摘要:
A method, apparatus and computer instructions are provided to autonomically monitor and adjust system characteristics based on a customer optimization goal specified in a policy or profile. An autonomic management component is implemented in firmware comprising a set of control algorithms. Response to reading system characteristics from a plurality of sensors, the autononmic management component selects at least one control algorithm from the set and the control algorithm adjusts the parameters of the system characteristic to optimize performance according to the optimization goal specified by the customer.
摘要:
A method, apparatus, and computer program product are disclosed for selectively prohibiting speculative conditional branch execution. A particular type of conditional branch instruction is selected. An indication is stored within each instruction that is the particular type of conditional branch instruction. A processor then fetches a first instruction from code that is to be executed. A determination is made regarding whether the first instruction includes the indication. In response to determining that the instruction includes the indication: speculative execution of the first instruction is prohibited, an actual location to which the first instruction will branch is resolved, and execution of the code is branched to the actual location. In response to determining that the instruction does not include the indication, the first instruction is speculatively executed.
摘要:
A mechanism structured to check for instruction collisions at the Dispatch Unit rather than the Completion Unit. In processors which issue multiple commands simultaneously, a flag bit is sent to the Completion Unit and attached to the instruction in the queue that follows the other in program order if they both have the same targeted address. When the instructions from position 1 and position 2 of the instruction queue are ready to issue, the Completion Unit checks position 2 for a flag bit. If there is a bit, then the instruction in position 1 is discarded and the instruction in position 2 is written to the target address. If there is no flag bit with the instruction in position 2, the instruction in position 1 is written to the target register. This method eliminates the need to compare all the targeted addresses that are associated with the rename registers. It requires two comparisons instead of a minimum of 15 comparisons.
摘要:
An apparatus and method for executing a Load Register instruction in which the source data of the Load Register instruction is retained in its original physical register while the architected target register is mapped to this same physical target register. In this state the two architected registers alias to one physical register. When the source register of the Load Address instruction is specified as the target address of a subsequent instruction, a free physical register is assigned to the Load Registers source register. And with this assignment the alias is thus broken. Similarly when the target register of the Load Address instruction is the target address of a subsequent instruction, a new physical register is assigned to the Load Registers target address. And with this assignment the alias is thus broken.
摘要:
An apparatus and method for executing a Load Register instruction in which the source data of the Load Register instruction is retained in its original physical register while the architected target register is mapped to this same physical target register. In this state the two architected registers alias to one physical register. When the source register of the Load Address instruction is specified as the target address of a subsequent instruction, a free physical register is assigned to the Load Registers source register. And with this assignment the alias is thus broken. Similarly when the target register of the Load Address instruction is the target address of a subsequent instruction, a new physical register is assigned to the Load Registers target address. And with this assignment the alias is thus broken.
摘要:
An XER scoreboard function is provided by utilizing the instruction sequencer unit scoreboard. A scoreboard bit is set if the XER is being used by a previous instruction. If a new instruction is fetched that uses the XER, a dummy read to the XER is generated to test the scoreboard bit to determine if the scoreboard bit is set. If the scoreboard bit is not set when the dummy read is executed, the X-form string proceeds to execution. If the scoreboard bit is set when the dummy is executed, the pipeline is stalled until the scoreboard bit is cleared, and then the X-form string padded with generated padding IOPs (Dummy or NOPs) is executed. After an accessing instruction is executed, the scoreboard bit is cleared.
摘要:
A “soft-patch” allows an instruction or group of instructions to be replaced with a pre-loaded instruction or group of instructions. When an Instruction Fetch Unit (IFU) fetches an instruction, the instruction is sent through a Compare and Mask (CAM) circuit which masks and compares, in parallel, the instruction with up to eight pre-defined masks and values. The masks and values are pre-loaded by a service processor to CAM circuits which are located in an Instruction Dispatch Unit (IDU) and the IFU in the central processor. An instruction that is deemed a match, is tagged by the IFU as a “soft-microcode” instruction. When the IDU receives the soft-microcode instruction for decoding, it detects the soft microcode marking and sends the marked instruction to a soft-microcode unit; a separate parallel pipeline in the IDU. The soft-microcode unit then sends the instruction through a CAM circuit which returns an index (or address) for RAM. The index is used to read values out of IDU RAM and generate replacement instructions. Additionally, an Internal Operation that will cause the processor core to perform an unconditional branch to a fixed real address, can be loaded into the IDU RAM allowing an instruction to be replaced by a subroutine or handler routine contained outside the processor core.
摘要:
A generalized, programmable dataflow state-machine is provided to receive information about a particular string instruction. The string instruction is parsed into all the operations contained in the string instruction. The operations that make up the string instruction are routed to parallel functional units and executed. The state-machine manipulates the size of the operations in the string instruction and whether or not the instructions need to be generated.
摘要:
A method of performing operations to a link stack including the step of performing a Pop operation from the link stack which includes the substeps of storing a first pointer value to the link stack, the first pointer value being the value of a pointer to the link stack before the Pop operation, and storing a first address including a first tag popped from the link stack. The method further includes the step of performing a Push operation to the link stack which includes the substeps of storing a second address including a second tag being Pushed into the link stack and storing a second pointer to the link stack, the second pointer being the value of the pointer to the link stack after the Push operation. The method additionally provides for the recovering of the link stack following an instruction flush which includes the substeps of comparing the first pointer value and the second value, comparing the first tag and the second tag, and replacing an address at the top of the link stack with the first address when the first and second pointers match and the first and second tags match.
摘要:
A dummy instruction is issued, followed by several groups of No Operations (NOPs). The instruction sequencer unit (ISU) detects the dummy instruction and stalls the pipeline until the scoreboard indicates the XER count is valid. After a read from a scoreboarded Special Purpose Register (SPR), No Operation—Internal Operations (NOP—IOPs) are inserted between write and read SPR IOPs to allow an ISU scoreboard mechanism to be activated before being tested by a read SPR IOP. A read-write-read sequence is utilized: a dummy read of the string count field from a scoreboarded SPR, writing that value back to the same SPR and then performing a read of the SPR once again. A predetermined number of dummy IOPs follow the initial dummy read to prevent the value of the string count field from being read too soon.