Abstract: In a processor that executes complex instructions which are expanded into microinstructions prior to execution, non-complex instruction execution is optimized by providing a by-passable helper logic for expanding complex instructions into microinstructions. Control logic parses a bundle of instructions into sub-bundles of non-complex instructions and sub-bundles of microinstructions. The control logic detects when a complex instruction is present in a bundle of instructions and directs the complex instruction to the helper logic for expansion into two or more microinstructions. Each non-complex instruction bypasses the helper logic, thereby improving the execution performance of the non-complex instruction.

Abstract: In a processor speculatively executing instructions which specify logical addresses, a method and apparatus for speculatively converting logical addresses to physical addresses. The processor has a register window movable within a register file, a window pointer register maintaining a value corresponding to the location of the window in the register file, a speculative window pointer register maintaining a speculative value of the window pointer register. A controller identifies an instruction expected to modify the value in the window pointer register, and in response to identifying the instruction the controller modifies the speculative value. A mapper, coupled to the speculative window pointer register, converts the instruction specified logical addresses to physical addresses based on the speculative value contained in the speculative window pointer register.

Abstract: A method and apparatus for tracking pipeline resources of a processor involves fetching selected ones of the coded instructions and marking the fetched instructions with instruction metadata. The instruction metadata indicates a number of pipeline resources required by each instruction. The marked instructions are issued from the fetch unit and, using the instruction metadata, a count of a number of resources committed to issued instructions in the execution pipelines is maintained. When it is determined that the number of resources committed to issued instructions exceeds a preselected maximum and instructions are prevented from issuing from the fetch unit. As each instruction is retired, the instruction metadata is used to determine a number of resources released by retirement of the issued instruction.

Abstract: A cache memory array stores two-way set associative data. An odd set data bank stores odd number sets of the two-way set associative data, where the two ways of each odd number set are aligned horizontally within the odd set data bank. An even set data bank stores even number sets of the two-way set associative data, where the two ways of each even number set are aligned horizontally within the even set data bank. Also, the odd set data bank is aligned horizontally with the even set data bank such that each odd number set is aligned horizontally with a next even number set. The horizontally aligned ways are interleaved for data path width reduction. Set and way selection circuits extract lines of data from the array. The array may be structurally implemented by single-ported RAM cells.

Abstract: In a processor executing instructions speculatively or out-of-order, a dependency table tracks instruction dependencies between a current instruction and a live instruction. The table contains an instruction identifier and the destination register specified by the live instruction. The table can also contain information about the age of the entry, the validity of the entry, and the process which the entry is associated. A dependency between instructions is determined by one or more comparators comparing the destination register to the source registers of the current instruction. True dependencies are distinguished from false dependencies using the age information, the validity information, and the process information.

Abstract: A processor including at least one execution unit generating out-of-order results and out-of-order condition codes. Precise architectural state of the processor is maintained by providing a results buffer having a number of slots and providing a condition code buffer having the same number of slots as the results buffer, each slot in the condition code buffer in one-to-one correspondence with a slot in the results buffer. Each live instruction in the processor is assigned a slot in the results buffer and the condition code buffer. Each speculative result produced by the execution units is stored in the assigned slot in the results buffer. When an instruction is retired, the results for that instruction are transferred to an architectural result register and any condition codes generated by that instruction are transferred to an architectural condition code register.