| 摘要 |
<p>The present invention basically consists in the use of a separate redundant read bus (37) fully dedicated to redundancy fed by a single spare sub-array (34'-1) which is common to all the memory sub-arrays (34-1, ...) of the cache memory (33). As a result, the redundant sense amplifiers (35'-1, ...) are no longer dotted with the normal sense amplifiers (35-1, ...) on a common read bus. The redundant sense amplifiers (35'-1) are dotted to the said redundant read bus (37) and the normal sense amplifiers (35-1, ...) are connected to a main read bus (36) comprised of 4 read busses (36-0, ...) in case of a 4-way set associative cache memory organization. Consequently, both the normal and redundant 32 data are valid and available at the same time at the outputs of the normal and redundant sense amplifiers, i.e., on the main and redundant read busses respectively. When the two late select address signals LS0 and LS1 become valid, then the correct information, i.e. the correct 8 data among said 32 to be output, can be immediately selected via a 1/4 multiplexer (39) provided with an INHIBIT (INH) input. The multiplexer (39) is normally controlled by the four decoded signals (derived from said two late select address signals) generated by a decoder (40) unless redundancy is required. In this case, the information generated by the bit address comparator 44 and stored in a latch (46), combined with the information generated by a late select address comparator (43) forces the multiplexer via said INHIBIT input, to select the redundant read bus instead of one read bus of the main read bus, to output the redundant byte as the selected one. <IMAGE></p> |
