RTC Fixed-Point Coding for Carry-Free Parallel ALU Circuits

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Solution Overview

Problem

Modern parallel processing chips face challenges in supporting carry-calculation due to dependencies on carry bit computing, leading to complexity in arithmetic-logic unit (ALU) circuitry design and limiting the parallelization degree and computation units in GPUs, CPUs, TPUs, NPUs, and other computing devices.

Innovation Solution

Implementing a redundancy-tolerated symmetric binary coding (RTC) method for fixed-point number coding in ALU circuitry, ensuring each integer has a unique representation and allowing constant-time verification, simplifying carry bit computation, and enabling simpler CMOS circuit designs for faster parallel computing operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional binary coding is used for carry-calculation, then arithmetic operations can be performed, but the ALU circuitry design becomes complex and parallelization degree is limited

Engineering Contradiction:
Improveparallelization degreeVSAvoidALU circuitry complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the addition operation into independent bit-position operations using redundant number system representation. Each bit position can be processed independently without carry propagation to adjacent positions, enabling parallel processing of multiple bit positions simultaneously. This segmentation eliminates the sequential dependency inherent in traditional binary addition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter representation from standard binary to a redundant number system where each digit can take multiple values (e.g., -1, 0, 1). This parameter change allows the sum of two digits at any position to remain within a manageable range, eliminating the need for carry calculation and simplifying the ALU circuitry while enabling higher parallelization.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If carry bit computing is implemented, then accurate addition can be achieved, but the computation time increases and constant-time operation is not achieved

Engineering Contradiction:
Improveaddition accuracyVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The addition operation is segmented into independent bit-position operations where each position can be processed simultaneously. The redundant number system representation ensures that the sum at each position can be determined independently without waiting for carry bits from previous positions, achieving constant-time addition regardless of the number of bits.

Inventive Principle:
Principle #1Segmentation

3Productivity

If more computation units are added to increase parallel processing capability, then productivity improves, but device complexity and area increase

Engineering Contradiction:
Improvecomputation units quantityVSAvoidchip area
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent enables segmentation of computation into independent bit-position operations that can be processed in parallel. This allows the same ALU unit to handle multiple bit positions simultaneously through parallel processing, effectively increasing computation units without physically adding more hardware components, thus improving productivity without proportionally increasing chip area.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS12511123B2Fast carry-calculation oriented redundancy-tolerated fixed-point number coding for massive parallel ALU circuitry design in GPU, TPU, NPU, AI infer chip, CPU, and other computing devices
Publication Date: 2025.12.30 ZHOU JUN
  • US12511123B2 patent drawing
  • US12511123B2 patent drawing
  • US12511123B2 patent drawing

AI summary

A code method, a computer program product, and a system, for implementing a code method of Redundancy-Tolerated symmetric binary Coding (RTC) for massive parallel ALU circuitry design in GPU (Graphics Processing Unit), TPU (Tensor Processing Unit), NPU (Neural Processing Unit), Artificial Intelligence Inference Chip, CPU, and other computing chips and devices. The method can remove redundancy and reduce the dependency on carry bit computing. RTC code method can provide a redundancy-tolerated digital coding method for negative and positive integers, and can guarantee that number “0” have one and only one representation.