| 摘要 |
PATENTS 83-397 The invention is an apparatus and/or method which enables one to divide two elements, A and B, of GF(22M), that is, perform the operation B/A, by finding the multiplicative inverse of the divisor A, and then multiplying the inverse by the numerator, B. The multiplicative inverse, A-1, of A is found by computing a conversion factor, D, and then multiplying A by D to convert it to an element C, where C is also an element of a smaller Galois Field, GF(2M), which is a subfield of GF(22M). Specifically, C is equal to A2M+1, or A2M*A, in the field GF(22M). Next, the multiplicative inverse, C-1, of C in GF(2M) is found by appropriately entering a stored look-up table containing the 2M elements of GF(2M). The multiplicative inverse, C-1, of C is thereafter converted, by multiplying it by the conversion factor D calculated above, to the element of GF(22M) which is the multiplicative inverse, A-1, of the original divisor, A. The multiplicative inverse, A-1, of A is then multiplied by B to calculate the quotient, B/A. |
