Abstract: A method for forming a sum of the absolute value of the difference between each pair of numbers of respective first and second sets of numbers. The method includes forming the difference between a first number of the first set and a second number of the second set. Next this difference is either added to or subtracted from a running sum based upon the sign of this difference. This is repeated until all number pairs are either added to or subtracted from the running sum of absolute values of the differences. The initial subtraction is used to set a status bit in a flag register (211) based upon a less than zero output or the carry-out. The status bit controls whether the difference is added to or subtracted from the running sum. The conditional addition to or subtraction from the running sum may generate a carry-out representing the most significant bit of the running sum. This carry-out is stored and later added to the running sum to recover the most significant overflow bits.

Abstract: The present invention is a magnitude comparator that receives as inputs two 32-bit 1-of-4 operands. The magnitude comparator generates a carry indicator if the value of the first operand is less than or equal to the value of the second operand. The magnitude comparator generates a no carry indicator if the value of the first operand is greater than the value of the second operand.

Abstract: In one embodiment, an adder is sectioned into a plurality of operational blocks; namely, a first block, second block, and third block. The first block in a first section generates sum bits and a section carry signal. The second block in the second section generates a second plurality of sum bits and a first block carry signal. A third block in the second section receives both the section carry signal and the first block carry signal. The third block includes a carry processor which receives the section carry signal and outputs a second block carry signal corresponding to the third block.

Abstract: A circuit and method for deriving an adder output bit from adder input bits, a multiplier circuit, a method of multiplying, a microprocessor and digital signal processor (DSP) employing the circuit or the method and a method of selecting weights and thresholds for logic gates. In one embodiment, the circuit includes: (1) first, second and third logic gates that generate intermediate bits based on threshold comparisons of concatenations of ones of the adder input bits and (2) combinatorial logic that generates the adder output bit from the intermediate bits. In one embodiment, the multiplier includes a summer having at least two inputs with corresponding weights, the inputs corresponding to bits of a multiplicand, the weights based on a multiplier, the summer generating a weighted sum of the multiplicand that represents a multiplication of the multiplicand and the multiplier that is a function of the weighted sum.

Abstract: A programmable function block comprises a core logic circuit having a first argument input group consisting of first through fourth argument input terminals, a second argument input group consisting of first through fourth argument input terminals, first through third configuration input terminals, a core logic carry output terminal, a core logic carry generation output terminal, a core logic carry propagation output terminal, a ripple-core logic carry input terminal, and a sum output terminal. Connected to interconnection wires and the first and the second argument input groups, an input block includes eighth input selection units for selecting, as eight input selected signals, eight ones of signals on the interconnection wires, a fixed logic value of “1”, and a fixed logic value of “0”. Connected to the first through the third configuration input terminals, respectively, first through third memory circuits stores, as first through third stored logic values, a logic value of one bit.

Abstract: A high-speed carry-lookahead binary adder is disclosed. The binary adder includes multiple rows of carry-lookahead circuits, a half-sum module, and a sum/carry module. A first carry-lookahead circuit row includes multiple eight-bit group generate circuits and multiple eight-bit group propagate circuits. Each of the eight-bit group generate circuits produces a generate signal for a corresponding bit location. Each of the eight-bit group propagate circuits produces a propagate signal for a corresponding bit location. The half-sum module is utilized to generate a half-sum signal. By utilizing the half-sum signal, the generate signals, and the propagate signals, the sum/carry module generates sum signals and a carry signal.

Abstract: A parallel adder is disclosed. The parallel adder includes a number of computational cells that operate to generate odd sum bits based on generate and propagate terms recursively computed and a plurality of carry-in bits. The parallel adder further includes a number of selection cells that are independent of the computational cells and operate to select and output even sum bits from a number of candidate sum bits, the selection being made in accordance with predetermined ones of said recursively computed generate and propagate terms.

Abstract: A circuit is disclosed herein which generates the sum of two numbers (A and B) and the sum plus 1 in parallel so as not to take any additional time to generate the sum plus 1 value. The circuit comprises a carry look-ahead (CLA) tree portion and a summer portion. The CLA tree portion generates carry bits, as well as the logical relationship A.sub.i XOR B.sub.i, for application to a summer for bit position i. The carry bits contain information for either inverting or not inverting the A.sub.i XOR B.sub.i bit for both the sum and the sum plus 1 output of the summer. The sum bit and sum plus 1 bit are generated at approximately the same time.

