A semiconductor chip is described having a functional unit that can execute a first instruction and execute a second instruction. The first instruction is an instruction that multiplies two operands. The second instruction is an instruction that approximates a function according to C0+C1X2+C2X2.sup.2. The functional unit has a multiplier circuit. The multiplier circuit has: i) a first input to receive bits of a first operand of the first instruction and receive bits of a C1 term of the second instruction; ii) a second input to receive bits of a second operand of the first instruction and receive bits of a X2 term of the second instruction.

Mathematical functions are computed in a single pipeline performing a polynomial approximation (e.g. a quadratic approximation, or the like); and one or more data tables corresponding to at least one of the RCP, SQRT, EXP or LOG functions operable to be coupled to the single pipeline according to one or more opcodes; wherein the single pipeline is operable for computing at least one of RCP, SQRT, EXP or LOG functions according to the one or more opcodes. SIN and COS are also computed using the pipeline according to the approximation ((1)^IntX)*Sin(*Min(FracX, 1.0FracX)/Min(FracX, 1.0FracX). A pipeline portion approximates Sin(*FracX) using tables and interpolation and a subsequent stage multiplies this approximation by FracX. For input arguments of x close 1.0. LOG 2(x1)/(x1) is computed using a first pipeline portion using tables and interpolation and subsequently multiplied by (x1). A DIV operation may also be performed with input arguments scaled up to avoid underflow as needed.

Systems and methods for a split phase accumulator having a plurality of sub phase accumulators are provided. Each sub phase accumulator receives a portion of a frequency control word. The first sub phase accumulator includes a first register and the remaining sub phase accumulators include a register and an overflow register. At each discrete point in time, the first sub phase accumulator is configured to be responsive to the first portion of the frequency control word at that discrete point in time and to the first sub phase accumulator value at the immediately previous discrete point in time, and each of the remaining sub phase accumulators is configured to be responsive to a value of its corresponding portion of the frequency control word at that discrete point in time and to the same second sub phase accumulator value at the immediately previous discrete point in time.

Systems and methods for a split phase accumulator having a plurality of sub phase accumulators are provided. Each sub phase accumulator receives a portion of a frequency control word. The first sub phase accumulator includes a first register and the remaining sub phase accumulators include a register and an overflow register. At each discrete point in time, the first sub phase accumulator is configured to be responsive to the first portion of the frequency control word at that discrete point in time and to the first sub phase accumulator value at the immediately previous discrete point in time, and each of the remaining sub phase accumulators is configured to be responsive to a value of its corresponding portion of the frequency control word at that discrete point in time and to the same second sub phase accumulator value at the immediately previous discrete point in time.

An aspect includes an apparatus for evaluating a mathematical function at an input value. The apparatus includes a selector for selecting a mathematical function, an input for a value at which to evaluate the function, an identifier for identifying an interval containing the input value. The interval is described by at least one polynomial function. At least one control point representing the polynomial function is retrieved from at least one look up table, and the polynomial function can be derived from the control points. The function is evaluated at the input value and an output of the evaluation is used as a value of the function at that input value.