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School of Computer Science & Engineering
University of New South Wales
 Advanced Operating Systems 
 COMP9242 2002/S2 

Memory message format

message header

fpage descriptors

by-value data

string dopes

• Fpages are expected only if
  • the -bit is set in the message descriptor, and
  • all register data consists of valid fpages.
• Fpage processing stops if invalid fpage descriptor found.
• Remainder of data (up to size given in header) is simply copied.
• String descriptors (``dopes'') immediately follow in-line data in memory.

Note: present R4k implementation allows no more than 4 fpages
(no fpage descriptors in memory).

This is not a problem in practice.

.