公开(公告)号：JPH10301779A

公开(公告)日：1998-11-13

申请号：JP12005598

申请日：1998-04-14

Applicant: MOTOROLA INC

Inventor： JAMES W GIRADOU JR ,  NICOLE D TATELER

IPC: G06F9/38

Abstract: PROBLEM TO BE SOLVED: To fetch single and double word instructions, and to issue two single word instructions to be simultaneously executed in a simple constitution. SOLUTION: An instruction fetch and issue unit 200 fetches two instruction words, and issues at least one instruction word to an instruction decoder 250 in each clock cycle. Two multiplexes 220 and 230 receive the two fetched instructions, and one or both of two words among three words are stored in an instruction register 240. A controller 210 selectively controls the load of the three words among from the inputs of the multiplexers 220 and 230 to the instruction register 240 according to a state figure (207-209). The instruction register 240 issues two instructions at most in each clock cycle without requesting any stall, and efficiently issues double word instructions or parallel two instructions.