Sharad N Gandhi, 8519018 Bechard Ave, Artesia, CA 90703

4691277, Sep 1, 1987

Oct 24, 1984

6/664275

Eric P. Kronstadt - Westchester County NY
Tushar R. Gheewala - Los Angeles CA
Sharad P. Gandhi - Santa Clara CA

International Business Machines Corp. - Armonk NY

G06F 1314

364200

A branch target table (10) is used as an instruction memory which is referenced by the addresses of instructions which are targets of branches. The branch target table consists of a target address table (12), a next fetch address table (14), valid entries table (16) and an instruction table (18). Whenever a branch is taken, some of the bits in the untranslated part of the address of the target instruction, i. e. the instruction being branched to, are used to address a line of the branch target table (10). In parallel with address translation, all entries of the branch target table line are accessed, and the translated address is compared to the target address table (12) entry on that line. If the target address table entry matches the target address, the instruction prefetch unit (32) fetches the instruction addressed by the next fetch address table (14) entry for the given line and the line of instructions associated with the branch address table entry is read into an instruction queue (38) having a length set by the valid entry table ( 16) entry which indicates how many of these instructions are valid. Otherwise, the instruction prefetch unit (32) fetches the target and subsequent instructions as it would if there were no branch target table, and the target address table entry is set to the real address of the target instruction.