Abstract: Arctangents (tan.sup.-1) are calculated utilizing binary floating point numbers through much of the function's range by extracting into an Integer Register (54) as an index ("i") the exponent and a specified number of fraction bits from a Floating Point Register(s) (60). The index is utilized by an Integer Unit (52) to index into tables of polynomial coefficients and reference values. The floating point difference between the absolute value of the argument(s) and the reference value selected by the index is a polynomial linear term. The coefficients in the table entry selected by the index are multiplied in a Floating Point Unit (58) by integral powers of the linear term. The Floating Point Unit (58) then sums the high order polynomial terms. The zero.sup.th level term added to the product of the first level term multiplied by the linear term forms a "big" term.

Abstract: Rounding error can be reduced when evaluating binary floating point polynomials utilizing a Floating Point Unit (58) by first computing the sum of products of second and higher order polynomial terms. Next, the Floating Point Unit (58) adds a zero.sup.th level term to the product of a first order coefficient and an independent variable to form a "Big" term. The Floating Point Unit (58) calculates as a "Little" term the rounding error resulting from the computation of the "Big" term. The "Little" term is then added to the sum of products of higher order terms to form an "Intermediate" term. Finally, the Floating Point Unit (58) adds the "Big" term to the "Intermediate" term to form the polynomial result corrected by the rounding error introduced by the computation of the low order terms.

Abstract: A compiler and/or a compilation method is used to change or compile a plurality of instructions in memory from a form which is better understood by a human user to a form which is readily executed by a microprocessor. In doing this compilation, execution optimization is usually performed. A more efficient job of optimization (and therefore improved software performance) is achieved by correctly finding/identifying induction variables in code loops which may be used in the compiler's optimization routines. Induction variable properties can be found by constructing and analyzing an integer transfer matrix wherein the values of variables at the beginning of one execution of the loop are related functionally to the values of variables at the end of the one execution of the loop. This matrix can be effectively processed using eigenvalue processing using integer unimodular matrices to determine induction variable properties which were previously missed by prior methods, thereby improving performance.

Abstract: A data processor and method are used to find log.sub.p (x) wherein p is a numerical base and x is a floating point value. The method begins by deriving a number y from the quantity x wherein the number y has a predetermined sign portion, a predetermined exponent portion, and the fraction portion f. The predetermined fraction portion f being a truncated portion of x. A logarithm to the predetermined base p of the number y is found by calculating:log.sub.p (y)=-log.sub.p (a)+log.sub.p (1+(ay-1))where the constant a is read from a memory table of constants indexed by an index i. Index i is calculated from y where the fraction portion f of y lies in the range of 1.ltoreq.y<2 and the position in this range determines index i. The log.sub.p (y), once determined, is used to find the log.sub.p (x) in an accurate manner as indicated in equation 16 herein.

Abstract: A data processor and method are used to find log.sub.p (x) wherein p is a numerical base and x is a floating point value. The method begins by deriving a number y from the quantity x wherein the number y has a predetermined sign portion, a predetermined exponent portion, and the fraction portion f, the predetermined fraction portion f being a truncated portion of x. A logarithm to the predetermined base p of the number y is found by calculating:log.sub.p (y)=-log.sub.p (a)+log.sub.p (1+(ay-1))where the constant a is read from a memory table of constants indexed by an index i. Index i is calculated from y where the fraction portion f of y lies in the range of 1.ltoreq.y<2 and the position in this range determines index i. The log.sub.p (y), once determined, is used to find the log.sub.p (x) in an accurate manner as indicated in equation 16 herein.

Abstract: A method and apparatus used for performing a floating pointing operation has the ability to calculate a square root of a number. An approximation to the inverse of the square root of the number is provided via a step (18). Steps (20 and 22) are used to improve the precision of the inverse of the square root until a predetermined precision is attained. The inverse of the square root, which has a predetermined precision, is used along with the number to generate both an exact floating point value and a small floating point value via steps (24 and 26). The exact and small floating point values are added together in a sum and manipulated to fit into the floating point representation available to the apparatus. The sum is a substantially close approximation to the square root of the number and is either output directly or slightly modified numerically to more accurately represent the square root of the number.

Abstract: An immunoassay procedure is provided which exhibits increased specificity over current procedures. The procedure allows the differentiation of animals infected with Brucella abortus from animals vaccinated with Brucella abortus Strain 19. The invention employs unique monospecific monoclonal antibodies having particular affinity, specificity and binding characteristics directed to a B. abortus lipopolysaccharide antigen. The invention also concerns continuous hybrid cell lines for producing the unique monoclonal antibodies.

