Advanced Micro Devices Corporation

Delco Electronics Corporation

Intel Corporation

Advanced Micro Design, Inc.

James K Pickett

Thang M Tran

Michael A Filippo

Benjamin T Sander

Brian D McMinn

Rupaka Mahalingaiah

Kevin Michael Lepak

Mitchell K Alsup

David S Christie

Roger Dwain Isaac

Rama S Gopal

James S Roberts

W Kurt Lewchuk

David B Witt

Stephan G Meier

Kevin John McGrath

Brian S Morris

Bruce Querbach

Dong Wang

Woojong Han

Gregory William Smaus

Mohamed Arafa

Ashraf Ahmed

Mani Prakash

John K Grooms

Matthew D Sale

Edward L Payton

David Wayne Stringfellow

H S Ramagopal

Philip A Inman

Methods and apparatus related to supporting both DDR (Double Data Rate) and NVM (Non-Volatile Memory) DIMM (Dual Inline Memory Module) on the same memory slot are described. In one embodiment, a DIMM comprises volatile memory and non-volatile memory, and data is communicated with the volatile memory and the non-volatile memory via a single memory slot. Other embodiments are also disclosed and claimed.

Supporting multiple memory types in a memory slot

A prefetch unit for use with a cache subsystem. The prefetch unit includes a stream storage coupled to a prefetch unit. The stream storage may include a plurality of locations configured to store a plurality of entries each corresponding to a respective range of prefetch addresses. The prefetch control may be configured to prefetch an address in response to receiving a cache access request including an address that is within the respective range of prefetch addresses of any of the plurality of entries.

Prefetch unit for use with a cache memory subsystem of a cache memory hierarchy

A processor may include a scheduler configured to issue operations and a load store unit configured to execute memory operations issued by the scheduler. The load store unit is configured to store information identifying memory operations issued to the load store unit. In response to detection of incorrect data speculation for one of the issued memory operations, the load store unit is configured to replay at least one of the issued memory operations by providing an indication to the scheduler. The scheduler is configured to responsively reissue the memory operations identified by the load store unit.

Processor with dependence mechanism to predict whether a load is dependent on older store

A microprocessor may include one or more functional units configured to execute operations, a scheduler configured to issue operations to the functional units for execution, and at least one replay detection unit. The scheduler may be configured to maintain state information for each operation. Such state information may, among other things, indicate whether an associated operation has completed execution. The replay detection unit may be configured to detect that one of the operations in the scheduler should be replayed. If an instance of that operation is currently being executed by one of the functional units when operation is detected as needing to be replayed, the replay detection unit is configured to inhibit an update to the state information for that operation in response to execution of the in-flight instance of the operation. Various embodiments of computer systems may include such a microprocessor.

System and method to prevent in-flight instances of operations from disrupting operation replay within a data-speculative microprocessor

A microprocessor may include a dispatch unit configured to dispatch load and store operations and a load store unit configured to store information associated with load and store operations dispatched by the dispatch unit. The load store unit includes a STLF (Store-to-Load Forwarding) buffer that includes a plurality of entries. The load store unit is configured to generate an index dependent on at least a portion of an address of a load operation, to use the index to select one of the plurality of entries, and to forward data included in the one of the plurality of entries as a result of the load operation.

Store-to-load forwarding buffer using indexed lookup

A microprocessor may include a retire queue and one or more data speculation verification units. The data speculation verification units are each configured to verify data speculation performed on operations. Each data speculation verification unit generates a respective speculation pointer identifying outstanding operations on which data speculation has been verified by that data speculation verification unit. The retire queue is configured to selectively retire operations dependent on the speculation pointer received from each of the data speculation verification units.

Speculation pointers to identify data-speculative operations in microprocessor

A cache memory subsystem including a fixed latency read/write pipeline. The cache memory subsystem includes a cache storage which may be configured to store a plurality of cache lines of data. The cache memory subsystem further includes a scheduler which may be configured to schedule reads and writes of information associated with the cache storage using a fixed latency pipeline. In response to scheduling a read request, the scheduler may be further configured to cause an associated write to occur a fixed number of cycles after the scheduling of the read request.

