Abstract: A residue-based error checking mechanism is provided for checking for error in a shift operation of a shifter. The checking includes: partitioning an input vector into the shifter into one or more bit groups of bit width W; generating a predicted residue on the input vector being shifted, the generating including masking out any bit group of bit width W fully shifted out by the shift operation from contributing to the predicted residue, and the generating accounting for any bits of a bit group of the input vector partially shifted out by the shift operation; generating a result residue on a result vector of the shift operation; and comparing the result residue with the predicted residue to check for an error in the result vector of the shift operation.

Abstract: Embodiments are directed to a computer implemented method for executing machine instructions in a central processing unit. The executing includes loading a first operand into a first operand register, and loading a second operand into a second operand register. The executing further includes shifting either the first operand or the second operand to form a shifted operand. The executing further includes adding or subtracting the first operand and the second operand to obtain a sum or a difference, and loading the sum or the difference having a least significant bit into a third register or a memory. The executing further includes performing a probability analysis on least significant bits of the shifted operand or the non-shifted operand, and initiating a rounding operation on the least significant bit of the sum or the difference based at least in part on the probability analysis.

Abstract: Embodiments are directed to a computer implemented method for executing machine instructions in a central processing unit. The method includes obtaining, by a processor system, a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture. The method further includes executing the machine instruction, wherein the executing includes loading a multiplicand into a multiplicand register, and loading a multiplier into a multiplier register. The executing further generates an intermediate product having least significant bits by multiplying the multiplicand and the multiplier. The executing further includes generating a rounded product by performing a probability analysis on the least significant bits of the intermediate product, and initiating a rounding operation on the intermediate product to produce the rounded product based at least in part on the probability analysis.

Abstract: Embodiments are directed to a computer implemented method for executing machine instructions in a central processing unit. The method includes obtaining, by a processor system, a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture. The method further includes executing the machine instruction, wherein the executing includes loading a multiplicand into a multiplicand register, and loading a multiplier into a multiplier register. The executing further generates an intermediate product having least significant bits by multiplying the multiplicand and the multiplier. The executing further includes generating a rounded product by performing a probability analysis on the least significant bits of the intermediate product, and initiating a rounding operation on the intermediate product to produce the rounded product based at least in part on the probability analysis.

Abstract: Embodiments are directed to a computer implemented method for executing machine instructions in a central processing unit. The executing includes loading a first operand into a first operand register, and loading a second operand into a second operand register. The executing further includes shifting either the first operand or the second operand to form a shifted operand. The executing further includes adding or subtracting the first operand and the second operand to obtain a sum or a difference, and loading the sum or the difference having a least significant bit into a third register or a memory. The executing further includes performing a probability analysis on least significant bits of the shifted operand or the non-shifted operand, and initiating a rounding operation on the least significant bit of the sum or the difference based at least in part on the probability analysis.

Abstract: A method for implementing a programmable linear feedback shift register instruction, the method includes obtaining, by a processor, the machine instruction for execution, the machine instruction includes a first input operand indicating the current value of a shift register, wherein the shift register includes a data bit for each of a plurality of cells, a second input operand indicating a first sub-set of cells from the plurality of cells, and a logical operation specifier field indicating a logical operation to perform on the first and second input operands. Additionally, executing the machine instruction includes performing the logical operation based on the first input operand, the second input operand, and the logical operation specifier field, and generating an output operand by shifting the current value of the shift register to vacate a cell of the shift register and inserting an output value of the logical operation into the vacated cell of the shift register.

Abstract: A method for implementing a programmable linear feedback shift register instruction, the method includes obtaining, by a processor, the machine instruction for execution, the machine instruction includes a first input operand indicating the current value of a shift register, wherein the shift register includes a data bit for each of a plurality of cells, a second input operand indicating a first sub-set of cells from the plurality of cells, and a logical operation specifier field indicating a logical operation to perform on the first and second input operands. Additionally, executing the machine instruction includes performing the logical operation based on the first input operand, the second input operand, and the logical operation specifier field, and generating an output operand by shifting the current value of the shift register to vacate a cell of the shift register and inserting an output value of the logical operation into the vacated cell of the shift register.

Abstract: The disclosed herein related to a method for generating a partial stochastic rounding operation executed by a processor coupled to a memory. The method includes generating an intermediate result and causing a random number generator to generate a random number. The method also includes adding the random number to lower significant bits of the intermediate result to perturb any incrementing of most significant bits of the intermediate result to produce a resulting sum. The method also includes truncating the resulting sum into a final result. According to other embodiments, the above method can be implemented in a system or computer program product.

Abstract: A method for generating a random number for use in a stochastic rounding operation is provided. The method includes executing an instruction that causes at least two operands to produce an intermediate result and incrementing a state of a random number generator. The method d further includes causing the random number generator to generate a random number in accordance with the state and producing a final result by utilizing the random number to determine a rounding of the intermediate result.

Abstract: A method for delocalizing an error checking on a data in a pipelined processor from the data checked. A first check-data is generated at a first location on a first data. A second location receives the first data and the first check-data. A second check-data is generated on the first data and the first check-data is compared with the second check-data at the second location. A second data is generated from the first data and a third check-data is generated on the second data at the second location. A third check-data is generated on the second data at the second location and the second data is transferred to a third location. The third check-data is transferred to a fourth location. A fourth check-data is generated on the second data and is transferred to the fourth location. The fourth check-data and the third check-data are compared at the fourth location.

