Abstract: Disclosed is a digital circuit which comprises input signals A[n?1:0], SH[log2n?1:0], and DAT[n?1:0], a barrel shifter for outputting data B[n?1:0] obtained by shifting the signal DAT by the bits of the signal SH, a group G·P·SUM computation stage for dividing each of the digits of the input signals A and B into groups of m bits, and computing Gs, Ps, and addition results SUM0 when carry inputs are high and addition results SUM1 when the carry inputs are low, a carry computation circuit for computing a carry for each of the groups, and a SUM selection stage for selecting a SUM0 or a SUM1 computed for each of the groups according to each carry output by the carry computation circuit.

Abstract: A cache memory related to the present invention is a cache memory employing a set associative system, for generating a valid bit for showing the presence of validity of a cache data, and comprises a tag memory 1 for storing an address tag of an address of a cache data and a first valid bit for showing the presence of validity of the cache data in a set of blocks in response to an index, and a valid bit register 2 for storing a second valid bit corresponding to the first valid bit, and resetting the second valid bit, and the valid bit is generated based on the first valid bit and the second valid bit.

Abstract: Disclosed is a digital circuit which comprises input signals A[n?1:0], SH[log2n?1:0], and DAT[n?1:0], a barrel shifter for outputting data B[n?1:0] obtained by shifting the signal DAT by the bits of the signal SH, a group G·P·SUM computation stage for dividing each of the digits of the input signals A and B into groups of m bits, and computing Gs, Ps, and addition results SUM0 when carry inputs are high and addition results SUM1 when the carry inputs are low, a carry computation circuit for computing a carry for each of the groups, and a SUM selection stage for selecting a SUM0 or a SUM1 computed for each of the groups according to each carry output by the carry computation circuit.

Abstract: A cache memory related to the present invention is a cache memory employing a set associative system, for generating a valid bit for showing the presence of validity of a cache data, and comprises a tag memory 1 for storing an address tag of an address of a cache data and a first valid bit for showing the presence of validity of the cache data in a set of blocks in response to an index, and a valid bit register 2 for storing a second valid bit corresponding to the first valid bit, and resetting the second valid bit, and the valid bit is generated based on the first valid bit and the second valid bit.