Cache memory subsystem including a fixed latency R/W pipeline

A system may include a dispatch unit, a scheduler, and an execution core. The dispatch unit may be configured to modify a load operation to include a register-to-register move operation in response to an indication that a speculative result of the load operation is linked to a data value identified by a first tag. The scheduler may be coupled to the dispatch unit and configured to issue the register-to-register move operation in response to availability of the data value. The execution core may be configured to execute the register-to-register move operation by outputting the data value and a tag indicating that the data value is the result of the load operation.

System and method for modifying a load operation to include a register-to-register move operation in order to forward speculative load results to a dependent operation

A microprocessor may include a scheduler configured to issue operations and a load store unit configured to execute memory operations issued by the scheduler. The load store unit is configured to store information identifying memory operations issued to the load store unit. In response to detection of incorrect data speculation for one of the issued memory operations, the load store unit is configured to replay at least one of the issued memory operations by providing an indication to the scheduler. The scheduler is configured to responsively reissue the memory operations identified by the load store unit.

Load store unit with replay mechanism

A system may include an instruction cache, a trace cache including a plurality of trace cache entries, and a trace generator coupled to the instruction cache and the trace cache. The trace generator may be configured to receive a group of instructions output by the instruction cache for storage in one of the plurality of trace cache entries. The trace generator may be configured to detect an exceptional instruction within the group of instructions and to prevent the exceptional instruction from being stored in a same one of the plurality of trace cache entries as any non-exceptional instruction.

System and method for handling exceptional instructions in a trace cache based processor

A processor may include a stack file and an execution core. The stack file may include an entry configured to store an addressing pattern and a tag. The addressing pattern identifies a memory location within the stack area of memory. The stack file may be configured to link a data value identified by the tag stored in the entry to the speculative result of a memory operation if the addressing pattern of the memory operation matches the addressing pattern stored in the entry. The execution core may be configured to access the speculative result when executing another operation that is dependent on the memory operation.

Data speculation based on stack-relative addressing patterns

A method and apparatus for retaining flag values when an associated data value dies. A first storage circuit includes a free list for storing physical register names (PRNs) and indications indicative of whether a physical register associated with a PRN was assigned to store a logical register result and flag results of a first instruction and a logical register result and a subsequent instruction which overwrites the logical register result but not the flags. A second storage circuit stores PRNs separate from the free list. The first and second storage circuits output first and second PRNs to a selection circuit. If the first indication (associated with the first PRN) is in a first state, the selection circuit may provide the first PRN to a mapper for assignment to a logical register. If the first indication is in a second state, the second PRN may be provided to the mapper.

Retaining flag value associated with dead result data in freed rename physical register with an indicator to select set-aside register instead for renaming

A system may include a memory file, which includes an entry configured to store a first addressing pattern and a first tag, and an execution core coupled to the memory file. The memory file may be configured to compare the first addressing pattern included in the entry to a second addressing pattern of a load operation. If the second addressing pattern matches the first addressing pattern stored in the entry, the memory file is configured to link a data value identified by the first tag to a speculative result of the load operation. The execution core is configured to access the speculative result when executing a second operation that is dependent on the load operation.

System and method for linking speculative results of load operations to register values

A system may include a memory file and an execution core. The memory file may include an entry configured to store an addressing pattern and a tag. If an addressing pattern of a memory operation matches the addressing pattern stored in the entry, the memory file may be configured to link a data value identified by the tag to a speculative result of the memory operation. The addressing pattern of the memory operation includes an identifier of a logical register, and the memory file may be configured to predict whether the logical register is being specified as a general purpose register or a stack frame pointer register in order to determine whether the addressing pattern of the memory operation matches the addressing pattern stored in the entry. The execution core may be configured to access the speculative result when executing another operation that is dependent on the memory operation.

Data speculation based on addressing patterns identifying dual-purpose register

A microcode instruction unit for a processor may include a microcode memory having entries for storing microcode instructions. A decoder for the microcode memory may decode microcode addresses to select entries of the microcode memory. A microcode entry point generator may receive complex instructions and provide a microcode entry point address to the decoder for each complex instruction. Each microcode entry point address may have a bit-width greater than needed to encode all the entries of the microcode memory. The microcode memory decoder may decode each microcode entry point address to select an entry in the microcode memory storing the beginning of a microcode routine to implement the corresponding complex instruction. The decoder may sparsely decode the microcode address range so that not all entries of said microcode memory are sequentially addressed.

Growing community of inventors

Austin, TX, United States of America

James K Pickett