Abstract: A method for hiding implicit bit corrections in a partial product adder array in a binary and hexadecimal floating-point multiplier such that no additional adder stages are needed for the implicit bit corrections. Two leading-one correction terms are generated for the fraction in the multiplier floating-point number and two leading-one correction terms are generated for the fraction in the multiplicand floating-point number. The floating-point numbers may be single-precision or double-precision. Each leading-one correction term for the single-precision case is appended to the left of an intermediate partial product sum in the adder array that is an input to an adder so as to not to extend the bits in the input further to the left than the bits in another input to the adder. Each leading-one correction term for the double-precision case replaces an adder input that is unused when base-2 floating-point numbers are multiplied.

Abstract: A method for hiding implicit bit corrections in a partial product adder array in a binary and hexadecimal floating-point multiplier such that no additional adder stages are needed for the implicit bit corrections. Two leading-one correction terms are generated for the fraction in the multiplier floating-point number and two leading-one correction terms are generated for the fraction in the multiplicand floating-point number. The floating-point numbers may be single-precision or double-precision. Each leading-one correction term for the single-precision case is appended to the left of an intermediate partial product sum in the adder array that is an input to an adder so as to not to extend the bits in the input further to the left than the bits in another input to the adder. Each leading-one correction term for the double-precision case replaces an adder input that is unused when base-2 floating-point numbers are multiplied.

Abstract: A method for operating a fused-multiply-add pipeline in a floating-point unit of a processor is disclosed. A multiplication is initially performed between a first operand and a second operand in a multiplier block to obtain a set of partial product results. The partial product results are sent to a carry-save adder block. A partial product reduction is performed on the partial product results to generate a carry-save result having a sum term and a carry term. The carry-save result is then formatted to generate a carry-out bit. The carry-save result is added to a third operand to generate a final result.

Abstract: A method for hiding implicit bit corrections in a partial product adder array in a binary and hexadecimal floating-point multiplier such that no additional adder stages are needed for the implicit bit corrections. Two leading-one correction terms are generated for the fraction in the multiplier floating-point number and two leading-one correction terms are generated for the fraction in the multiplicand floating-point number. The floating-point numbers may be single-precision or double-precision. Each leading-one correction term for the single-precision case is appended to the left of an intermediate partial product sum in the adder array that is an input to an adder so as to not to extend the bits in the input further to the left than the bits in another input to the adder. Each leading-one correction term for the double-precision case replaces an adder input that is unused when base-2 floating-point numbers are multiplied.

Abstract: A method for hiding implicit bit corrections in a partial product adder array in a binary and hexadecimal floating-point multiplier such that no additional adder stages are needed for the implicit bit corrections. Two leading-one correction terms are generated for the fraction in the multiplier floating-point number and two leading-one correction terms are generated for the fraction in the multiplicand floating-point number. The floating-point numbers may be single-precision or double-precision. Each leading-one correction term for the single-precision case is appended to the left of an intermediate partial product sum in the adder array that is an input to an adder so as to not to extend the bits in the input further to the left than the bits in another input to the adder. Each leading-one correction term for the double-precision case replaces an adder input that is unused when base-2 floating-point numbers are multiplied.

Abstract: A method for operating a fused-multiply-add pipeline in a floating-point unit of a processor is disclosed. A multiplication is initially performed between a first operand and a second operand in a multiplier block to obtain a set of partial product results. The partial product results are sent to a carry-save adder block. A partial product reduction is performed on the partial product results to generate a carry-save result having a sum term and a carry term. The carry-save result is then formatted to generate a carry-out bit. The carry-save result is added to a third operand to generate a final result.

Abstract: A system for handling denormal floating point operands when the result must be normalized. A leading zero counter (lzc) on the operand B (opB) is used to limit alignment shifts when opB is denormal but is much greater than the product of operands A and C, i.e. AC. By limiting the additional shift of B during normalization, by the number of leading zeros in opB, no increase is needed in the output bus of the alignment shifter. Furthermore, the additional shift may be done either in the alignment shifter, or postponed to a later stage in the pipeline, where the result is normalized.

Abstract: A floating point processor unit includes a shift amount calculation circuit within a normalizer portion of the floating point unit, wherein the shift amount calculation circuit is utilized to compute the normalizer shift amount for a log estimate instruction that runs as a pipelinable instruction.

Abstract: A system for performing floating point arithmetic operations including an input register adapted for receiving an operand. The system also includes a mechanism for performing a shift or masking operation in response to determining that the operand is in an un-normalized format. The system also includes instructions for performing single precision incrementing of the operand in response to determining that the operand is single precision, that the operand requires the incrementing based on the results of a previous operation and that the previous operation did not perform the incrementing. The operand was created in the previous operation. The system further includes instructions for performing double precision incrementing of the operand in response to determining that the operand is double precision, that the operand requires the incrementing based on the results of the previous operation and that the previous operation did not perform the incrementing.

Abstract: A method and system for performing a binary mode and hexadecimal mode Multiply-Add floating point operation in a floating point arithmetic unit according to a formula A*C+B, wherein A, B and C operands each have a fraction and an exponent part expA, expB and expC and the exponent of the product A*C is calculated and compared to the exponent of the addend under inclusion of an exponent bias value dedicated to use unsigned biased exponents, wherein the comparison yields a shift amount used for aligning the addend with the product operand, wherein a shift amount calculation provides a common value CV for both binary and hexadecimal according to the formula (expA+expC?expB+CV).

Abstract: A floating point processor unit includes a shift amount calculation circuit within a normalizer portion of the floating point unit, wherein the shift amount calculation circuit is utilized to compute the normalizer shift amount for a log estimate instruction that runs as a pipelinable instruction.

