| 摘要 |
<p>The present invention provides a data processing system for performing an arithmetic operation on a plurality 'p' of signed 'n-bit' data values, and a method of operating such a data processing system. The technique of the present invention involves encoding the plurality of signed n-bit data values as a composite value comprising p n-bit fields by performing an encoding operation equivalent to aligning each signed data value with a respective n-bit field, sign extending each signed data value to the most significant bit of the composite value, and adding the aligned and sign extended data values to form the composite value. Then the arithmetic operation is applied to the composite value to produce an encoded result comprising p n-bit fields, and the encoded result is decoded to produce p final results by applying a decoding operation equivalent to extracting the data from each n-bit field of the encoded result and correcting for any effect caused by the addition of an adjacent sign extended data value during the encoding step, whereby each final result represents the application of the arithmetic operation to a corresponding signed n-bit data value. In accordance with the present invention, two or more signed data values are encoded into a composite value, and the composite value is then processed using standard instructions as if they were SIMD instructions. This is made possible by use of a particular encoding of the signed data values which avoids the problems with overflow and underflow between two adjacent data values. Since this encoding enables standard instructions to be used, much of the benefits of using SIMD extensions can be achieved without the cost of extra hardware or new instructions which SIMD techniques necessitate.</p> |
