An electronic device (10). The device comprises a memory structure (12)
comprising an integer M of word storage locations. The device further
comprises a write shift register (SR.sub.WT) for storing a sequence of
bits. The sequence in the write shift register comprises a number of bits
equal to a ratio of 1/R.sub.1 times the integer M. The device further
comprises circuitry (16) for providing a write clock cycle to the write
shift register for selected write operations with respect to any of the
word storage locations. In response to each write clock cycle, received
from the circuitry for providing the write clock cycle, the write shift
register shifts the sequence in the write shift register. Further, one
bit in the sequence in the write shift register corresponds to an
indication of one of the memory word storage locations into which a word
will be written. The device further comprises a read shift register
(SR.sub.RD) for storing a sequence of bits. The sequence in the read
shift register comprises a number of bits equal to a ratio of 1/R.sub.2
times the integer M. The device further comprises circuitry (16) for
providing a read clock cycle to the read shift register for selected read
operations with respect to any of the word storage locations. In response
to each read clock cycle, received from the circuitry for providing the
read clock cycle, the read shift register shifts the sequence in the read
shift register. Further, one bit in the sequence in the read shift
register corresponds to an indication of one of the memory word storage
locations from which a word will be read. Lastly, the device comprises
circuitry (18.sub.x) for evaluating selected bits in the sequence in the
write register relative to selected bits in the sequence in the read
register for detecting a level of data fullness in the memory structure.