In a set-associative cache, the result of the 
comparisons must be used
to select which of the possible data blocks are to be sent out of the
cache. Since the width of a block (8B) is usually greater than the cache
output width ( 
), it is also necessary to choose part of the selected
block to drive the output lines. An A-way set-associative cache contains
A multiplexor driver blocks, as shown in Figure 6. Each
multiplexor driver uses a single comparator output bit, along with address
bits, to determine which data array outputs drive the output bus.
Figure 6: Overview of data bus output driver multiplexors