Abstract: A method and apparatus for performing division is described which first comprises approximating the short reciprocal of the divisor. A reciprocal bias adjustment factor is added to the approximation and the correctly biased short reciprocal is multiplied by a predetermined number of the most significant bits of the dividend and the product is truncated to generate a first quotient digit value. The multiplication takes place in a multiplier array having a rectangular aspect ratio with the long side having a number of bits at least as large as the number of bits required for the divisor. The short side of the multiplier array has a number of bits slightly greater by several guard bits than the number of bits required for a single quotient digit value, which is also determined to be the number of bits in the short reciprocal. The quotient digit value is multiplied by the full divisor and the exact product is subtracted from the dividend to yield an exact partial remainder.

Abstract: A method for approximating mathematical functions using polynomial expansions is implemented in a numeric processing system (10) which comprises a control and timing circuit (18), a microprogram store (20) and a multiplier circuit (34). The multiplier circuit (34) may comprise a rectangular aspect ratio multiplier circuit (40) having an additional ADDER INPUT to enable the repeated evaluation of first order polynomials to evaluate polynomial expansions associated with each mathematical function. A constant store (28) is used to store predetermined coefficients for the polynomial expansion associated with each mathematical functions. The microprogram store (20) is used to store argument transformation routines, polynomial expansions and result transformation routines associated with each mathematical function.

Abstract: An arithemtic circuit (10) which comprises an adder/rounder circuit (20) and a normalization estimation circuit (24) coupled in parallel to operand register (14, 19). A signed digit subtracter (25) subtracts the operands and inputs a signed digit difference to a pseudovalue converter (27). The pseudovalue converter (27) performs a three-bit overlapping scan of the signed digit differene to determine a bit location which corresponds to the approximate bit position of the most significant non-zero bit in the result of the arithmetic process performed in adder/rounder circuit (20). The pseudovalue converter (27) generates a pseudovalue in non-redundant format which contains its most significant non-zero bit in the selected bit position. The pseudovalue is output to a leading zero counter (28) which counts the number of leading zeroes in the pseudovalue. The number of leading zeroes is output to a barrel shifter (16) via an L-bus (30).

Abstract: A bidirectional variable bit shifter (10) is disclosed which comprises a latch/input driver (12) coupled to a word shift array (14) coupled to a nibble shift array (16) coupled to a bit shift array (18) coupled to a latch/output driver (20). The bidirectional variable bit shifter (10) further comprises three sense amps (24, 26, 28) coupled to the word, nibble and bit shift arrays (14, 16, 18) respectively, and the outputs of the three sense amps (24, 26, 28) are coupled to the input of a logic-OR gate (30) which has as its output an Indicator Bit signal. The word, nibble and bit shift arrays (14, 16, 18) are coupled to control decode circuit (22) which receives and decodes information from a Microcode Control Bus and from three shift count control buses.