Decimal Floating Point Composition from Significand and Biased Exponent

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Solution Overview

Problem

Existing technologies face challenges in converting data from human-readable decimal formats to decimal floating point formats without loss of accuracy, particularly in processing environments where intermediate data types like signed packed decimal and signed binary integer are used.

Innovation Solution

A method is provided to compose decimal floating point data by obtaining the significand and exponent in separate formats, converting the significand to decimal floating point format, and combining it with a biased exponent to create the decimal floating point format, using specific instructions and logic to facilitate this conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If binary floating point is used to represent real numbers in computer hardware, then the data can be processed efficiently in binary format, but it cannot accurately represent some decimal fractions (like 0.1) and requires rounding during scaling operations

Engineering Contradiction:

Improveaccuracy of decimal fraction representationVSAvoidease of comprehension and human readability

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent changes the radix parameter from binary (base 2) to decimal (base 10) in the floating point representation system. This allows decimal fractions to be represented exactly without rounding errors, while maintaining efficient computer processing through specialized decimal floating point hardware instructions that operate on packed decimal data formats.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If decimal floating point format is used to accurately represent decimal numbers, then measurement precision is improved, but the device complexity increases due to the need for specialized conversion and composition logic

Engineering Contradiction:

Improveaccuracy of decimal number representationVSAvoidcomplexity of conversion logic from intermediate formats

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the decimal floating point number into distinct components: sign bit, exponent field, and significand field. Each component is processed and converted separately through specialized instructions, which simplifies the overall conversion process from intermediate formats like signed packed decimal and signed binary integer to the final decimal floating point format.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses packed decimal format as an intermediary representation during the conversion process. Data is first converted to packed decimal, then to signed binary integer for exponent processing, and finally composed into the decimal floating point format. This intermediary approach simplifies the complex direct conversion by breaking it into manageable stages with well-defined transformation rules.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If data is converted from human-readable decimal format to intermediate formats (signed packed decimal and signed binary integer), then the data can be processed in the processing environment, but loss of accuracy may occur during the conversion process

Engineering Contradiction:

Improveprocessing capability in computing environmentVSAvoidaccuracy of data representation

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary conversion of the significand to packed decimal format and the exponent to signed binary integer format before processing. This preliminary action ensures that the data is in the correct format for subsequent processing operations while maintaining accuracy through controlled conversion processes that preserve the numerical value.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent incorporates feedback mechanisms in the conversion process where the system monitors the conversion from intermediate formats to decimal floating point format and adjusts the composition logic to ensure accuracy is maintained. The feedback ensures that rounding errors are minimized and that the final representation accurately reflects the original human-readable input.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS8060545B2Composition of decimal floating point data, and methods therefor

Publication Date: 2011.11.15 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A decimal floating point finite number in a decimal floating point format is composed from the number in a different format. A decimal floating point format includes fields to hold information relating to the sign, exponent and significand of the decimal floating point finite number. Other decimal floating point data, including infinities and NaNs (not a number), are also composed. Decimal floating point data are also decomposed from the decimal floating point format to a different format.