[comp.sys.amiga] Audio Interrupt

c55-hd@buddy.Berkeley.EDU (Bob Johnsen) (11/12/86)

[]

Where does one put the address for a level 4 audio interrupt handler?
I thought it was $74, but there seems to be a problem.
I set intena bits 15 14 and 7, start the dma, get the tone....but
the amiga immediately crashed.

Also, I am using the manx assembler that comes with aztec c and am wondering
if anyone has found any bugs or quirks in it.

Ex:       move.l  d0,label
   This will generate a PC relative error during link.

Thanks, Bob Johnsen
ucbvax!buddy!c55-hd

dillon@CORY.BERKELEY.EDU (Matt Dillon) (11/13/86)

	I don't have the RKM manual with me at the moment, but you should
*NOT* emplace interrupts manually.... use the Exec call to set the
interrupt vector.

					-Matt

terryl@tekcrl.UUCP (11/13/86)

In article <937@zen.BERKELEY.EDU> c55-hd@buddy.Berkeley.EDU (Bob Johnsen) writes:
 >Where does one put the address for a level 4 audio interrupt handler?
 >I thought it was $74, but there seems to be a problem.
 >I set intena bits 15 14 and 7, start the dma, get the tone....but
 >the amiga immediately crashed.

     Not knowing anything about the Amiga, but knowing quite a bit about the
various flavors of 68xxx processors, the level 4 autovector is at 70 (hex, that
is; I'm assuming $74 is hex 74).

grr@cbmvax.cbm.UUCP (George Robbins) (11/19/86)

In article <1188@tekcrl.UUCP> terryl@tekcrl.UUCP writes:
>In article <937@zen.BERKELEY.EDU> c55-hd@buddy.Berkeley.EDU (Bob Johnsen) writes:
> >Where does one put the address for a level 4 audio interrupt handler?
> >I thought it was $74, but there seems to be a problem.
> >I set intena bits 15 14 and 7, start the dma, get the tone....but
> >the amiga immediately crashed.
>
>     Not knowing anything about the Amiga, but knowing quite a bit about the
>various flavors of 68xxx processors, the level 4 autovector is at 70 (hex, that
>is; I'm assuming $74 is hex 74).

Well, actually the Amiga doesn't auto-vector.  Because of the way the logic
is implemented, it fetches the interrupt identifier from "ROM" at address
FFFFFX where X is the interrupt level shifted left a bit.  In release 1.2,
the interrupt identifiers thusly fetched correspond to the autovector
locations, which from a software point of view is identical to autovector.
I've heard that under some previous releases, all the identifiers were the
same, but don't know if this is/was really the case.

-- 
George Robbins - now working for,	uucp: {ihnp4|seismo|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@seismo.css.GOV
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)