;
; ARKDATE - support for Time and Date stamping
;
; 4/18/89 -- Written for Z80DOS file-modify stamps
;
;
; The user should use the area starting at Z80Date
	.z80
	aseg			; keep M80 happy....
	org	103h

yr:	DB	88		; [103h]
mo:	DB	4		; [104h]
day:	DB	14		; [105h]
hour:	db	0		; [106h]
min:	db	0		; [107h]

TDate_:	jp	Signon		; Today's-Date (called at init-time)           [108h]
FDate_:	jp	Z80Date		; File-Date (called immediately after F_OPEN)  [10Bh]
CDate_: ds	3		; convert and save date (don't overwrite this) [10Eh]
Puts_:	ds	3		; handy output routine

Signon:	ld	hl,Version
	call	Puts_
	ret

Version:
	db	'Z80DOS Version',10,0

;  Get Z80-DOS date, convert to YYMMDDHHMM and save at 0103h -- DO NOT
;  ALTER BC, IX, or IY
Z80Date:push	ix
	push	iy
	push	bc
	ld	c,54		; Z80Dos Get-Stamp
	call	5
	ld	de,mo
	inc	hl		; skip over creation date
	inc	hl		;   and we point to Last Modify
	ld	bc,4		; only care about the next 4 (no seconds)
	ldir			; and move for easier access

	ld	hl,(mo)
;
; DATEHL converts the value in HL to BCD year, month, day
;	 for use with Z80DOS time stamps.
;
; Inputs:	HL contains hex days since December 31, 1977
;
; Outputs:	H contains BCD 20th century year
;		L contains BCD month
;		A contains BCD day
;
;		Zero flag set (Z) and A=0 if invalid date (zero) detected,
;		Zero flag reset (NZ) and A=0ffh otherwise.

; Converted to 8080 from DATEHL by Carson Wilson who Adapted from B5C-CPM3.INS

DateHL:
	LD	A,H
	OR	L		; Test blank date (zero)
	jp	Z,nodate	; make date = 00/00/00 00:00
	LD	(DAYS),HL	; Save initial value
	LD	B,78		; Set years counter
loop:
	call	ckleap
	LD	DE,-365		; Set up for subtract
	jr	NZ,NOLPY	; Skip if no leap year
	DEC	DE		; Set for leap year
nolpy:
	ADD	HL,DE		; Subtract
	jr	NC,YDONE	; Continue if years done
	LD	A,H
	OR	L
	jr	Z,YDONE
	LD	(DAYS),HL	; Else save days count
	INC	B		; Increment years count
	jr	LOOP		; And do again
;
; The years are now finished, the years count is in 'B' (HL is invalid)
;
ydone:
	LD	A,B
	LD	(yr),A		; save year
;
	call	ckleap		; Check if leap year
	LD	A,-28
	JP	NZ,FEBNO	; February not 29 days
	LD	A,-29		; Leap year
febno:
	LD	(FEB),A		; Set february
	LD	HL,(DAYS)	; Get days count
	LD	DE,MTABLE	; Point to months table
	LD	B,0FFH		; Set up 'B' for subtract
	LD	A,0		; Set a for # of months
mloop:
	PUSH	AF
	LD	A,(DE)		; Get month
	LD	C,A		; Put in 'C' for subtract
	POP	AF
	LD	(DAYS),HL	; save days count
	ADD	HL,BC		; Subtract
	INC	DE		; Increment months counter
	INC	A
	jr	C,MLOOP		; Loop for next month

;
; The months are finished, days count is on stack.  First, calculate
; month.
;
mdone:
	LD	B,A		; Save months
	LD	HL,(DAYS)
	LD	A,H
	OR	L
	jr	NZ,NZD
	DEC	DE
	DEC	DE
	LD	A,(DE)
	CPL
	INC	A
	LD	L,A
	DEC	B
nzd:
	LD	A,L		; Retrieve binary day of month
	ld	(day),a
;
	LD	A,B		; Retrieve the binary month
	ld	(mo),a
;
	OR	A		; Set NZ flag

jtoc4:	ld	a,(hour)	; Z80DOS (and DRI) want the time as BCD --
	call	bcd2bin		;  better convert it to binary for ARK
	ld	(hour),a
	ld	a,(min)
	call	bcd2bin
	ld	(min),a
nodate:	pop	bc
	pop	iy
	pop	ix
	call	CDate_		; make it readable to ARK
	ret


bcd2bin: ld	d,a
	and	0fh		; E = the 1's digit
	ld	e,a
	ld	a,d		; get back our BCD number
	and	0f0h		; mask off ones for just the 10's
	rrca
	rrca
	rrca
	rrca			; and put in LS bits
	ld	d,a		; save a copy for multiplying back
	add	a,a		;  times 2
	add	a,a		;    "   4
	add	a,a		;  times 8
	add	a,d		;  times 9
	add	a,d		;  times 10
	add	a,e		; add in ones
	ret			; and we're done!


;
; Support Routines:
;

;
; Check for leap years.
;
ckleap:
	LD	A,B
	AND	0FCH
	CP	B
	ret


mtable:
	db	-31		;January
feb:	db	-28		;February
	db	-31,-30,-31,-30	;Mar-Jun
	db	-31,-31,-30	;Jul-Sep
	db	-31,-30,-31	;Oct-Dec

days:	dw	0		; temp storage

	end