Array processing with fused multiply/add instruction

摘要

Array processing for carrying out scaled-transform/descaled-inverse-transform procedures on data arrays encoding a visual image or other physical variable makes effective use of fused multiply/add instructions in computer workstations or other digital processors having a fused multiply/add capability. To reconstruct data representative of a physical variable from data originally representative of the variable which had been transformed according to a scaled discrete cosine transform procedure using a predetermined scaling matrix Q, an inverse transform procedure of the invention involves computing a descaling constant and a sequence of descaling/inverse-transform matrices which incorporate elements of the scaling matrix Q. One point of the input data array is multiplied by the descaling constant. The result is matrix multiplied by the sequence of descaling/inverse-transform matrices in turn. The descaling-inverse-transform matrices have the property that each matrix multiplication can involve arithmetic operations of exclusively fused signed multiply/add operations, which can be carried out with great efficiency on a computer workstation with fused signed multiply/add capability.