; MXC-DS10.ASM DateStamper Overlay rev 1.0
;
; MEXplus Clock Overlay for Plu*Perfect's DateStamper(tm)
;
; Usage: any Z80 computer using DateStamper (version after 6/85)
; Otherwise, this code is HARDWARE INDEPENDENT as it gets
; date via DateStamper rather than directly from clock.
;
;------------------------------------------------------------------------
; revision | date | description | author
;----------+-------------------------------------------------------------
; 1.0 | 8Mar87 | created original, some code from | Jim Lill
; | | MXC-MC10.ASM, DATE.ASM, HSHBGPAT.Z80 |
;------------------------------------------------------------------------
bdos equ 0005h
cent equ 1900 ;DS doesn't supply century, change this
;in a few years!
;...............................
;
; Prtval macro prints text and value during assembly
;
prtval macro msg,n
.printx msg n
endm
;...............................
;
; start of MEX stuff....
org 0100h
db 0C3h ; this is for 8080 processor
;...............................
;
; JMP table for clock overlay
;
org 0E00h ;start of clock overlay
start: jp gettim ;get time
jp getdat ;get date
ret ;cset processor
nop
nop
ret ;clock overlay init
nop
nop
ret ;clock overlay de-init
nop
nop
;...............................
;
; gettim, this routine gets the time in clktbl and readies it for MEX
;
; B - hours (0-23)
; C - minutes (0-59)
; D - seconds (0-59)
; E - hundredths of sec (0-99)
;
gettim:
call dschk ; see if DS is running
jr z,cont1 ; jump to cont1 if it is
ld DE,0 ; \__ make things zero if not
ld BC,0 ; /
ret ; report back to MEX
cont1: call putdat ; get date and put BCD data in CLKTBL
ld A,(hrs) ; load packed BCD hours into A
call bcd2bin ; \__ place bin hours in B
ld B,A ; /
ld A,(mins) ; load packed BCD mins into A
call bcd2bin ; \__ place bin mins in C
ld C,A ; /
ld A,(secs) ; loaded packed BCD secs into A
call bcd2bin ; \__ place bin secs in D
ld D,A ; /
ld E,0 ; we don't have sec/100, so zero
ret ; back to MEX
;................................
;
; getdat, this routine gets the date in clktbl and readies it for MEX
;
; BC - year (1985-2099)
; D - month (1=jan, 2=feb, etc)
; E - day of month (1-31)
;
getdat:
call dschk ; see if DS is running
jr z,cont2 ; jump to cont2 if it is
ld E,1 ; if not make day 1 ----\ Legal
ld D,1 ; " " " month 1 + Values
ld BC,1999 ; " " " year 1999 --/ for MEX
ret ; report back to MEX
cont2: call putdat ; get date and put BCD data in CLKTBL
;
ld A,(day) ; load packed BCD day into A
call bcd2bin ; \__ place bin day in E
ld E,A ; /
ld A,(mon) ; load packed BCD mon into A
call bcd2bin ; \__ place bin mon in D
ld D,A ; /
ld A,(year) ; load packed BCD year (00-99) into A
call bcd2bin ; \__ place bin year in C
ld C,A ; /
ld B,0 ; make a whole year value
ld HL,cent ; by adding cent (eg 1900)
add HL,BC ; to partial year
ld C,L ; move answer into BC
ld B,H ; " " " "
ret ; back to MEX
;...............................
;
; bcd2bin --> packed BCD (A) converted to Binary (A)
;
bcd2bin:
push BC ; be safe
ld C,A ; load in value from A
and 0F0h ; mask off lower nibble
rra ; \
rra ; \_/ move upper nibble
rra ; / \ into lower nibble
rra ; /
ld B,A ; store value *1
add A ; \__ *4
add A ; /
add B ; now *5
add A ; finally *10
ld B,A ; store 10's digit in B
ld A,C ; \__ load lower digit into A
and 00Fh ; /
add B ; combine both digs. into single byte
pop BC ; restore register
ret ;
;...............................
;
; Check for DateStamper running and set up code for getting time string.
; The routine returns Z if DS is running and NZ if not.
dschk:
ld e,'D' ; DateStamper ID character
ld c,0ch ; Return version function
call bdos
cp 22h ; Must be CP/M 2.2
ret nz ; If not, return NZ
ld a,h ; Check for return of ID
cp 'D'
ret nz ; If not, return NZ
ex de,hl ; Get time subroutine addr into HL
ld (time),hl ; Modify code in next routine
ret ; Return Z showing success
;................................
; Get the time string from DateStamper and put it in CLKTBL
