International Business Machines Corporation

Jafar Nahidi

Dung Q Nguyen

Maureen Anne Delaney

Saiful Islam

James Wilson Bishop

Joel Abraham Silberman

Mary Douglass Brown

Sam Gat-Shang Chu

Robert Allen Cordes

Hung Qui Le

Brian William Thompto

Jeffrey Carl Brownscheidle

Brian William Curran

Scott Barnett Swaney

Vikas Agarwal

Jose Angel Paredes

Taqi Nasser Buti

Sam G Chu

Michael James Mack

Bjorn P Christensen

Zakaria Mahmood Khwaja

Yonatan Mittlefehldt

An information handling system includes a processor with an instruction issue queue (IQ) that may perform age tracking operations. The issue queue IQ maintains or stores instructions that may issue out-of-order in an internal data store (IDS). The IDS organizes instructions in a queue position (QPOS) addressing arrangement. An age matrix of the IQ maintains a record of relative instruction aging for those instructions within the IDS. The age matrix updates latches or other memory cell data to reflect the changes in IDS instruction ages during a dispatch operation into the IQ. During dispatch of one or more instructions, the age matrix may update only those latches that require data change to reflect changing IDS instruction ages. The age matrix employs row and column data and clock controls to individually update those latches requiring update.

Processor including age tracking of issue queue instructions

An information handling system includes a processor with an instruction issue queue (IQ) that may perform age tracking operations. The issue queue IQ maintains or stores instructions that may issue out-of-order in an internal data store IDS. The IDS organizes instructions in a queue position (QPOS) addressing arrangement. An age matrix of the IQ maintains a record of relative instruction aging for those instructions within the IDS. The age matrix updates latches or other memory cell data to reflect the changes in IDS instruction ages during a dispatch operation into the IQ. During dispatch of one or more instructions, the age matrix may update only those latches that require data change to reflect changing IDS instruction ages. The age matrix employs row and column data and clock controls to individually update those latches requiring update. The issue queue may selectively clock a row and a column of cells of the age matrix that correspond to a dispatched instruction's queue position while leaving other cells unclocked to conserve power.

An integrated circuit design is routed by first creating temporary routes in a flattened layout, generating blockage information for sub-blocks in the layout based on the temporary routes, and establishing a routing order for cells using a depth-first search. Cells in the original layout are then routed according to the routing order using the blockage information. The temporary routes are sorted into internal routes, terminal routes, and spanning routes. Blockage information for each sub-block includes a first cellview equal to the internal routes, a second cellview equal to the terminal routes plus the spanning routes, and a third cellview equal to the total tracks in the sub-block minus the first and second cellviews. The invention is particularly suited for routing a hierarchical integrated circuit design. By examining the complete hierarchy, the invention ensures that enough metal will be remaining at upper level sub-blocks to complete the routing automatically.

Statistical method for hierarchically routing layout utilizing flat route information

A processor having a dependency matrix comprises a first array comprising a plurality of first cells. A second array couples to the first array and comprises a plurality of second cells. A first write port couples to the first array and the second array and writes to the first array and the second array. A first read port couples to the first array and the second array and reads from the first array and the second array. A second read port couples to the first array and reads from the first array. A second write port couples to the second read port, reads from the second read port and writes to the second array.

Dependency matrix with reduced area and power consumption

An apparatus and method are provided for reading a plurality of consecutive entries and writing a plurality of consecutive entries with only one read address and one write address using a 2Read/2Write register file. In one exemplary embodiment, a 64 entry register file array is partitioned into four sub-arrays. Each sub-array contains sixteen entries having one or more 2Read/2Write SRAM cells. The apparatus and method provide a mechanism to write the consecutive entries by only having a 4 to 16 decode of one address. In addition, the apparatus and method provide a mechanism for reading data from the register file array using a starting read word address and two read word lines generated based on the starting read word address. The two read word lines are used to access the two read ports of the entries in the sub-arrays.

Apparatus and method for providing multiple reads/writes using a 2Read/2Write register file array

A method and apparatus are provided for dispatch group checkpointing in a microprocessor, including provisions for handling partially completed dispatch groups and instructions which modify system coherent state prior to completion. An instruction checkpoint retry mechanism is implemented to recover from soft errors in logic. The processor is able to dispatch fixed point unit (FXU), load/store unit (LSU), and floating point unit (FPU) or vector multimedia extension (VMX) instructions on the same cycle. Store data is written to a store queue when a store instruction finishes executing. The data is held in the store queue until the store instruction is checkpointed, at which point it can be released to the coherently shared level 2 (L2) cache.

Method for checkpointing instruction groups with out-of-order floating point instructions in a multi-threaded processor

Reading a plurality of consecutive entries and writing a plurality of consecutive entries with only one read address and one write address using a 2Read/2Write register file is provided. In one exemplary embodiment, a 64 entry register file array is partitioned into four sub-arrays. Each sub-array contains sixteen entries having one or more 2Read/2Write SRAM cells. A mechanism to write the consecutive entries by only having a 4 to 16 decode of one address is also provided. In addition, a mechanism for reading data from the register file array using a starting read word address and two read word lines generated based on the starting read word address is provided. The two read word lines are used to access the two read ports of the entries in the sub-arrays.

Method for providing multiple reads/writes using a 2read/2write register file array

Dynamic reformatting of a dispatch group by selective activation of inactive Start bits of instructions within the dispatch group at the time the instructions are read from the IBUF. The number of instructions in the reformatted dispatch groups can vary from as few as one instruction per group to a maximum number of instructions read from the IBUF per cycle. The reformatted dispatch groupings can be terminated after a single cycle, or they can remain reformatted for as many cycles as desired, depending upon need.

Method and apparatus for dynamic modification of microprocessor instruction group at dispatch

An apparatus and method for speeding up access time of a large register file with wrap capability are provided. With the apparatus and method, the 2:1 multiplexers in conventional register file systems are eliminated from the circuit configuration and instead, additional primary multiplexers are provided for half of the addresses, e.g., the first four sub-arrays of the register file for which the wrap capability is needed. These additional primary multiplexers receive the read address and a shifted read word line signal. The other primary multiplexer receives the read address and an unshifted read word line signal. The outputs from the shifted and non-shifted primary multiplexers are provided to a set of secondary multiplexers which multiplex bits from the outputs of the shifted and non-shifted primary multiplexers to generate the read addresses to be used by the multiple read/write register file system.

Apparatus and method for speeding up access time of a large register file with wrap capability

An instruction buffer and a method of buffering instructions. The instruction buffer including: a memory array partitioned into multiple identical memory sub-arrays arranged in sequential order from a first memory sub-array to a last memory sub-array, each memory sub-array having multiple instruction entry positions and adapted to store a different instruction of a set of concurrent instructions in a single instruction entry position of any one of the memory sub-arrays, the set of concurrent instructions arranged in sequential order from a first instruction to a last instruction

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Round Rock, TX, United States of America

Jafar Nahidi