Devices and techniques for low-latency register error correction are described herein. A register is read as part of an instruction when that instruction is the currently executing instruction in a processor. A correctable error in data produced from reading the register can be detected. In response to detecting the correctable error, the currently executing instruction in the processor can be changed into a register update instruction that is executed to overwrite the data in the register with corrected data. Then, the original (e.g., unchanged) instruction can be rescheduled.

A multi-thread synchronization method includes that a first thread requests to obtain a target lock. Then, the first thread checks the lock thread identifier field. The first thread checks the blocked thread quantity field when checking that the lock thread identifier field is a valid thread and is not the first thread. The first thread performs spin wait when checking that the blocked thread quantity field is less than a first threshold. When a quantity of times for spin wait reaches a second threshold and when it is checked that the lock thread identifier field is the valid thread and is not the first thread, the first thread performs an operation of adding 1 to the blocked thread quantity field, and suspends to enter a blocked state.

A predicated-loop-terminating branch instruction controls, based on whether a loop termination condition is satisfied, whether the processing circuitry should process a further iteration of a predicated loop body or process a following instruction. If at least one unnecessary iteration of the predicated loop body is processed following a mispredicted-non-termination branch misprediction when the loop termination condition is mispredicted as unsatisfied for a given iteration when it should have been satisfied, processing of the at least one unnecessary iteration of the predicated loop body is predicated to suppress an effect of the at least one unnecessary iteration. When the mispredicted-non-termination branch misprediction is detected for the given iteration of the predicated-loop-terminating branch instruction, in response to determining that a flush suppressing condition is satisfied, flushing of the at least one unnecessary iteration of the predicated loop body is suppressed as a response to the mispredicted-non-termination branch misprediction.

A split level history buffer in a central processing unit is provided. A first instruction and a second instruction are fetched, tagged, and the first instruction is stored an entry of a register file. The first instruction is evicted from the entry and the second instruction is stored in the entry. If the first instruction is evicted, then the first instruction is stored in a first portion of a history buffer. If a result for the first instruction is generated, then the first instruction is moved to a second portion of the history buffer and the result is stored with the first instruction in the second portion of the history buffer. If it is determined that a third instruction evicts the second instruction from the entry, then the second instruction is stored in the first portion of the history buffer.

Apparatus and methods are disclosed for controlling execution of memory access instructions in a block-based processor architecture using a hardware structure that indicates a relative ordering of memory access instruction in an instruction block. In one example of the disclosed technology, a method of executing an instruction block having a plurality of memory load and/or memory store instructions includes selecting a next memory load or memory store instruction to execute based on dependencies encoded within the block, and on a store vector that stores data indicating which memory load and memory store instructions in the instruction block have executed. The store vector can be masked using a store mask. The store mask can be generated when decoding the instruction block, or copied from an instruction block header. Based on the encoded dependencies and the masked store vector, the next instruction can issue when its dependencies are available.

Certain embodiments of the present disclosure support a method and apparatus for efficient multithreading on a single core microprocessor. Thread switching in the single core microprocessor presented herein is based on a reserved space in a memory allocated to each thread for storing and restoring of registers in a register file. The thread switching is achieved without full save and restore of the register file, and only those registers referenced in the memory are saved and restored during thread switching.

A data processing apparatus, and method of operation thereof, for executing instructions. The apparatus includes one or more host processors, each having a first processing unit, and a multi-level memory system. One or more levels of the memory system are tightly coupled to a corresponding second processing unit. At least one of the host processors includes an instruction scheduler that routes instructions selectively to at least one of the first and second processing units, dependent upon the availability of the processing units and the location, within the memory system, of data to be used when executing the instructions.

In a multi-processor transaction execution environment, a transaction executes a hint instruction indicating proximity to completion of the transaction. Pending aborts of the transaction due to memory conflicts are suppressed based on the proximity of the transaction to completion.

To implement low-latency register error correction a register may be read as part of an instruction when that instruction is the currently executing instruction in a processor. A correctable error in data produced from reading the register can be detected. In response to detecting the correctable error, the currently executing instruction in the processor can be changed into a register update instruction that is executed to overwrite the data in the register with corrected data. Then, the original (e.g., unchanged) instruction can be rescheduled.

The invention introduces an apparatus for segmenting a data stream, installed in a physical layer, to include a host interface, a data register and a boundary detector. The data register is arranged to operably store data received from the host side through the host interface. The boundary detector is arranged to operably detect the content of a data register. When the data register includes a special symbol, the boundary detector outputs a starting address that the special symbol is stored in the data register to an offset register to update a value stored in the offset register, thereby enabling a stream splitter to divide data bits of the data register according to the updated value of the offset register.