Abstract: Thiol protease inhibitors are disclosed having the formula: ##STR1## or an optical isomer thereof, or a pharmaceutically acceptable salt thereof, wherein:n is 0 or 1;m is 0, 1 or 2;X is H or an N-protecting group;each Y is independently an optionally protected .alpha.-amino acid residue;R is an optionally protected .alpha.-amino acid side chain that is H or CH.sub.3 or that is bonded to the .alpha.-carbon atom to which it is attached by a methylene, methine or phenyl radial; andR' is optionally substituted aryl.

Abstract: A plurality of processing units, each having a local memory connected thereto is disclosed. A write sense controller is also connected to each of the processing units to transmit a memory write word into a shared portion of local memory over a reflective memory line. Other write sense controllers receive the memory words from the reflective memory bus and cause them to be written into corresponding storage locations in the shared partitions of their local memories.

Abstract: Thiol protease inhibitors are disclosed having the formula: ##STR1## or an optical isomer thereof, or a pharmaceutically acceptable salt thereof, wherein:n is 0 or 1;m is 0, 1 or 2;X is H or an N-protecting group;each Y is independently an optionally protected .alpha.-amino acid residue;R is an optionally protected .alpha.-amino acid side chain that is H or CH.sub.3 or that is bonded to the .alpha.-carbon atom to which it is attached by a methylene, methine or phenyl radical; andR' is optionally substituted aryl.

Abstract: An antibacklash beveled gear drive is disclosed. The drive is constructed adjust for intial misalignment and subsequent wear. One of the gears is journaled on a driven shaft and has a biasing means which bump the gears into engagement.

Abstract: A pipe handling machine having vertical tracks mounted on a rotatable base. A carriage is mounted on the vertical tracks for vertical movement. A multisection telescoping boom is mounted on the carriage, and a pipe-engaging head is mounted on the end of the boom. The base may be carried on a movable trolley, which engages a set of tracks. The tracks run across the rig floor, from well center to a setback area. A second set of tracks may run across the rig floor, transverse to the first set.

Abstract: An interference warning device for an oil well drilling rig having a derrick, traveling equipment, a racker arm, and a block retractor. Fluid activated sensors provide electric signals when the traveling equipment is within a selected vertical distance from the racker arm, when the racker arm is within a selected horizontal distance from the vertical axis of the derrick, or when the block retractor has extended the traveling equipment to within a selected distance from the fully extended position. The operator is informed when any one of the sensors is activated, cautioned when any two of the sensors are activated, and warned when all three sensors are activated. The drawworks may be braked when all three sensors are activated.

Abstract: A well tool and method for making up and breaking out connections between sections of drill pipe. The tool will jump the upper pipe section out of the connection when the connection has been completely unthreaded, and will guide the upper pipe section during stabbing. A piston and cylinder assembly is mounted on the carriage for raising and lowering the pipe spinner relative to the carriage. The tool also has an actuator and a pilot valve for automatically opening the clamping cylinders of the spinner whenever the upper pipe section is raised by the pipe elevator.

Abstract: A top drive well drilling apparatus, having a drive unit for rotating a drill string. The drive unit is connected to a carriage, which guides the drive unit along a vertical guide track. A wrench assembly, for making and breaking connections between the stem of the drive unit and the drill string, can be moved between a working position along the stem and a retracted position away from the stem. The wrench assembly can also be moved vertically, and is mounted on the carriage.

Abstract: Composite fluorocarbon cation exchange membrane having at least two layers of fluorinated polymer containing pendant side chains with sulfonyl groups wherein the equivalent weight of one such layer differs from the adjacent layer by at least 100.

Abstract: Solutions are disclosed with solvents having completely halogenated, saturated, hydrocarbon backbones and solubility parameters within a particular range. Preferred solvent have at least one ether linkage. An exemplary solvent is ##STR1## wherein X is F, Cl, Br, and I; n is 0, 1, and 2; m is 1, 2, and 3; and Y is COOCH.sub.3 and SO.sub.2 F. The solutions include perfluorinated copolymers having high equivalent weight which have been prepared from tetrafluoroethylene and perfluorinated sulfonyl fluoride- or carboxyl-containing vinyl monomers.

Abstract: Multilayer fluorinated cation exchange membranes prepared by coextrusion of precursor polymers.