BLOCK MATCHING ARITHMETIC DEVICE AND RECORDING MEDIUM READABLE PROGRAM-RECORDED MACHINE

A block matching arithmetic device that implements a block matching arithmetic operation while word data containing plural sets of image data is being input or output. Right-rotate-shifted current block creation means creates right-rotate-shifted current block by rotating a current block in the right direction every two pixels and then stores it into a current block storage section. Left-rotate-shifted reference data creation means creates left-shifted reference area by rotating a reference area in the left direction by one pixels and then stores it into a reference area storage section. A sub-block matching arithmetic means implements a block matching arithmetic operation in parallel every sub-blocks obtained by dividing a block in two strings to obtain sub-block matching data. Sum arithmetic means selects sub-block matching arithmetic data regarding the same motion vector and computes the sum of selected arithmetic data, thus obtaining a block matching arithmetic result.