Data processing device for variable length multibyte data fields

A device for processing multibyte data fields of variable length, comprising:

• a control unit, for controlling the cooperation of units of the device during the processing of multibyte data fields, having a multichannel output and first, second, third and fourth outputs;
• a storage unit, for storing operands, intermediate results and processing results, having an input, a control input, a first data input, a second data input, a first data output and a second data output, said control unit input of said storage unit being coupled to said first output of said control unit;
• a first data exchange bus coupled to said first data input and to said first data output of said storage unit;
• a second data exchange bus coupled to said second data input and to said second data output of said storage unit;
• a data shift unit, for shifting the alignment of the data fields fed from the exchange buses in accordance with signals from said control unit, providing with a multichannel control input, first, second, third and fourth data inputs and first and second data outputs, said multichannel control input of said data shift unit being coupled to said multichannel output of said control unit, said first data input, said third data input and said first data output of said data shift unit being coupled to said first data exchange bus, and said second data input, said fourth data input and said second data output of said data shift unit being coupled to said second data exchange bus;
• a first switch having first and second inputs, a multichannel input and an output, said first input of said first switch being coupled to said first data exchange bus;
• a second switch having first and second inputs, a multichannel input and an output, said first input being coupled to said second data exchange bus,
• said second input of said first switch and said second input of said second switch being coupled to said second output of said control unit;
• a data masking unit, for blanking out insignificant data within a data word, having a control input coupled to said third output of said control unit, a first input coupled to said first data exchange bus, a second input coupled to said second data exchange bus, and a multichannel output coupled to said multichannel inputs of said first and second switches;
• and
• an arithmetic/logic unit, for performing arithmetic and logical operations on said data, having a control input coupled to said fourth output of said control unit, a first input coupled to said output of said first switch, a second input coupled to said output of said second switch, and an output coupled to said input of said storage unit.