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|
;; settime.z
;;
;; Read date and time from xtrs 1.9 emulator trap and set
;; TRS-80 system date and time.
;;
;; Copyright (c) 1998 Ulrich Mueller
;;
;; This software may be copied, modified, and used for any
;; purpose without fee, provided that (1) the above copyright
;; notice is retained, and (2) modified versions are clearly
;; marked as having been modified, with the modifier's name and
;; the date included.
;;
;; Last modified on Fri May 19 00:38:41 PDT 2000 by mann
;; modified on Sun Feb 22 21:27:13 CET 1998 by ulm
;; Model I/III addresses
@exit equ 402dh
@abort equ 4030h
;; Model 1 and 3 store the last 2 digits of the year in the year byte
time1$ equ 4041h ; seconds/minutes/hours
date1$ equ 4044h ; year/day/month
time3$ equ 4217h
date3$ equ 421ah
;; Model 4 SVCs
@svc equ 40 ; rst address for SVCs
;@svc equ 5 ; older zmac requires 8080-style "rst 5"
@exit6 equ 22
@abort6 equ 21
;; Model 4 stores the offset from 1900 in the year byte
time4$ equ 002dh
date4$ equ 0033h
;; Emulator trap instructions
emt_time equ 36edh
org 5200h
settime:
call initj ; init OS-dependent tables
ld bc, 0ffffh
ld a, 1 ; get local time from Unix
defw emt_time ; BCDE: seconds since 1970
ld a, b
and c
inc a
jp z, abort
di
ld hl, (time)
ld a, 60
call divide
ld (hl), a ; seconds
inc hl
ld a, 60
call divide
ld (hl), a ; minutes
inc hl
ld a, 24
call divide
ld (hl), a ; hours
ex de, hl ; HL: days since 1970
ld bc, 19*256+70-1
ld de, 365
year1: inc c ; count years in C
ld a, c
sub 100
jr c, year2
ld c, a
inc b ; centuries
ld a, b
year2: and 3
sub 1
sbc hl, de
jr nc, year1
rlca
adc hl, de ; HL: days since 1 january
push hl
ld hl, (date)
call putyr ; year to (hl)
inc hl
ex (sp), hl
and 1 ; A=1 for leap year, 0 else
add a, 28
ld c, a
ld b, 0
ld d, b
month1: inc b ; count months in B
ld a, b
ld e, c
cp 2
jr z, month2 ; february
ld e, 31
and 9
jp po, month2 ; 31 days
dec e ; 30 days
month2: sbc hl, de ; subtract length of month
jr nc, month1
adc hl, de
ld c, l
pop hl
ld (hl), c ; day
inc hl
ld (hl), b ; month
ei
ld hl,0 ; needed on Model 4 --mann
jr exit
;; divide BCDE / A
;; returns quotient in BCDE, remainder in A
divide: push hl
neg
ld h, a
sub a
ld l, 33
div1: rla
add a, h
jr c, div2
sub h
div2: rl e
rl d
rl c
rl b
dec l
jr nz, div1
pop hl
ret
;; Jump tables for OS independence
;; Model 1
startj:
exit: jp @exit
abort: jp @abort
time: defw time1$
date: defw date1$
putyr: jp putyr1
endj:
;; Model 3
startj3:
jp @exit
jp @abort
defw time3$
defw date3$
jp putyr3
;; Model 4
startj4:
ld a, @exit6
rst @svc
ld a, @abort6
rst @svc
defw time4$
defw date4$
jp putyr4
;; Initialize tables
;; Changed to work even on a Model III (or Model 4 in III mode)
;; using MODELA/III as its ROM. Previous version didn't. --mann
;;
initj: ld hl, startj4 ; model 4?
ld a, (000ah)
cp 40h
jr nz, movej ; go if so
ld hl, startj3 ; model 3?
ld a, (0125h)
cp 'I'
ret nz ; return if not
movej: ld de, startj
ld bc, endj - startj
ldir
ret
;; Create year byte.
;; On entry, c has 2-digit year, b has century.
;; On exit, (hl) has year byte.
;; Model I/III, put 2-digit year
putyr1:
putyr3: ld (hl), c
ret
;; Model 4, put offset from 1900 (laboriously recomputed, sigh)
putyr4: push af
push bc
ld a, b
sub 19
ld b, a
ld a, c
jr z, py41
py40: add a, 100
djnz py40
py41: ld (hl), a
pop bc
pop af
ret
end settime
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