Abstract: A system for handling denormal floating point operands when the result must be normalized. A leading zero counter (lzc) on the operand B (opB) is used to limit alignment shifts when opB is denormal but is much greater than the product of operands A and C, i.e. AC. By limiting the additional shift of B during normalization, by the number of leading zeros in opB, no increase is needed in the output bus of the alignment shifter. Furthermore, the additional shift may be done either in the alignment shifter, or postponed to a later stage in the pipeline, where the result is normalized.

Abstract: The invention proposes a Floating Point Unit (1) with fused multiply add, with one addend operand (eb, fb) and two multiplicand operands (ea, fa; ec, fc), with a shift amount logic (2) which based on the exponents of the operands (ea, eb and ec) computes an alignment shift amount, with an alignment logic (3) which uses the alignment shift amount to align the fraction (fb) of the addend operand, with a multiply logic (4) which multiplies the fractions of the multiplicand operands (fa, fc), with a adder logic (5) which adds the outputs of the alignment logic (3) and the multiply logic (4), with a normalization logic (6) which normalizes the output of the adder logic (5), which is characterized in that a leading zero logic (7) is provided which computes the number of leading zeros of the fraction of the addend operand (fb), and that a compare logic (8) is provided which based on the number of leading zeros and the alignment shift amount computes select signals that indicate whether the most significant bits of t

Abstract: A method for handling denormal floating point operands when the result must be normalized. A leading zero counter (lzc) on the operand B (opB) is used to limit alignment shifts when opB is denormal but is much greater than the product of operands A and C, i.e. AC. By limiting the additional shift of B during normalization, by the number of leading zeros in opB, no increase is needed in the output bus of the alignment shifter. Furthermore, the additional shift may be done either in the alignment shifter, or postponed to a later stage in the pipeline, where the result is normalized.

Abstract: A system for performing floating point arithmetic operations including a plurality of stages making up a pipeline, the stages including a first stage and a last stage. The system also includes a register file adapted for receiving a store instruction for input to the pipeline, where the data associated with the store instruction is dependent on a previous operation still in the pipeline. The system further includes a store register adapted for outputting the data associated with the store instruction to memory and a control unit having instructions. The instructions are directed to inputting the store instruction into the pipeline and to providing a path for forwarding the data associated with the store instruction from the last stage in the pipeline to the store register for use by the store instruction if the previous operation immediately precedes the store operation in the pipeline and if there is a data type match between the store instruction and the previous operation.

Abstract: A system for performing limited out-of order execution of floating point loads. The system includes a plurality of stages making up a pipeline, the stages including an early stage. The system also includes a mechanism for inputting an arithmetic instruction into the pipeline, the arithmetic instruction including a result address. The mechanism also determines if the arithmetic instruction causes a write after write (WAW) condition to occur before writing a result of the arithmetic instruction to the result address. The determining includes comparing the result address to a load address associated with a load instruction subsequent to the arithmetic instruction in the pipeline. The load data associated with the load instruction was written to the load address in the early stage of the pipeline. A WAW condition occurs if the result address is equal to the load address. Writing a result of the arithmetic instruction is suppressed in response to the WAW condition occurring.

Abstract: A system for performing floating point arithmetic operations including an input register adapted for receiving an operand. The system also includes computer instructions for performing single precision incrementing of the operand in response to determining that the operand is single precision, that the operand requires the incrementing based on the results of a previous operation and that the previous operation did not perform the incrementing. The operand was created in the previous operation. The system further includes instructions for performing double precision incrementing of the operand in response to determining that the operand is double precision, that the operand requires the incrementing based on the results of the previous operation and that the previous operation did not perform the incrementing.

Abstract: A system for performing floating point arithmetic operations including a plurality of stages making up a pipeline, the stages including a first stage and a last stage. The system also includes a register file adapted for receiving a store instruction for input to the pipeline, where the data associated with the store instruction is dependent on a previous operation still in the pipeline. The system further includes a store register adapted for outputting the data associated with the store instruction to memory and a control unit having instructions. The instructions are directed to inputting the store instruction into the pipeline and to providing a path for forwarding the data associated with the store instruction from the last stage in the pipeline to the store register for use by the store instruction if the previous operation immediately precedes the store operation in the pipeline and if there is a data type match between the store instruction and the previous operation.

Abstract: A system for performing floating point arithmetic operations including an input register adapted for receiving an operand. The system also includes a mechanism for performing a shift or masking operation in response to determining that the operand is in an un-normalized format. The system also includes instructions for performing single precision incrementing of the operand in response to determining that the operand is single precision, that the operand requires the incrementing based on the results of a previous operation and that the previous operation did not perform the incrementing. The operand was created in the previous operation. The system further includes instructions for performing double precision incrementing of the operand in response to determining that the operand is double precision, that the operand requires the incrementing based on the results of the previous operation and that the previous operation did not perform the incrementing.

Abstract: The present invention provides for reducing power across the entirety of a processor in a series of incremental steps. The clocking power requirements of a processor are evaluated through a power analysis and pre-programmed into a power train generator. A state machine control ramp logic comprising pre-programmed states resets a delay counter and issues state instructions to a pulse train generator. A pulse train generator outputs constant pulse trains and variable pulse trains that mask the original clocking power frequency. The pulse trains are distributed through a timed clock control distribution network to local clock buffers. The conditioned pulse trains step up or step down the clocking power, to the entirety of the processor, resulting in a smoothing of the clocking power switching. The smoothing of the clocking power reduces electrical spikes, surges and capacitance within the processor.