In an aspect, a processor includes circuitry for iterative refinement approaches, e.g., Newton-Raphson, to evaluating functions, such as square root, reciprocal, and for division. The circuitry includes circuitry for producing an initial approximation; which can include a LookUp Table (LUT). LUT may produce an output that (with implementation-dependent processing) forms an initial approximation of a value, with a number of bits of precision. A limited-precision multiplier multiplies that initial approximation with another value; an output of the limited precision multiplier goes to a full precision multiplier circuit that performs remaining multiplications required for iteration(s) in the particular refinement process being implemented. For example, in division, the output being calculated is for a reciprocal of the divisor. The full-precision multiplier circuit requires a first number of clock cycles to complete, and both the small multiplier and the initial approximation circuitry complete within the first number of clock cycles.

In an aspect, a processor includes circuitry for iterative refinement approaches, e.g., Newton-Raphson, to evaluating functions, such as square root, reciprocal, and for division. The circuitry includes circuitry for producing an initial approximation; which can include a LookUp Table (LUT). LUT may produce an output that (with implementation-dependent processing) forms an initial approximation of a value, with a number of bits of precision. A limited-precision multiplier multiplies that initial approximation with another value; an output of the limited precision multiplier goes to a full precision multiplier circuit that performs remaining multiplications required for iteration(s) in the particular refinement process being implemented. For example, in division, the output being calculated is for a reciprocal of the divisor. The full-precision multiplier circuit requires a first number of clock cycles to complete, and both the small multiplier and the initial approximation circuitry complete within the first number of clock cycles.

A method includes receiving, by an x-bit adder, first and second addends. The x bits comprise a first portion and a second portion, the first portion is a power of two number of bits, and x is not a power of two. The method also includes computing a first sum of the first and second addends corresponding to the first portion. Computing the first sum provides a carry out bit. The method includes computing a non-incremented sum of the first and second addends corresponding to the second portion; computing an incremented sum of the first and second addends corresponding to the second portion; selecting one of the non-incremented sum and the incremented sum, responsive to the carry out bit, as a second sum; and providing a final sum by concatenating the second sum and the first sum.

A method includes receiving, by an x-bit adder, first and second addends. The x bits comprise a first portion and a second portion, the first portion is a power of two number of bits, and x is not a power of two. The method also includes computing a first sum of the first and second addends corresponding to the first portion. Computing the first sum provides a carry out bit. The method includes computing a non-incremented sum of the first and second addends corresponding to the second portion; computing an incremented sum of the first and second addends corresponding to the second portion; selecting one of the non-incremented sum and the incremented sum, responsive to the carry out bit, as a second sum; and providing a final sum by concatenating the second sum and the first sum.

A processing unit and a method for multiplying at least two multiplicands. The multiplicands are present in an exponential notation, that is, each multiplicand is assigned an exponent and a base. The processing unit is configured to carry out a multiplication of the multiplicands and includes at least one bitshift unit, the bitshift unit shifting a binary number a specified number of places, in particular, to the left; an arithmetic unit, which carries out an addition of two input variables and a subtraction of two input variables; and a storage device. A computer program, which is configured to execute the method, and a machine-readable storage element, in which the computer program is stored, are also described.

A processing unit and a method for multiplying at least two multiplicands. The multiplicands are present in an exponential notation, that is, each multiplicand is assigned an exponent and a base. The processing unit is configured to carry out a multiplication of the multiplicands and includes at least one bitshift unit, the bitshift unit shifting a binary number a specified number of places, in particular, to the left; an arithmetic unit, which carries out an addition of two input variables and a subtraction of two input variables; and a storage device. A computer program, which is configured to execute the method, and a machine-readable storage element, in which the computer program is stored, are also described.

A method comprising storing a plurality of entries, each entry of the plurality of entries associated with a portion of a range of input values, each entry of the plurality of entries comprising a set of coefficients defining a power series approximation; selecting first entry of the plurality of entries based on a determination that a floating point input value is within a portion of the range of input values that is associated with the first entry; and calculating an output value by evaluating the power series approximation defined by the set of coefficients of the first entry at the floating point input value.

A method comprising storing a plurality of entries, each entry of the plurality of entries associated with a portion of a range of input values, each entry of the plurality of entries comprising a set of coefficients defining a power series approximation; selecting first entry of the plurality of entries based on a determination that a floating point input value is within a portion of the range of input values that is associated with the first entry; and calculating an output value by evaluating the power series approximation defined by the set of coefficients of the first entry at the floating point input value.

A calculation processor for determining a digital output value from a digital input value based on an exponent value a, the processor comprising a first calculation block, a second calculation block and a final calculation block. The first calculation block initializes an intermediate value and an error value depending on a position of a Most Significant Bit of a significant part of the input value. The second calculation block is configured to perform repeatedly, until an exit criterion is fulfilled, the incrementation of a counter value, the determination of a power error value based on the error value and, if the power error value is larger than or equal to an error threshold, adjustment of the intermediate value y by multiplying the intermediate value with an adaptation value and setting the error value to the power error value divided by the base value. If the power error value is smaller than the error threshold, the error value is set to the power error value. The final calculation block is configured to set the output value to the intermediate value.

A calculation processor for determining a digital output value from a digital input value based on an exponent value a, the processor comprising a first calculation block, a second calculation block and a final calculation block. The first calculation block initializes an intermediate value and an error value depending on a position of a Most Significant Bit of a significant part of the input value. The second calculation block is configured to perform repeatedly, until an exit criterion is fulfilled, the incrementation of a counter value, the determination of a power error value based on the error value and, if the power error value is larger than or equal to an error threshold, adjustment of the intermediate value y by multiplying the intermediate value with an adaptation value and setting the error value to the power error value divided by the base value. If the power error value is smaller than the error threshold, the error value is set to the power error value. The final calculation block is configured to set the output value to the intermediate value.