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From: rhialto@cs.kun.nl (Olaf Seibert)
Newsgroups: comp.sys.amiga,comp.sys.amiga.tech
Subject: Re: Should CrossDos/MSH work on my 3000?
Summary: Is this documented now? (see below)
Message-ID: <2286@wn1.sci.kun.nl>
Date: 12 Oct 90 10:50:20 GMT
References: <08Oct90.151432.944@ckctpa.UUCP> <7811@ucdavis.ucdavis.edu>
Sender: root@sci.kun.nl
Followup-To: comp.sys.amiga.tech
Organization: University of Nijmegen, The Netherlands
Lines: 119

In article <7811@ucdavis.ucdavis.edu> zerkle@iris.ucdavis.edu (Dan Zerkle) writes:
>In article <08Oct90.151432.944@ckctpa.UUCP> crash@ckctpa.UUCP (Frank J. Edwards) writes:
>>[MSH does not work on a 3000]
>
>I have been able to get MSH to read but not write (or format).

I think that the messydisk.device indefinitely waits for an index
interrupt. The way these things are installed is not really documented,
as far as I know, except by suggestive names in a structure.  What
usually is the problem when messydisk can't write, is that the
IndexIntCode doesn't get called for some reason. (Usually these are
hardware problems, so not my problem ;-) The ~~~ marked part is what is
questionable. But if it can read, the block interrupt works, so why
doesn't the index interrupt work?  Specifically, what I do is the
following: (file devio.c excerpted)

/*-
 * $Id: devio.c,v 1.30 90/06/04 23:18:52 Rhialto Rel $
-*/

struct DiskResource *DRResource;/* Argh! A global variable! */
void *CiaBResource;		/* And yet another! */


_SafeEnableICR: move.l	_CiaBResource,a6
		move.b	4+1(sp),d0
		jsr	_LVOSetICR(a6)      ; clear pending interrupt
		move.b	4+1(sp),d0
		or.b	#$80,d0 	    ; then enable it
		jsr	_LVOAbleICR(a6)
		rts
;;;;
;
;   Disk index interrupt code.
;   is_Data (A1) is the value to stuff into the DSKLEN register.
;   A0 points to the custom chips already.
;   It then enables the disk block interrupt and disables the
;   index interrupt.

_IndexIntCode:
;	 movem.l A2-A4/D2-D7,-(sp)
	move.w	#dskdmaoff,Dsklen(a0)
	move.w	a1,Dsklen(a0)
	move.w	a1,Dsklen(a0)       ; this enables the DMA
	move.w	#intf_setclr|intf_dskblk,Intena(a0)
	move.l	_CiaBResource,a6
	move.b	#ciaicrf_flg,d0
	jsr	_LVOAbleICR(a6)     ; disable index interrupt
;	 movem.l (sp)+,A2-A4/D2-D7
	rts
;;;;
;
;   Disk DMA finished interrupt code.
;   (a1) is the task to Signal, 4(a1) is the signal mask to use.
;   Disables the disk block finished interrupt.

_DskBlkIntCode:
	move.w	#dskdmaoff,Dsklen(a0)   ; disable disk DMA
	move.w	#intf_dskblk,Intena(a0) ; disable the interrupt
	move.w	#intf_dskblk,Intreq(a0) ; clear 'diskblock finished' flag
	move.l	4(a1),d0            ; signal mask
	move.l	(a1),a1             ; task to signal
	jsr	_LVOSignal(a6)
	rts

    struct {
	struct Task *task;
	ulong signal;
    } tasksig;

    tasksig.task = FindTask(NULL);
    tasksig.signal = 1L << unit->mu_DmaSignal;

    (this is done once on the initialisation of the device's unit:)
    unit->mu_DRUnit.dru_Index.is_Node.ln_Pri = 32; /* high pri for index int */
    unit->mu_DRUnit.dru_Index.is_Code = IndexIntCode;
    unit->mu_DRUnit.dru_DiscBlock.is_Code = DskBlkIntCode;

    unit->mu_DRUnit.dru_Index.is_Data = (APTR) ((WLEN >> 1)|DSKDMAEN| dskwrite);
    unit->mu_DRUnit.dru_DiscBlock.is_Data = (APTR) &tasksig;

    /* Clear signal bit */
    SetSignal(0L, tasksig.signal);

    /* Allocate drive and install index and block interrupts */
		      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    GetDrive(&unit->mu_DRUnit);

    /* Select correct drive and side */
    /* Set up disk parameters */
    /* Set up disk buffer address */
    /* Enable disk DMA */
	/* Enable disk index interrupt to start the whole thing. */
	SafeEnableICR((int) CIAICRF_FLG);
    Wait(tasksig.signal);
    FreeDrive();

void	       *
GetDrive(drunit)
register struct DiskResourceUnit *drunit;
{
	Basically just GetUnit(drunit);
	Note no AllocUnit() is done, because trackdisk already
	has done this so we fail if we try.
}

void
FreeDrive()
{
    GiveUnit();
}

>             Dan Zerkle  zerkle@iris.ucdavis.edu  (916) 754-0240
--
Olaf 'Rhialto' Seibert                               rhialto@cs.kun.nl
How can you be so stupid if you're identical to me? -Robert Silverberg
--
Olaf 'Rhialto' Seibert                               rhialto@cs.kun.nl
How can you be so stupid if you're identical to me? -Robert Silverberg