800	;1/800 s == 1,25 ms interrupt rate
	call	div32_16

	out0	(tmdr0l),l
	out0	(tmdr0h),h
	out0	(rldr0l),l
	out0	(rldr0h),h
	pop	af
	or	(M_TIE0+M_TDE0)
	out0	(tcr),a
	ret


;----------------------------------------------------------------------
; timer interrupt
;
;    1,25 ms clock tick


	cseg	;common!
isvprt0:
	push	af
	in0	a,(tcr)			;reset TIF0 flag
	in0	a,(tmdr0l)
	in0	a,(tmdr0h)

	push	hl			;11
	ld	hl,uptime		; 9
	inc	(hl)			;10
	jr	nz,iprt_1		;6/8	38
	inc	hl       		; 4
	inc	(hl)			;10
	jr	nz,iprt_1		;6/8		58
	inc	hl			; 4
	inc	(hl)			;10
	jr	nz,iprt_1		;6/8
	inc	hl			; 4
	inc	(hl)			;10
iprt_1:
	pop	hl			; 9
	ld	a,(time_to)
	sub	a,1
	jr	c,iprt_0
	ld	(time_to),a
iprt_0:
	pop	af
	ei
	ret

uptime:
	dw	0,0
time_to:
	db	0

	end