English Amiga Board - View Single Post - non-system startup code time/clock problem

phx · 18 June 2015, 11:15

Very good. There is just one disadvantage: you need an RTC and at least OS2.0(?) for battclock.resource.

Maybe it also works without RTC, by remembering the system time and resetting the TOD to zero at the beginning of your program. At the end you will set the system time to the saved timeval + the new TOD count. As long as your code doesn't mess with the TOD, and as long as the OS and the interrupts are disabled, I see no reason why that shouldn't work.

At the start of your program, get SysTime and reset TOD:

Code:

; a6 = TimerDevice
        lea     timval,a0
        jsr     -66(a6)                 ; GetSysTime

        ; disable interrupts, take over system
        ; ...

        ; reset TOD
        lea     $bfe001,a0              ; CIA-A
        moveq   #0,d0
        move.b  d0,$a00(a0)             ; TODHI 
        move.b  d0,$900(a0)             ; TODMID
        move.b  d0,$800(a0)             ; TODLO

At the end of your program, use the TOD to set the new SysTime:

Code:

        lea     $bfe001,a0
        moveq   #0,d0
        move.b  $a00(a0),d0             ; TODHI
        lsl.w   #8,d0
        move.b  $900(a0),d0             ; TODMID
        lsl.l   #8,d0
        move.b  $800(a0),d0             ; TODLO

        ; restore system, enable interrupts
        ; ...
; a6 = TimerDevice
; d0 = TOD count since start
        lea     timeval,a0
        add.l   TV_MICRO(a0),d0
        divu    TD_TODHERTZ(a6),d0
        move.l  d0,d1
        ext.l   d0
        add.l   d0,TV_SECS(a0)
        swap    d1
        ext.l   d1
        move.l  d1,TV_MICRO(a0)

; set system time, pass timeval to TR_SETSYSTIME
; ...

18 June 2015, 11:15	#25
phx Natteravn Join Date: Nov 2009 Location: Herford / Germany Posts: 2,510	Very good. There is just one disadvantage: you need an RTC and at least OS2.0(?) for battclock.resource. Maybe it also works without RTC, by remembering the system time and resetting the TOD to zero at the beginning of your program. At the end you will set the system time to the saved timeval + the new TOD count. As long as your code doesn't mess with the TOD, and as long as the OS and the interrupts are disabled, I see no reason why that shouldn't work. At the start of your program, get SysTime and reset TOD: Code: ; a6 = TimerDevice lea timval,a0 jsr -66(a6) ; GetSysTime ; disable interrupts, take over system ; ... ; reset TOD lea $bfe001,a0 ; CIA-A moveq #0,d0 move.b d0,$a00(a0) ; TODHI move.b d0,$900(a0) ; TODMID move.b d0,$800(a0) ; TODLO At the end of your program, use the TOD to set the new SysTime: Code: lea $bfe001,a0 moveq #0,d0 move.b $a00(a0),d0 ; TODHI lsl.w #8,d0 move.b $900(a0),d0 ; TODMID lsl.l #8,d0 move.b $800(a0),d0 ; TODLO ; restore system, enable interrupts ; ... ; a6 = TimerDevice ; d0 = TOD count since start lea timeval,a0 add.l TV_MICRO(a0),d0 divu TD_TODHERTZ(a6),d0 move.l d0,d1 ext.l d0 add.l d0,TV_SECS(a0) swap d1 ext.l d1 move.l d1,TV_MICRO(a0) ; set system time, pass timeval to TR_SETSYSTIME ; ...