Missing Register Field specifications

[UshaKumi]

I am new to IPXACT files. I want to know the significance of missing register fields in some register specifications. For example, in the following fields, field YYY and XXX have a gap of 3 missing fields.  Can the missing fields be considered "reserved"?

<ipxact:field>
            <ipxact:name>YYY</ipxact:name>
            <ipxact:description>......</ipxact:description>

<ipxact:bitOffset>4</ipxact:bitOffset>
            .

            .
            <ipxact:bitWidth>5</ipxact:bitWidth>
            <ipxact:access>read-only</ipxact:access>
          </ipxact:field>
          <ipxact:field>
            <ipxact:name>XXX</ipxact:name>
            <ipxact:description>.....</ipxact:description>
            <ipxact:bitOffset>12</ipxact:bitOffset>

[Richard Weber]

Hello UshaKumi,

It would be better to describe the register bit positions without a field specification to be "unspecified" instead of "reserved". The word "reserved" does not have a specific agreed meaning in the industry, and, the register bit positions without a field specification could have many different software behaviors or hardware implementations.  Also, these bit position could be actual fields which the IP provider has chosen exclude from the IP-XACT file.  If your tool flow requires that every bit in a register be associated with a field you can always ask the IP file provider if they could generate an IP-XACT file with all the register bits associated with fields. The IP provider probably has more information about the design to fill in the register with appropriate field specifications.