Computer system which overrides write protection status during execution in system management mode
AssigneeCompaq Computer Corporation
InventorGary W. Thome
Life of this patent
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AssigneeCompaq Computer Corporation
InventorGary W. Thome
Estimating the term…
A memory controller which makes maximum use of any processor pipelining and runs a large number of cycles concurrently. The memory controller can utilize different speed memory devices at their desired optimal speeds. The functions are performed by a plurality of simple, interdependent state machines, each responsible for one small portion of the overall operation. As each state machine reaches has completed its function, it notifies a related state machine that it can now proceed and proceeds to wait for its next start or proceed indication. The next state machine operates in a similar fashion. The state machines responsible for the earlier portions of a cycle have started their tasks on the next cycle before the state machines responsible for the later portions of the cycle have completed their tasks. The memory controller is logically organized as three main blocks, a front end block, a memory block and a host block, each being responsible for interactions with its related bus and components and interacting with the various other blocks for handshaking. The memory controller operates in system management mode to override any write protect status of memory so that the SMRAM can be located in the main memory space and be write protected during normal operations but be full usable during system management mode.
A method for operating a computer system having several operating modes, the operating modes including a system management mode and being operable in the main memory space of the computer, each of the operating modes providing identical bus cycles for accessing the main memory space, the method comprising the steps of:
A computer system having several operating modes, the operating modes including a system management mode and being operable in the main memory space of the computer, each of the operating modes providing identical bus cycles for accessing the main memory space, the computer system comprising:
A computer system comprising:
Dependencies are inferred from the claim text.