High speed multiplier

A high speed multiplier circuit for performing multiplication of a multiplier and a multiplicand stored in first and second registers, respectively, and storing a product result in a third register for fixed-point data and in said third and first registers for floating-point data, comprising:

• recording means connected to said first register for recording a multiplier stored in said first register to generate control signal outputs;
• preshift means connected to said second register for shifting said multiplicand left for fixed-point data;
• shift gate means connected to outputs of said preshift means and controlled by control signal outputs of said recording means to output selected groups of bits of the multiplicand;
• carry-save adder means connected to outputs of said shift gatemeans for adding a group of multiples of said multiplicand to generate carry and sum output signals;
• spill adder means connected to low order outputs of said carry-save adder means for generating a low order portion of a final result of said multiplication;
• storage means for temporarily storing said low order portion of said final result;
• low-order bus means for transferring said low order portion of said final result to said first register during floating-point operations;
• carry-propagate adder means for generating a high order portion of said final result from high order carry and said sum output signals of said carry-save adder means;
• high order product bus means for transferring said high order portion of said final result to said third register;
• multiplier residue generator means connected to said first register for generating a multiplier residue;
• fixed-point, halfword multiplicand residue generator means connected to said second register for generating a multiplicand residue;
• residue generator means receiving an output from said carry-propagate adder means for generating a sum residue;
• multiplicand residue storage means selectively storing output from one of said fixed-point, halfword multiplicand residue generator means and said residue generator means;
• spill adder residue generator means connected to said storage means for generating a spill adder residue;
• and
• residue calculation means connected to said multiplier residue generator means, said multiplicand residue storage means, said residue generator means and said spill adder residue generator means for generating a residue checking output indicating whether an error has been detected.