Abstract: A condition code can depend upon a numerical output of a floating point operation for a processing pipeline. A classification can be determined for the floating point operation of a received instruction. In response to the classification and using condition determination logic, a value can be calculated for the condition code by inferring from data that is available from the processing pipeline before the numerical output is available. The value for the condition code can be provided to branch decision logic of the processing pipeline.

Abstract: A condition code can depend upon a numerical output of a floating point operation for a processing pipeline. A classification can be determined for the floating point operation of a received instruction. In response to the classification and using condition determination logic, a value can be calculated for the condition code by inferring from data that is available from the processing pipeline before the numerical output is available. The value for the condition code can be provided to branch decision logic of the processing pipeline.

Abstract: Arithmetic logic circuitry is provided for performing a floating point arithmetic add/subtract operation on first and second floating point numbers. The method includes: generating a guard digit for the first or second number by transforming the first and second numbers by a compressing function; determining a result depending on the arithmetic operation, a sum of the transformed floating point numbers, and first and second differences of the transformed floating point numbers, and determining a corresponding result plus one by additionally adding a value of one to the result; generating injection values for rounding the final result; generating injection carry values based on the transformed first and second numbers and the injection values; and selecting the final result from the result, the result plus one, and a least significant digit, based on the injection carry values and the end around carry signals.

Abstract: Embodiments include a method for temporary pipeline marking for processor error workarounds. The method includes monitoring an execution unit pipeline of a processor for an event associated with a programmable instruction operational code that is predetermined to cause a stuck state resulting in an errant instruction execution. The execution unit pipeline is marked for a workaround action based on detecting the event. A clearing action is triggered based on the marking, where the triggering is conditionally triggered by a next instruction in the execution unit pipeline having a same instruction type as the programmable instruction operational code. The marking of the pipeline is cleared based on the triggering of the clearing action, where the clearing action is a subsequent pipeline flush event based on the next instruction having the same instruction type reaching a same pipeline stage that results in a stuck state prior to completion of the next instruction.

Abstract: A system includes a set-associative storage container and a processor configured to generate a vector that is a random number. Two or more residue functions are applied to the vector that each produces a state signal including a different number of states based on the vector. A set status is determined that identifies whether each set of the set-associative storage container is enabled or disabled. One of the state signals is selected that has a same number of states as a number of the sets that are enabled. The selected state signal is mapped to the sets that are enabled to assign each of the states of the selected state signal to a corresponding one of the sets that are enabled. A set selection of the set-associative storage container is output based on the mapping to randomly select one of the sets that are enabled from the set-associative storage container.

Abstract: Arithmetic logic circuitry is provided for performing a floating point arithmetic add/subtract operation on first and second floating point numbers. The method includes: generating a guard digit for the first or second number by transforming the first and second numbers by a compressing function; determining a result depending on the arithmetic operation, a sum of the transformed floating point numbers, and first and second differences of the transformed floating point numbers, and determining a corresponding result plus one by additionally adding a value of one to the result; generating injection values for rounding the final result; generating injection carry values based on the transformed first and second numbers and the injection values; and selecting the final result from the result, the result plus one, and a least significant digit, based on the injection carry values and the end around carry signals.

Abstract: Resources in a computing environment are managed, for example, by a hardware controller controlling dispatching of resources from one or more pools of resources to be used in execution of threads. The controlling includes conditionally dispatching resources from the pool(s) to one or more low-priority threads of the computing environment based on current usage of resources in the pool(s) relative to an associated resource usage threshold. The management further includes monitoring resource dispatching from the pool(s) to one or more high-priority threads of the computing environment, and based on the monitoring, dynamically adjusting the resource usage threshold used in the conditionally dispatching of resources from the pool(s) to the low-priority thread(s).

Abstract: Embodiments include a method for temporary pipeline marking for processor error workarounds. The method includes monitoring a pipeline of a processor for an event that is predetermined to place the processor in a stuck state that results in an errant instruction execution result due to the stuck state or repeated resource contention causing performance degradation. The pipeline is marked for a workaround action based on detecting the event. A clearing action is triggered based on the marking of the pipeline. The marking of the pipeline is cleared based on the triggering of the clearing action.

Abstract: A computer-implemented method includes generating a vector that is a random number. Two or more residue functions are applied to the vector to produce a state signal including a different number of states. A set status of a set-associative storage container in a computer system is determined. The set status identifies whether each set of the set-associative storage container is enabled or disabled. One of the state signals is selected that has a same number of states as a number of the sets that are enabled. The selected state signal is mapped to the sets that are enabled to assign each of the states of the selected state signal to a corresponding one of the sets that are enabled. A set selection of the set-associative storage container is output based on the mapping to randomly select one of the sets that are enabled from the set-associative storage container.

Abstract: Embodiments include a computer system for temporary pipeline marking for processor error workarounds, the computer system having a processor configured to perform a method. The method includes monitoring a pipeline of the processor for an event that is predetermined to place the processor in a stuck state that results in an errant instruction execution result due to the stuck state or repeated resource contention causing performance degradation. The pipeline is marked for a workaround action based on detecting the event. A clearing action is triggered based on the marking of the pipeline. The marking of the pipeline is cleared based on the triggering of the clearing action.