Abstract: A technique for checking an exponent calculation for an execution unit that supports floating point operations includes generating, using a residue prediction circuit, a predicted exponent residue for a result exponent of a floating point operation. The technique also includes generating, using an exponent calculation circuit, the result exponent for the floating point operation and generating, using the residue prediction circuit, a result exponent residue for the result exponent. Finally, the technique includes comparing the predicted exponent residue to the result exponent residue to determine whether the result exponent generated by the exponent calculation circuit is correct and, if not, signaling an error.

Abstract: An approach is provided in which a processor includes an adder that concurrently generates one or more intermediate results and a boundary indicator based upon instructions retrieved from a memory area. The boundary indicator indicates whether a collective result generated from the intermediate results is within a boundary precision value.

Abstract: A method and system for tracing in a data processing system. The method includes receiving a plurality of signals associated with an operation during execution of the operation. The method also includes, in response to an indication that the operation is a multiphase operation, during execution of the operation, selection logic, during a first phase of the multiphase operation, selecting and outputting as a trace signal a first signal of the plurality of signals, and during a second phase of the multiphase operation, selecting and outputting as the trace signal a second signal of the plurality of signals.

Abstract: A method and system for tracing in a data processing system. The method includes receiving a plurality of signals associated with an operation during execution of the operation. The method also includes, in response to an indication that the operation is a multiphase operation, during execution of the operation, selection logic, during a first phase of the multiphase operation, selecting and outputting as a trace signal a first signal of the plurality of signals, and during a second phase of the multiphase operation, selecting and outputting as the trace signal a second signal of the plurality of signals.

Abstract: A technique for checking an exponent calculation for an execution unit that supports floating point operations includes generating, using a residue prediction circuit, a predicted exponent residue for a result exponent of a floating point operation. The technique also includes generating, using an exponent calculation circuit, the result exponent for the floating point operation and generating, using the residue prediction circuit, a result exponent residue for the result exponent. Finally, the technique includes comparing the predicted exponent residue to the result exponent residue to determine whether the result exponent generated by the exponent calculation circuit is correct and, if not, signaling an error.

Abstract: According to one aspect of the present disclosure, a method and technique for encoding densely packed decimals is disclosed. The method includes: executing a floating point instruction configured to perform a floating point operation on decimal data in a binary coded decimal (BCD) format; determining whether a result of the operation includes a rounded mantissa overflow; and responsive to determining that the result of the operation includes a rounded mantissa overflow, compressing a result of the operation from the BCD-formatted decimal data to decimal data in a densely packed decimal (DPD) format by shifting select bit values of the BCD formatted decimal data by one digit to select bit positions in the DPD format.

Abstract: A residue generator for calculation and correction of a residue value. The residue generator includes a residue-generation tree connected with an operand register at an input of the residue generator including a plurality of register-bits receiving and carrying bits of numerical data.

Abstract: A residue generator for calculation and correction of a residue value. The residue generator includes a residue-generation tree connected with an operand register at an input of the residue generator including a plurality of register-bits receiving and carrying bits of numerical data.