Sum Addressed Decoder - Match Generation

Match Generation

I	even bank fetches line	odd bank fetches line
100	100	101
101	110	101
110	110	111

Referring to the diagram to the right, we can see that the even bank will fetch line 110 when I==101 or I==110. The odd bank will fetch line 101 when I==100 or I==101.

In general, the odd SRAM bank should fetch line Lo==2N+1 when either I==2N or I==2N+1. We can write these two conditions as:

I = Lo-1 => R + O + ~Lo+1 = 11..11 => R + O + ~Lo = 11..10 I = Lo => R + O + ~Lo = 11..11

We ignore the last digit of the compare: (S+C)==11..1

Similarly, the even SRAM bank fetches line Le==2N when either I==2N or I==2N-1. We can write these two conditions as follows, and once again ignore the last digit of the compare.

I = Le-1 => R + O + ~Le = 11..10 I = Le => R + O + ~Le = 11..11