Abstract: A multibit combined multiplexer and flip-flop circuit has a plurality of bit circuits. Each bit circuit includes and input section, a flip-flop section and a per bit control section. The input sections have inputs for plural of input signals and corresponding input pass gates. The outputs of the input pass gates are connected to the input of the flip-flop section. Each per bit control section includes an inverter for each input terminal. There is a combined control section receiving a clock signal and a control signals for selection of only one of the input signals. The combined control section include a logical AND for each input signal combining the clock signal and the selection signal. The output of each logical AND is connected to the input of a corresponding inverter of each per bit control circuit. The input pass gate are controlled by a corresponding logical AND and said corresponding inverter.

Abstract: A system for prefetching memory in caching systems includes a processor that generates requests for data. A cache of a first level stores memory lines retrieved from a lower level memory in response to references to addresses generated by the processor's requests for data. A prefetch buffer is used to prefetch an adjacent memory line from the lower level memory in response to a request for data. The adjacent memory line is a memory line that is adjacent to a first memory line that is associated with an address of the request for data. An indication that a memory line associated with an address associated with the requested data has been prefetched is stored. A prefetched memory line is transferred to the cache of the first level in response to the stored indication that a memory line associated with an address associated with the requested data has been prefetched.

Abstract: A predictive adder produces the result of incrementing and/or decrementing a sum of A and B by a one-bit constant of the form of the form 2k, where k is a bit position at which the sum is to be incremented or decremented. The predictive adder predicts the ripple portion of bits in the potential sum of the first operand A and the second operand B that would be toggled by incrementing or decrementing the sum A+B by the one-bit constant to generate and indication of the ripple portion of bits in the potential sum. The predictive adder uses the indication of the ripple portion of bits in the potential sum and the carry output generated by evaluating A+B to produce the results of at least one of A+B+2k and A+B?2k.

Abstract: Multiprocessor systems often share access to a centralized memory and experience conflicting access requests. An arbitration unit mediates priorities of requestor preferably ensuring both priority and fairness. In this invention upon an access conflict the arbitrator grants access to one requestor having the highest priority level and stalls other conflicting requestors. If plural requestors have the same priority level, the arbiter grants access to one and stalls the others. The arbiter then adjusts the priority levels of the requestors. The priority of the requestor granted access is decreased by the number of stalled requestors. The stalled requestors have their priority levels increased by one. The arbitration decision is thus based on the stall history and the caused stall history of each requestor.

Abstract: A heat exchanger including a primary inlet manifold that has an inlet port to receive refrigerant from a source, a primary outlet manifold that has an outlet port to discharge refrigerant from the heat exchanger, and a plurality of microchannel tubes fluidly connected between the primary inlet manifold and the primary outlet manifold and spaced apart from each other. Each of the plurality of microchannel tubes has a secondary inlet manifold fluidly coupled to the primary inlet manifold, a secondary outlet manifold fluidly coupled to the primary outlet manifold, and at least one microchannel fluidly coupled between the secondary inlet manifold and the secondary outlet manifold to direct refrigerant to the secondary outlet manifold. The heat exchanger also includes a plurality of fins disposed between adjacent microchannel tubes and oriented to define an airflow path along the longitudinal direction of the microchannel tubes.

Abstract: A merchandiser including a case defining a product display area and having case structure. The merchandiser also includes a light assembly. The light assembly has a light housing and a light source coupled to the light housing to direct light generally toward the product display area. The merchandiser further includes an attachment mechanism having a magnet housing and a magnet substantially enclosed by the magnet housing. The attachment mechanism is coupled to the light housing opposite the light source to attach the light assembly to the case structure.

Abstract: A memory management and protection system that manages memory access requests from a number of requestors. Memory accesses are allowed or disallowed based on the privilege level of the requestor, based on a Privilege Identifier that accompanies each memory access request. An extended memory controller selects the appropriate set of segment registers based on the Privilege Identifier to insure that the request is compared to and translated by the segment register associated with the requestor originating the request. A set of mapping registers allow flexible mapping of each Privilege Identifier to the appropriate access permission. The segment registers translate the logical address from the requestor to a physical address within a larger address space.

Abstract: A processor includes a shift overflow detector for rapidly detecting overflows that may result during execution of a shift instruction. Shift indication signals are generated in response to changes in logic state between adjacent pairs of bits of a received shift data word. A received shift amount is decoded to produce decoded shift signals that indicate an amount of shifting for the received shift data word. An overflow condition is detected in response to the generated shift indication signals and the decoded shift signals and an indication of the detected overflow condition is provided.

Abstract: A processor includes a first and second execution unit each of which is arranged to execute multiply instructions of a first type upon fixed point operands and to execute multiply instructions of a second type upon floating point operands. A register file of the processor stores operands in registers that are each addressable by instructions for performing the first and second types of operations. An instruction decode unit is responsive to the at least one multiply instruction of the first type and the at least one multiply instruction of the second type to at the same time enable a first data path between the first set of registers and the first execution unit and to enable a second data path between a second set of registers and the second execution unit.

