发明名称 |
System for emulating I/O device requests through status word locations corresponding to respective device addresses having read/write locations and status information |
摘要 |
In the system of the present invention, a specialized form of read-ahead, write-behind buffering is provided which enables the host processing system to provide timely responses to device requests that are emulated by the host processor. Each input/output device request is identified by an address to which the device is purportedly mapped to. This address is translated to an address containing a status word for that particular device being emulated. Each status word contains a byte of information either to be sent to the microprocessor as a response during an I/O read operation request by the microprocessor, or to receive data written by the microprocessor in response to an I/O write operation request, and a plurality of status bits which identify the state of the data contained in the I/O status word. Thus, microprocessor I/O write operations may be quickly performed without the need for immediate response by the host processor and responses for various I/O devices emulated can be precomputed and input to the corresponding I/O status words such that when the microprocessor issues a read request to an input/output device the response may be quickly retrieved and returned back to microprocessor with little or no detected response time degradation.
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申请公布号 |
US5375225(A) |
申请公布日期 |
1994.12.20 |
申请号 |
US19910815245 |
申请日期 |
1991.12.31 |
申请人 |
SUN MICROSYSTEMS, INC. |
发明人 |
DEAN, EDWARD A.;GOLSON, STEVEN E.;MCDONALD, JOHN F. |
分类号 |
G06F13/10;G06F13/40;(IPC1-7):G06F15/16 |
主分类号 |
G06F13/10 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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