| 摘要 |
PROBLEM TO BE SOLVED: To provide an address computing method, an address computing unit and an address computing and control unit capable of improving the code utilization ratio of an instruction word. SOLUTION: The address computing unit is composed by using: a register 60 that stores an on/off state of cyclic addressing; a cyclic condition judgement part 24 that makes a judgment on the presence/absence of cycling either from an upper area limit LE to a lower area limit LB or from an upper area limit LB to a lower area limit LE; a cyclic address computing part 42 that computes an cyclic address; an acyclic address computing part 44 that computes an acyclic address; and an AND circuit 62 and a selector 32 that select a cyclic address or an acyclic address according to the presence/absence of the cycling when the cyclic addressing is on, or select the acyclic address when the cyclic addressing is off. COPYRIGHT: (C)2004,JPO
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