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TABLE OF CONTENTS
disk.resource/AllocUnit
disk.resource/FreeUnit
disk.resource/GetUnit
disk.resource/GetUnitID
disk.resource/GiveUnit
disk.resource/ReadUnitID
disk.resource/AllocUnit disk.resource/AllocUnit
NAME
AllocUnit - allocate a unit of the disk
SYNOPSIS
Success = AllocUnit( unitNum ), DRResource
D0 D0 A6
BOOL AllocUnit(LONG);
FUNCTION
This routine allocates one of the units of the disk. It should
be called before trying to use the disk (via GetUnit).
In reality, it is perfectly fine to use GetUnit/GiveUnit if AllocUnit
fails. Do NOT call FreeUnit if AllocUnit did not succeed. This
has been the case for all revisions of disk.resource.
INPUTS
unitNum -- a legal unit number (zero through three)
RESULTS
Success -- nonzero if successful. zero on failure.
EXCEPTIONS
SEE ALSO
BUGS
disk.resource/FreeUnit disk.resource/FreeUnit
NAME
FreeUnit - deallocate the disk
SYNOPSIS
FreeUnit( unitNum ), DRResource
D0 A6
void FreeUnit(LONG);
FUNCTION
This routine deallocates one of the units of the disk. It should
be called when done with the disk. Do not call it if you did
no successfully allocate the disk (there is no protection -- you
will probably crash the disk system).
INPUTS
unitNum -- a legal unit number (zero through three)
RESULTS
EXCEPTIONS
SEE ALSO
FreeUnit
BUGS
Doesn't check if you own the unit, or even if anyone owns it.
disk.resource/GetUnit disk.resource/GetUnit
NAME
GetUnit - allocate the disk for a driver
SYNOPSIS
lastDriver = GetUnit( unitPointer ), DRResource
D0 A1 A6
struct DiscResourceUnit *GetUnit(struct DiscResourceUnit *);
FUNCTION
This routine allocates the disk to a driver. It is either
immediately available, or the request is saved until the disk
is available. When it is available, your unitPointer is
sent back to you (via ReplyMsg). You may then reattempt the
GetUnit.
Allocating the disk allows you to use the disk's resources.
Remember however that there are four units to the disk; you are
only one of them. Please be polite to the other units (by never
selecting them, and by not leaving interrupts enabled, etc.).
When you are done, please leave the disk in the following state:
dmacon dma bit ON
dsklen dma bit OFF (write a #DSKDMAOFF to dsklen)
adkcon disk bits -- any way you want
entena:disk sync and disk block interrupts -- Both DISABLED
CIA resource index interrupt -- DISABLED
8520 outputs -- doesn't matter, because all bits will be
set to inactive by the resource.
8520 data direction regs -- restore to original state.
NOTE: GetUnit() does NOT turn on the interrupts for you.
You must use AbleICR (for the index interrupt) or intena
(for the diskbyte and diskblock interrupts) to turn them
on. You should turn them off before calling GiveUnit,
as stated above.
INPUTS
unitPtr - a pointer you your disk resource unit structure.
Note that the message filed of the structure MUST
be a valid message, ready to be replied to. Make sure
ln_Name points to a null-terminated string, preferably
one that identifies your program.
You need to set up the three interrupt structures,
in particular the IS_DATA and IS_CODE fields. Set them
to NULL if you don't need that interrupt. Also, set
the ln_Type of the interrupt structure to NT_INTERRUPT.
WARNING: don't turn on a disk resource interrupt unless
the IS_CODE for that interrupt points to executable code!
IS_CODE will be called with IS_DATA in A1 when the
interrupt occurs. Preserve all regs but D0/D1/A0/A1.
Do not make assumptions about A0.
RESULTS
lastDriver - if the disk is not busy, then the last unit
to use the disk is returned. This may be used to
see if a driver needs to reset device registers.
(If you were the last user, then no one has changed
any of the registers. If someone else has used it,
then any allowable changes may have been made). If the
disk is busy, then a null is returned.
EXCEPTIONS
SEE ALSO
GiveUnit
BUGS
disk.resource/GetUnitID disk.resource/GetUnitID
NAME
GetUnitID - find out what type of disk is out there
SYNOPSIS
idtype = GetUnitID( unitNum ), DRResource
D0 D0 A6
LONG GetUnitID(LONG);
FUNCTION
Gets the drive ID for a given unit. Note that this value may
change if someone calls ReadUnitID, and the drive id changes.
INPUTS
unitNum -- a legal unit number (zero through three)
RESULTS
idtype -- the type of the disk drive. Standard types are
defined in the resource include file.
EXCEPTIONS
SEE ALSO
ReadUnitID
BUGS
disk.resource/GiveUnit disk.resource/GiveUnit
NAME
GiveUnit - Free the disk back up
SYNOPSIS
GiveUnit(), DRResource
A6
void GiveUnit();
FUNCTION
This routine frees the disk after a driver is done with it.
If others are waiting, it will notify them.
INPUTS
RESULTS
EXCEPTIONS
SEE ALSO
GetUnit
BUGS
In pre-V36, GiveUnit didn't check if you owned the unit. A patch
for this was part of 1.3.1 SetPatch. Fixed in V36.
disk.resource/ReadUnitID disk.resource/ReadUnitID
NAME
ReadUnitID - reread and return the type of drive (V37)
SYNOPSIS
idtype = ReadUnitID( unitNum ), DRResource
D0 D0 A6
ULONG ReadUnitID(LONG);
FUNCTION
Rereads the drive id for a specific unit (for handling drives
that change ID according to what sort of disk is in them. You
MUST have done a GetUnit before calling this function!
INPUTS
unitNum -- a legal unit number (zero through three)
RESULTS
idtype -- the type of the disk drive. Standard types are
defined in the resource include file.
EXCEPTIONS
SEE ALSO
GetUnitID
BUGS