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MIPS R10000 Microprocessor User's Manual - SGI TechPubs Library

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86 Chapter 6.<br />

6.9 System Interface Requests and Responses<br />

Processor Requests<br />

The System interface supports the following:<br />

• processor request<br />

• external response<br />

• external request<br />

• processor response<br />

The following sections describe these request and response types, and their<br />

operations.<br />

Processor requests are generated by the processor when it requires a system<br />

resource. The following processor requests are supported:<br />

• coherent block read shared request<br />

• coherent block read exclusive request<br />

• noncoherent block read request<br />

• double/single/partial-word read request<br />

• block write request<br />

• double/single/partial-word write request<br />

• upgrade request<br />

• eliminate request<br />

Processor write and eliminate requests do not require or expect a response by the<br />

external agent. However, if an external agent detects an error in a processor write<br />

or eliminate request, it may use an interrupt to signal the processor. It is not<br />

possible to generate precise exceptions for processor write and eliminate requests<br />

for which an external agent detects an error.<br />

Processor read and upgrade requests require some type of response by the external<br />

agent.<br />

Version 2.0 of January 29, 1997 <strong>MIPS</strong> <strong>R10000</strong> <strong>Microprocessor</strong> <strong>User's</strong> <strong>Manual</strong>

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