Parallel Computer Architecture

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CHAPTER

7 Scalable Multiprocessors

The "system" execution context has priority over the "user" context. The instruc-

tion set includes a segmented memory model, with one segment being a special on-

chip message input queue. There is also a message output port for each context. The

first word of the network transaction is specified as being the address of the handler

for the message. Whenever the user context is idle and a message is present in the

input queue, the head of the message is automatically loaded into the program

counter and an address register is set up to reference the rest of the message. The

handler must extract the messag