;+----------------------------------------------------------------------+
;| BZ8DCLK Read time and date from real-time-clock, convert to |
;| Z80dos format and exit with HL pointing to buffer. |
;| |
;| For MicroBee's with Z80DOS and BIOS V9 or PJB's BIOS. |
;| |
;| BZ8DCLK.Z80 adapted from Peter De Lacey's BIOSCLK.Z80. |
;| BIOSCLK.Z80 adapted from Ron Murray's BEECLK.Z80. |
;| BEECLK.Z80 adapted from S. Kluger's UNDATE.ASM. |
;| |
;| BZ8DCLK.Z80 written by Phil Summers c/o Z-node 62 Perth |
;+----------------------------------------------------------------------+
bz8dclk push de ; save all 1
push bc ; registers 1
push af ; used 1
ld hl,tb ; 3
push hl ; read time 1
ld e,0 ; and date from 2
ld b,7 ; RTC using 2
ld a,26 ; extended 2
rst 28h ; BIOS call 1
pop hl ; 1
ld b,3 ; 2
lp ld a,(hl) ; 1
ld e,a ; 1
and 0FH ; 2
ld d,a ; 1
ld a,e ; convert BCD 1
and 0F0H ; year, month 2
rrca ; and date in 1
ld e,a ; A to binary 1
rrca ; 1
rrca ; 1
add a,e ; 1
add a,d ; 1
ld (hl),a ; save binary 1
inc hl ; value and point 1
djnz lp ; to next 2
ld l,a ; count days in HL 1
ld h,b ; start with the date 1 b=0
ld de,365 ; days in a year, start 3
ld bc,78+(3*256) ; year, leap year mask 3
ay ld a,(year) ; exit if the year 3
cp c ; counter has reached 1
jr z,fin ; the current year 2
inc c ; add 365 days 1
add hl,de ; for each year 1
ld a,c ; also, if 1
and b ; the year is 1
jr nz,ay ; a leap year 2
inc hl ; then add an 1
jr ay ; extra day 2
fin and b ; if this year is 1
ld a,(month) ; a leap year but 3
jr nz,nly ; if the month isn't 2
cp b ; past February 1 b=3
jr nc,nly ; then subtract the 2
dec hl ; incorrect leap year 1
nly push hl ; save days so far 1
ld e,a ; calculate the 1
dec d ; address of the 1 d=0
ld hl,dt-1 ; number of days 3
add hl,de ; so far this 1
ld c,(hl) ; year and get 1
ld b,d ; it in BC 1
add a,246 ; adjust fo Oct., 2
rl b ; Nov. and Dec. 2
pop hl ; add year-days 1
add hl,bc ; to month-days 1
ld (nd),hl ; and save in buffer 3
pop af ; restore all 1
pop bc ; registers 1
pop de ; used 1
ld hl,nd ; exit with HL 3
ret ; pointing to buffer 1
dt db 0 ; 1st Jan - 1st Jan 1
db 31 ; 1st Jan - 1st Feb 1
db 59 ; 1st Jan - 1st Mar 1
db 90 ; 1st Jan - 1st Apr 1
db 120 ; 1st Jan - 1st May 1
db 151 ; 1st Jan - 1st Jun 1
db 181 ; 1st Jan - 1st Jul 1
db 212 ; 1st Jan - 1st Aug 1
db 243 ; 1st Jan - 1st Sep 1
db 273-256 ; 1st Jan - 1st Oct 1
db 304-256 ; 1st Jan - 1st Nov 1
db 334-256 ; 1st Jan - 1st Dec 1
tb equ $
year ds 1 ; year 1
month ds 1 ; month 1
nd ds 1 ; date 1
ds 1 ; day 1
ds 1 ; hours 1
ds 1 ; minutes 1
ds 1 ; seconds 1
