Abstract: A design structure embodied in a machine readable storage medium for designing, manufacturing, and/or testing a design for a single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines is provided. A mechanism is described for indexing into the cache, and selecting the desired line. Control is exercised over which lines are contained within the cache. Provision is made for selection between a trace line and a conventional line when both match during a tag compare step.

Abstract: A single unified level one instruction(s) cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instruction(s) consistent with conventional cache lines. Formation of trace lines in the cache is delayed on initial operation of the system to assure quality of the trace lines stored.

Abstract: A single unified level one instruction(s) cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instruction(s) consistent with conventional cache lines. Formation of trace lines in the cache is delayed on initial operation of the system to assure quality of the trace lines stored.

Abstract: A single unified level one instruction(s) cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instruction(s) consistent with conventional cache lines. Formation of trace lines in the cache is delayed on initial operation of the system to assure quality of the trace lines stored.

Abstract: A single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines. A mechanism is described for indexing into the cache, and selecting the desired line. Control is exercised over which lines are contained within the cache. Provision is made for selection between a trace line and a conventional line when both match during a tag compare step.

Abstract: A single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines. Power is conserved by guiding access to lines stored in the cache and lowering cache clock speed relative to the central processor clock speed.

Abstract: A single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines. Control is exercised over which lines are contained within the cache. This invention avoids inefficiencies in the cache by removing trace lines experiencing early exits from the cache, or trace lines that are short, by maintaining a few bits of information about the accuracy of the control flow in a trace cache line and using that information in addition to the LRU (Least Recently Used) bits that maintain the recency information of a cache line, in order to make a replacement decision.

Abstract: A design structure embodied in a machine readable storage medium for designing, manufacturing, and/or testing a design for a single unified level one instruction(s) cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instruction(s) consistent with conventional cache lines is provided. Formation of trace lines in the cache is delayed on initial operation of the system to assure quality of the trace lines stored.

Abstract: A design structure embodied in a machine readable storage medium for designing, manufacturing, and/or testing a design for a single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines is provided. A mechanism is described for indexing into the cache, and selecting the desired line. Control is exercised over which lines are contained within the cache. Provision is made for selection between a trace line and a conventional line when both match during a tag compare step.

Abstract: A design structure embodied in a machine readable storage medium for at least one of designing, manufacturing, and testing a design for a single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines is provided. Instruction branches are predicted taken or not taken using a highly accurate branch history table (BHT). Branches that are predicted not taken are appended to a trace buffer and the next basic block is constructed from the remaining instructions in the fetch buffer. Branches that are predicted taken flush the remaining fetch buffer and the next address is determined using a Branch Target Address Register (BTAC).

Abstract: A design structure embodied in a machine readable storage medium for at least one of designing, manufacturing, and testing a design for register renaming allows processor hardware to use a larger set of registers than the architected registers visible to the compiler. This larger set of registers is called the physical register file. Thus, dynamically renaming every compiler-suggested architected register to a microarchitecture-specific physical register, allows the processor to overcome name dependencies and the hazards (pipeline slowdowns) induced by name dependencies.

Abstract: A single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines. Instruction branches are predicted taken or not taken using a highly accurate branch history table (BHT). Branches that are predicted not taken are appended to a trace buffer and the next basic block is constructed from the remaining instructions in the fetch buffer. Branches that are predicted taken flush the remaining fetch buffer and the next address is determined using a Branch Target Address Register (BTAC).

Abstract: A single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines. Control is exercised over which lines are contained within the cache. This invention avoids inefficiencies in the cache by removing trace lines experiencing early exits from the cache, or trace lines that are short, by maintaining a few bits of information about the accuracy of the control flow in a trace cache line and using that information in addition to the LRU (Least Recently Used) bits that maintain the recency information of a cache line, in order to make a replacement decision.

Abstract: A single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines. Power is conserved by guiding access to lines stored in the cache and lowering cache clock speed relative to the central processor clock speed.

Abstract: A single unified level one instruction(s) cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instruction(s) consistent with conventional cache lines. Formation of trace lines in the cache is delayed on initial operation of the system to assure quality of the trace lines stored.

Abstract: A single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines. A mechanism is described for indexing into the cache, and selecting the desired line. Control is exercised over which lines are contained within the cache. Provision is made for selection between a trace line and a conventional line when both match during a tag compare step.

Abstract: Register renaming as contemplated by this invention allows processor hardware to use a larger set of registers than the architected registers visible to the compiler. This larger set of registers is called the physical register file. Thus, dynamically renaming every compiler-suggested architected register to a microarchitecture-specific physical register, allows the processor to overcome name dependencies and the hazards (pipeline slowdowns) induced by name dependencies. The invention here described differs from prior renaming techniques in that it extracts significant benefit from renaming with a fraction of the number of physical registers previously used for this process. The invention therefore also simplifies the logic involved in supporting the use of the physical registers.

Abstract: An electronic switching and data transmission system for interconnecting a plurality of buses. A switching network interconnects several multi-drop buses using adapters to connect the buses to the switching network. The adapters implements hardware functions to appear to software as if all devices on the several buses were attached to a single large bus. The system permits higher speed transfer modes by eliminating multi-drop bus limitations.

Abstract: A checkpoint retry system for recovery from an error condition in a multiprocessor type central processing unit which may have a store-in or a store-through cache system. At detection of a checkpoint instruction, the system initiates action to save the content of the program status word, the floating point registers, the access registers and the general purpose registers until the store operations are completed for the checkpointed sequence. For processors which have a store-in cache, modified cache data is saved in a store buffer until the checkpointed instructions are completed and then written to a cache which is accessible to other processors in the system. For processors which utilize store-through cache, the modified data for the checkpointed instructions is also stored in the store buffer prior to storage in the system memory.

Abstract: A broadcast/switching apparatus makes input port to output port connections on a requested basis quickly and dynamically in a standard mode from any one of the input ports to any one of the output ports, in a multi-cast mode from any one of the input ports to a fixed number of subsets of multiple output ports simultaneously, or in a broadcast mode from any one of the input ports to all output ports simultaneously, using a new asynchronous approach to resolve either broadcast or multi-cast contention among input ports. The normal mode of the broadcast/switch apparatus requires absolutely no synchronization among any of the input and output ports which interface to the apparatus. The broadcast/switch apparatus also incorporates a new accept protocol that enables a positive feedback indication to be returned to the sender of a multi-cast or broadcast operation to inform it that the multi-cast or broadcast transmission was correctly received by all elements involved in the multi-cast or broadcast.