Abstract: An adder (300) generates encoded outputs to conserve power. In particular, the adder provides "B2" encoded outputs which only drive one bit per every two bits at a time on conductive lines in a data processing system. A binary input is encoded by an encoder (800, 304) to generate a plurality of bits. The plurality of bits are concatenated to form a plurality of sum values. A portion of the plurality of sum values are then selectively output in response to a logic value of a carry kill signal, a carry generate signal, and a carry propagate signal.

Abstract: Disclosed is an integrated pass-transistor logic circuit which includes a conditional sum adder. This sum adder has seven sum generation blocks of module form and two carry generation blocks. With the sum adder, before carry propagation which is generated through multiplexer chain in respective sum generation blocks arrives at the final stage of the multiplexer chain, the final stage is driven by block carry signals BC.sub.i and /BC.sub.i provided from the respective carry generation blocks. The carry generation and the sum generation occur individually in the conditional sum adder. The sum generation blocks are constituted with pass-transistor logic and the carry generation blocks with Complementary Metal Oxide Semiconductor (CMOS) logic, the sum adder has a more faster operation speed and a more lower power dissipation, as compared with the prior art conditional sum adder having either the pass-transistor logic or the CMOS logic.

Abstract: A microprocessor (10) and system implementing the same is disclosed, in which stack-based register address calculation is performed in a single add cycle for instructions involving a PUSH operation. The microprocessor (10) includes a floating-point unit (FPU) (31) having a register stack (52.sub.ST) and a stack pointer (FSP), for executing floating-point instructions containing relative register addresses (REG) based upon the contents (TOP) of the stack pointer (FSP). The instructions may involve PUSH operations, in which an operand is added to the stack of operands in the register stack (52.sub.ST). Register addressing circuitry (125, 125') includes an adder (122; 122') for generating the sum of the contents (TOP) of the stack pointer (FSP) and the relative register address (REG) of the instruction, and an adder/decrementer (120) for generating the sum of the contents (TOP) of the stack pointer (FSP) and the relative register address (REG) of the instruction minus one, to account for the PUSH.

Abstract: An integrated circuit including an adder that is a series of one-bit cascaded adder cells. The circuits that implement the adder cells are not all alike. The adder cells are of two types: an even adder cell and an odd adder cell. The even adder cells receive all inputs as noninverted inputs, provide as outputs a noninverted sum bit output and the inverse of the carry-out bit. The odd adder cells receive as inputs the inverse of the carry-in bit, all other inputs are noninverted, and provides as outputs a noninverted sum bit and a noninverted carry-out bit.

Abstract: A high-speed carry-lookahead binary adder is disclosed. The binary adder includes multiple rows of carry-lookahead circuits, a half-sum module, and a sum/carry module. A first carry-lookahead circuit row includes multiple four-bit group generate circuits and multiple four-bit group propagate circuits. Each of the four-bit group generate circuits produces a generate signal for a corresponding bit location. Each of the four-bit group propagate circuits produces a propagate signal for a corresponding bit location. The half-sum module is utilized to generate a half-sum signal. By utilizing the half-sum signal, the generate signals, and the propagate signals, the sum/carry module generates sum signals and a carry signal.

Abstract: A high-performance carry lookahead adder (CLA) which can reduce the delay time of the whole adder by constructing a carry generator used therein with NMOS logics, thereby effecting a high-speed operation of the adder along with a lower power-consumption. The carry generator receives an exclusive-OR value P(i, i=1,2,3,4) and a logic product value G(i) of two data, and an initial carry value C(1), and performs a function of G(4)+P(4).multidot.G(3)+P(4).multidot.P(3).multidot.G(2)+P(4).multidot.P(3 ).multidot.P(2).multidot.G(1)+P(4).multidot.P(3).multidot.P(2).multidot.P(1 ).multidot.C(1) to output a final carry value C(5). The carry generator includes a first NMOS transistor for executing an operation of P(4).multidot.G(3), second and third NMOS transistors for executing an operation of P(4).multidot.P(3).multidot.G(2), fourth to sixth NMOS transistors for executing an operation of P(4).multidot.P(3).multidot.P(2).multidot.G(1), seventh to eleventh NMOS transistors for executing an operation of P(4).multidot.