International Business Machines Corporation

Werner Buchholz

Ronald M Smith

David S Wehrly

A vector processor is disclosed which processes vectors that can have more elements than a vector register can contain at one time. Vectors are processed in sections in which the section size is determined by the number of element locations in a vector register. A vector count register controls the number of elements processed by each vector instruction. A vector interruption index points to the first or next element in a vector to be processed by a vector instruction either when it is first issued or when it is re-issued following an interruption of the vector instruction. A general purpose (length) register contains the entire length of the vector to be processed. A single instruction, which starts a vector sectioning loop, provides for the smaller of the section size or the content of the length register to be loaded into the vector count register. During the operation of the sectioning loop, the vector count register is repetitively subtracted from the content of the first general purpose register and the resulting residual vector length is placed back in the first general purpose register until all of the elements have been processed.

Vector processing

The invention relates to vector registers (VRs) which have associated therewith a vector status register (VSR) that includes VR status information in the form of vector in-use and change bits for saving and restoring (the contents of) the VRs. When the vector in-use bit for a VR is zero, the saving and subsequent restoring of the VR is eliminated because the VR is known to contain all zeros. This reduces program switching time. The vector change bit for a VR serves to reduce switching time still further by permitting the saving of a VR to be eliminated when its vector in-use bit is one but the vector change bit is zero. Although such a VR is in use, its content has not been changed since the last restore from the same save area in storage. The previously saved information is still valid. The vector change bits do not affect the restoring of vector registers and, therefore, do not reduce the restore time.

Growing community of inventors

Wappingers Falls, NY, United States of America

Werner Buchholz