Patent ID: 6462694
Filing Date: 2002-10-08
Classification: G06F

Abstract:
A priority encoder which outputs a (m+n)-bit code corresponding to the number of the highest-priority input line among a plurality of input lines having a true value when true values are input to more than one of 2m+n input lines which are numbered and prioritized on the basis of their numbers, comprising:higher-order-bit encoding means for outputting a higher-order m-bit code corresponding to the group having the highest priority among those groups out of 2m groups distinguished by higher-order m bits to which true values are input (hereinafter referred to as â€œhighest-priority group distinguished by the higher-order m bitsâ€ ); each of said 2m groups consisting of 2n input lines having common higher-order m bits of (m+n)-bit output code; and lower-order-bit encoding means for outputting a lower-order n-bit code corresponding to the input line having the highest priority among input lines to which true values are input, said lower-order-bit encoding means comprising means for invalidating the input of true values into input lines to groups having lower priorities than the highest-priority group distinguished by the higher-order m bits; said input lines being part of 2n input lines which are distinguished by the lower n bits of the (m+n)-bit output code.