Synopsis

void ObtainBattSemaphore();

Function

Gain exclusive access to the battery backed up memory. Reads and
writes of related fields have to be bracketed by this and
ReleaseBattSemaphore(), so that they are not interleaved with
those of another task.

Notes

ReadBattMem() and WriteBattMem() are safe to call on their own;
the semaphore is only needed to keep a group of them together.

See also

ReleaseBattSemaphore()

Synopsis

ULONG ReadBattMem(
         APTR buffer,
         ULONG offset,
         ULONG length );

Function

Copy a field out of the battery backed up memory into a buffer.

Inputs

buffer - where to put the field. It has to be large enough to hold
         (length + 7) / 8 bytes.
offset - bit offset of the field within the battery memory.
length - size of the field in BITS, not bytes.

Result

Always zero.

Notes

Bit offsets and lengths beyond the end of the battery memory read
back as zero rather than failing. See <resources/battmembitsamiga.h>
and <resources/battmembitsshared.h> for the assigned fields.

A trailing partial byte is right aligned in the last byte written.

See also

WriteBattMem() ObtainBattSemaphore()

Synopsis

void ReleaseBattSemaphore();

Function

Give up the exclusive access to the battery backed up memory
gained with ObtainBattSemaphore().

See also

ObtainBattSemaphore()

Synopsis

ULONG WriteBattMem(
         CONST_APTR buffer,
         ULONG offset,
         ULONG length );

Function

Copy a field from a buffer into the battery backed up memory.

Inputs

buffer - the field to store, (length + 7) / 8 bytes.
offset - bit offset of the field within the battery memory.
length - size of the field in BITS, not bytes.

Result

Always zero.

Notes

Writes that run past the end of the battery memory are truncated
rather than failing. See <resources/battmembitsamiga.h> and
<resources/battmembitsshared.h> for the assigned fields.

A trailing partial byte is taken right aligned from the last byte
of the buffer.

See also

ReadBattMem() ObtainBattSemaphore()