| Title: | Atari ST, TT, & Falcon |
| Notice: | Please read note 1.0 and its replies before posting! |
| Moderator: | FUNYET::ANDERSON |
| Created: | Mon Apr 04 1988 |
| Last Modified: | Tue May 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 1433 |
| Total number of notes: | 10312 |
Hello friends,
I'm trying to rpogram interrupts but get 2 bombs when I press a
key. Here's what I'm doing:
MOVE.L KBVECT,-(SP) ;Interrupt routine address
MOVE.W #6,-(SP) ;Keyboard
MOVE.W #13,-(SP) ;XBIOS MFPINT
TRAP #14 ;XBIOS call
ADDQ.L #8,SP ;Cleanup
MOVE.W #6,-(SP) ;Enable keyboard interrupts
MOVE.W #13,-(SP) ;XBIOS JENABINT
TRAP #14 ;XBIOS Call
ADDQ.L #4,SP ;Cleanup
KBVECT: Some routine
RTS
I'm probably doing something very basically wrong but not being
a programmer I don't see why I'm getting the bombs. Any help, in
simple language please, would be greatly appreciated.
Thanks.
...Howard
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 680.1 | Address rather than contents ? | 1075::FORSTER | Thu Nov 23 1989 09:03 | 13 | |
It may be a typo on your part, but shouldn't
MOVE.L KBVECT,-(SP)
be
MOVE.L #KBVECT,-(SP)
or
PEA KBVECT
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| 680.2 | ex | SUBURB::JAMESH | Nit Picking is my Business | Thu Nov 23 1989 11:03 | 5 |
Thanks for your reply. I took the instruction from the Abacus ST
Internals page 178 which actually shows: move.l vector,-(sp). I'll
try again tonight with #KBVECT.
Thanks again.
...Howard
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| 680.3 | Not so easy | HAM::LITSCH | Fri Nov 24 1989 09:23 | 31 | |
Hello Howard!
Creating an own interrupt service routine is especially difficult for
the ST. Besides the problem mentioned in the previous reply, there are
more of them:
- The BIOS already uses interrupt-driven keyboard-input. If you change
that vector, you essentially disable all standard keyboard input.
- Not only keystrokes, but also mouse, joystick, and keyboard-clock
send data through the very same line, so you have to handle them as
well.
- The 6850s for keyboard and MIDI share the same interrupt line, you
have to handle them both.
- It may happen that another input arrives while you are handling the
current one. This will NOT create another interrupt because of the
edge-triggered nature of them. You have to do a loop until there is no
more data in any of the 6850s.
Another bug in your code:
Interrupt routines have to end using RTE, not RTS.
Watch out for this:
ALL registers (except SR, the 68k handles this for you) MUST be
restored to their old values before leaving the routine, so use
> KBVECT: movem.l d0-d7/a0-a6,-(a7)
> Some routine
> movem.l (a7)+,d0-d7/a0-a6
> RTS
Depending of your use of registers you may leave out the unaltered ones
in the movem instructions.
Jens
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