Abstract A serial para lel multiplication device in which the digits of the multiplicand are coded in two''s complement and in which the digits of the multiplier are coded in two''s complement modified by inverting the highest ranking digit and appending another digit of predetermined value as the last digit, the appended digit having the same rank as the lowest ranking digit. The devie produces a series of partial products, each partial product being formed by logically combining the inverse of the ith multiplier digit with each multiplicand digit. As a consequence, each partial product digit assumes one value if the correspondingly ranking multiplicand and ith multiplier digits match and another value if they mismatch. The partial product is then corrected by adding to it the value of the ith digit.
In a serial-parallel multiplication device in which each digit of a multiplicand A (FIG. 3-RA) in two''s complement form is logically combined with a digit of a multiplier X (FIG. 3-RX) also in two''s complement form to yield a partial product; the combination comprising: means (FIGS. 1 or 2) for modifying the multiplier by inverting the highest ranking digit and appending another digit of predetermined value as the last digit, the appended digit having the same rank as the lowest ranking digit; logic means (FIG. 3-I, XOR3 to 6) for inverting each modified multiplier digit and for combinaing the ith modified multiplier digit with each multiplicand digit, each combined digit assuming one binary value if the corresponding ranked multiplicand and ith multiplier digits match and another binary value if they mismatch; and means (FC, FIG. 6) for summing the combined digits and the ith modified multiplier digit to form the partial product.
Claim 2
Dependent Claim
152 words
In a serial-parallel multiplication device in which each digit of a multiplicand A (FIG. 3-RA) in two''s complement form is logically combined with a digit of a multiplier X (FIG. 3-RX) also in two''s complement form to yield a partial product; the combination comprising: means (FIGS. 1 or 2) for modifying the multiplier by inverting the highest ranking digit and appending another digit of predetermined value as the last digit, the appended digit having the same rank as the lowest ranking digit; logic means (FIG. 3-I, XOR3 to 6) for inverting each modified multiplier digit and for combinaing the ith modified multiplier digit with each multiplicand digit, each combined digit assuming one binary value if the corresponding ranked multiplicand and ith multiplier digits match and another binary value if they mismatch; and means (FC, FIG. 6) for summing the combined digits and the ith modified multiplier digit to form the partial product.
Claim 3
Dependent Claim
24 words
In a serial-parallel multiplication device according to claim 1, said device further includes: accumulator means (FIG. 6) for successively shifting and summing partial products.