1. A computer for effecting parallel processing, said computer using an instruction system having instruction words, each instruction word having a plurality of operation field groups, each operation field group including at least one operation field, said computer comprising: a plurality of register files, each respectively provided in association with one of said operation field groups and each designated as an operand only in said associated operation field group; and a path connecting one of said register files which is designated as an operand of one of said operation field groups to another of said register files which is designated as an operand of a different one of said operation field groups, wherein data is transferred between said register files on said path based on an operation in one of said operation fields of said instruction words.