[nhc-users] Maximum Heap Size

[Malcolm Wallace]

Arunkumar S Jadhav <arunk at it.iitb.ac.in> writes:

> Am I right in assuming that nhc98 uses only 29 (out of possible 32) bits
> for addressing. Because, the top bit is used for ZAP, and least two bits
> are used to differentiate between various data nodes and so on.

Yes.  (However, we are thinking about changing the representation of
the ZAP information to free-up the top bit, and see below for the
other two bits.)

> If this is the case then, we can't allocate more than 2^29 bytes or
> 2^27 (i.e 128 Mega Words) words for the total heap size 

No.  A heap pointer is always aligned to a 4-byte boundary, which
is why we can use the bottom two bits for other purposes.  Thus,
the maximum heap size is indeed 2^31 bytes = 2^29 words.

Regards,
    Malcolm