Abstract: A processor includes a two's complement arithmetic unit that reduces a level of complexity in the critical path by eliminating the addition of the “1” to the carry in of the two's complement arithmetic unit. To execute a subtraction instruction using two's complement arithmetic, the subtraction as disclosed herein is performed in accordance with the identity “A?B=not (not (A)+B),” where A is a first operand and B is a second operand that is to be subtracted from A. Accordingly, the addition of the “1” term into the carry in is eliminated, and reduces a level of complexity that would otherwise slow down and/or limit the speed at which a subtraction instruction can be performed.

Abstract: A prefetch unit generates prefetch addresses in response to an initial received memory read request, an address associated with the initial received memory read request, a line length of the requestor of the initial received memory read request, and a request type width of the initial received memory read request. Prefetch operations are generated using the generated prefetch addresses, wherein each generated prefetch address is stored in a prefetch buffer slot that is selected by a prefetch FIFO (First In First Out) prefetch counter. Subsequent hits on the prefetcher result in returning prefetched data to the requestor in response to a subsequent memory read request received after the initial received memory read request.

Abstract: A prefetch unit receives a memory read request having an associated address for accessing data that is stored in memory. A next predicted address is determined in response to a prefetch address stored in a slot of an array for storing portions of predicted addresses and associated with a slot in accordance with an order in which a prefetch FIFO counter is modified to select the slots of the array. Data is prefetched from a lower-level hierarchical memory in accordance with a next predicted address and provisioned the prefetched data to minimize a read time for reading the prefetched data. The provisioned prefetched data is read-out when the address of the memory request is associated with the next predicted address.

Abstract: A memory arbiter minimizes latency of memory accesses in a system having multiple processors. The memory arbiter improves overall system performance by managing the memory requests from each processor individually before those requests are sent to a central memory arbiter for handling memory requests for the shared resources from the multiple processors. The local memory arbiter buffers the memory requests from a local processor, analyzes the buffered memory requests, and optimizes the requests by reordering commands according to a rule set, and by performing write merging and prefetch squashing in certain conditions.

Abstract: An arbiter is provided for arbitrating for access to a shared resource by a plurality of requesters and by a background requester in a processing system. A priority value is assigned to each of the plurality of requestors. A multilayer arbitration contest is performed to resolve each conflict in transaction requests to the shared resource, however, a requester of the plurality of requesters having a highest priority value does not always win an arbitration contest. An arbitration contest will be overridden whenever the background requester initiates a transaction request, such that the background requester always wins the overridden arbitration contest. The shared resource is accessed by the winner of each arbitration contest.

Abstract: A memory validation manager reserves a block of time for exclusive accesses to a memory bank having lines of memory for which validation codes provide a degree of error detection and correction for each memory line. The memory validation manager reads, processes, and corrects at least some of the contents of each memory line based on indications of validity encountered for each memory line. New data is written in response to a validation code. Likewise, a valid field for each line can be updated and a new validation code written for a memory when the valid field indicates that a validation code has not yet been written for a memory line. The memory validation manager processes data read from a first memory line while either reading or writing to another memory line to minimize the latency of the process of scrubbing memory lines.

Abstract: A prefetch filter receives a memory read request having an associated address for accessing data that is stored in a line of memory. An address window is determined that has an address range that encompasses an address space that is twice as large as the line of memory. In response to a determination of in which half the address window includes the requested line of memory, a prefetch direction is to a first direction or to an opposite direction. The prefetch filter can include an array of slots for storing a portion of a next predicted access and determine a memory stream in response to a hit on the array by a subsequent memory request. The prefetch filter FIFO counter cycles through the slots of the array before wrapping around to a first slot of the array for storing a next predicted address portion.

Abstract: A prefetch cancelation arbiter improves access to a shared memory resource by arbitrarily canceling speculative prefetches. The prefetch cancelation arbiter applies a set of arbitrary policies to speculative prefetches to select one or more of the received speculative prefetches to cancel. The selected speculative prefetches are canceled and a cancelation notification of each canceled speculative prefetch is sent to a higher-level memory component such as a prefetch unit or a local memory arbiter that is local to the processor associated with the canceled speculative prefetch. The set of arbitrary policies is used to reduce memory accesses to the shared memory resource.

Abstract: The core of this invention is the application of a fast comparison circuit to the problem of address translation. Traditional implementations generate the virtual address and the physical address in series. This invention generates the physical address and virtual address simultaneously. A bitwise operation on the base address, the offset address and each stored virtual address determines whether the base address and offset address sum equals the virtual address without requiring a carry propagate. Circular addressing is implemented in the match determination by masking bits corresponding to the circular address limit.

Abstract: A system for prefetching memory in caching systems includes a processor that generates requests for data. A cache of a first level stores memory lines retrieved from a lower level memory in response to references to addresses generated by the processor's requests for data. A prefetch buffer is used to prefetch an adjacent memory line from the lower level memory in response to a request for data. The adjacent memory line is a memory line that is adjacent to a first memory line that is associated with an address of the request for data. An indication that a memory line associated with an address associated with the requested data has been prefetched is stored. A prefetched memory line is transferred to the cache of the first level in response to the stored indication that a memory line associated with an address associated with the requested data has been prefetched.

Abstract: A processor includes a shift device for extending the width of a rotator without increasing propagation delays. An extended-width result is obtained by combining a rotation result with a shift result in accordance with a mask that is selected in response to at least a portion of the value of the degree to which a data word is to be shifted.