User guide

7: Host/ICP Interface
DC 900-1338I 123
ment (the disposition flag is then ignored in all other buffers of
the queue element).
POST_BUF, FREE_BUF, TOKEN_BUF,
and
REL_BUF are valid in all buffers and apply only to an indi-
vidual buffer. For example, in a queue element consisting of
only one buffer,
POST_QE is equivalent to POST_BUF, but for
a multiple-buffer queue element, the value
POST_QE in the
first buffer indicates that the queue element is to be posted to a
particular queue intact, but the value
POST_BUF in every
buffer indicates that each buffer is to be posted to a queue as an
individual queue element. Section 7.2.3.1 on page 126 and
Section 7.2.4.1 on page 131 describe the use of this field in
more detail.
Disposition modifier This field provides additional information required for com-
pletion processing by XIO. What is contained in this field
depends on the value of the disposition flag, as follows:
7.2.2 Queue Element Initialization
For the utility task to communicate with the host, it must post at least three node dec-
laration queue elements, described in Section 7.2.3, to XIO’s public node declaration
queue during its initialization. Two of these, the main node and the priority node, are
the conduits for passing information from the host to the ICP. The remaining nodes
Disposition Flag Disposition Modifier
POST_QE Queue ID
FREE_QE Non-zero value to be cleared
TOKEN_QE Resource ID
POST_BUF Queue ID
FREE_BUF Non-zero value to be cleared
TOKEN_BUF Resource ID
REL_BUF Not used