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; SCCSID = @(#)readclock.asm 1.2 85/07/25
;************************************************************************
;
; read_real_date reads real-time clock for date and returns the number
; of days elapsed since 1-1-80 in si
;
read_real_date: ;mjb002
assume ds:code,es:nothing
PUSH AX
PUSH CX
PUSH DX
XOR AH,AH ; throw away clock roll over ;3.30*
INT 1AH ;3.30*
POP DX
POP CX
POP AX
PUSH AX
PUSH BX
PUSH CX
PUSH DX
MOV CS:DAYCNT2,1 ;MJB002 REAL TIME CLOCK ERROR FLAG (+1 DA;3.30Y)
mov ah,4 ;mjb002 read date function code ;3.30*
int 1ah ;mjb002 read real-time clock ;3.30*
jnc read_ok ;mjb002 jmp success
jmp r_d_ret ;mjb002 jmp error
read_ok: ;mjb002 ******* get bcd values in binary *****
mov byte ptr bin_date_time+0,ch ;mjb002 store as hex value
mov byte ptr bin_date_time+1,cl ;mjb002 ...
mov byte ptr bin_date_time+2,dh ;mjb002 ...
mov byte ptr bin_date_time+3,dl ;mjb002 ...
MOV CS:DAYCNT2,2 ;MJB002 READ OF R-T CLOCK SUCCESSFUL ;3.30
call bcd_verify ;mjb002 verify bcd values in range
jc r_d_ret ;mjb002 jmp some value out of range
MOV CS:DAYCNT2,3 ;MJB002 READ OF R-T CLOCK SUCCESSFUL ;3.30
call date_verify ;mjb002 verify date values in range
jc r_d_ret ;mjb002 jmp some value out of range
MOV CS:DAYCNT2,0 ;MJB002 VERIFY SUCCESSFUL ;3.30;3.30
call in_bin ;mjb002 convert date to binary
;mjb002 ******* years since 1-1-80 *********
mov al,byte ptr bin_date_time+1 ;mjb002 get years into century
cbw ;mjb002
cmp byte ptr bin_date_time+0,20 ;mjb002 20th century?
jnz century_19 ;mjb002 jmp no
add ax,100 ;mjb002 add in a century
century_19: ;mjb002
sub ax,80 ;mjb002 subtract off 1-1-80
mov cl,4 ;mjb002 leap year every 4
div cl ;mjb002 al= # leap year blocks, ah= remainder
mov bl,ah ;mjb002 save odd years
cbw ;mjb002 zero ah
mov cx,366+3*365 ;mjb002 # of days in leap year blocks
mul cx ;mjb002 dx:ax is result
MOV CS:DAYCNT2,AX ;MJB002 SAVE COUNT OF DAYS ;3.30
mov al,bl ;mjb002 get odd years count
cbw ;mjb002
or ax,ax ;mjb002 is ax= 0?
jz leap_year ;mjb002 jmp if none
mov cx,365 ;mjb002 days in year
mul cx ;mjb002 dx:ax is result
ADD CS:DAYCNT2,AX ;MJB002 ADD ON DAYS IN ODD YEARS ;3.30
jmp short leap_adjustment ;mjb002 account for leap year
leap_year: ;mjb002 possibly account for a leap day
cmp byte ptr bin_date_time+2,2 ;mjb002 is month february
jbe no_leap_adjustment ;mjb002 jan or feb. no leap day yet.
leap_adjustment: ;mjb002 account for leap day
INC CS:DAYCNT2 ;MJB002 ... ;3.30
no_leap_adjustment: ;mjb002 ******* get days of month *******
mov cl,byte ptr bin_date_time+3 ;mjb002 ...
xor ch,ch ;mjb002
dec cx ;mjb002 because of offset from day 1, not day 0
ADD CS:DAYCNT2,CX ;MJB002 ******* GET DAYS IN MONTHS PRECEE;3.30DING *****
mov cl,byte ptr bin_date_time+2 ;mjb002 get month
xor ch,ch ;mjb002
dec cx ;mjb002 january starts at offset 0
shl cx,1 ;mjb002 word offset
mov si,offset month_table ;mjb002 beginning of month_table
add si,cx ;mjb002 point into month table
mov ax,word ptr [si];mjb002 get # days in previous months
ADD CS:DAYCNT2,AX ;MJB002 ... ;3.30
r_d_ret: ;mjb002
MOV SI,CS:DAYCNT2 ;MJB002 RESULT IN SI ;3.30
POP DX
POP CX
POP BX
POP AX
ret ;mjb002
r_t_retj:
xor cx,cx
xor dx,dx
jmp r_t_ret
;
; Read_Real_Time reads the time from the RTC. on exit, it has the number of
; ticks (at 18.2 ticks per sec.) in CX:DX.
;
Read_Real_Time:
mov ah,2 ;3.30*
int 1AH ;3.30*
jc r_t_retj
oktime:
mov byte ptr bin_date_time,ch ; hours
mov byte ptr bin_date_time+1,cl ; minutes
mov byte ptr bin_date_time+2,dh ; seconds
mov byte ptr bin_date_time+3,0 ; unused for time
call bcd_verify
jc r_t_retj
call time_verify
jc r_t_retj
call in_bin
MOV ch,byte ptr bin_date_time
MOV cl,byte ptr bin_date_time+1
MOV dh,byte PTR bin_date_time+2
MOV dl,byte PTR bin_date_time+3
message ftestinit,<"Read Time ">
mnum ftestinit,cx
message ftestinit,<" ">
mnum ftestinit,dx
message ftestinit,<cr,lf>
; get time in ticks in CX:DX
CALL word ptr cs:TimeToTicks ;3.30
message ftestinit,<"Conv Time ">
mnum ftestinit,cx
message ftestinit,<" ">
mnum ftestinit,dx
message ftestinit,<cr,lf>
r_t_ret:
ret
;
; in_bin converts bin_date_time values from bcd to bin
;
in_bin: ;mjb002
assume ds:code,es:nothing
mov al,byte ptr bin_date_time+0 ; century or hours
call bcd_to_bin ; ...
mov byte ptr bin_date_time+0,al ;
mov al,byte ptr bin_date_time+1 ; years or minutes
call bcd_to_bin ; ...
mov byte ptr bin_date_time+1,al ;
mov al,byte ptr bin_date_time+2 ; months or seconds
call bcd_to_bin ; ...
mov byte ptr bin_date_time+2,al ;
mov al,byte ptr bin_date_time+3 ; days (not used for time)
call bcd_to_bin ; ...
mov byte ptr bin_date_time+3,al ;
ret ;
;
; bcd_to_bin converts two bcd nibbles in al (value <= 99.) to
; a binary representation in al
; ah is destroyed
;
bcd_to_bin: ;mjb002
assume ds:nothing,es:nothing
mov ah,al ;mjb002 copy bcd number to ah
and ax,0f00fh ;mjb002 clear unwanted nibbles
mov bl,al ;mjb002 save units place
xchg ah,al ;mjb002 10's place to al
xor ah,ah ;mjb002 ah not wanted
mov cl,4 ;mjb002 shift count
shr ax,cl ;mjb004 swap nibbles
mov cl,10 ;mjb002 convert al to ...
mul cl ;mjb002 ... its binary value
add al,bl ;mjb002 add in units
ret ;mjb002
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