| 摘要 |
PROBLEM TO BE SOLVED: To prevent an infinite loop which continues to perform breakpoint operation at every time by inhibiting a breakpoint signal for a next instruction from being generated when a CPU restarts operating normally after interruption for a diagnosis. SOLUTION: A CPU 162 has an executing circuit 411 which executes instructions in a memory 164 and an instruction pointer register 406 which holds the address of an execution instruction. A breakpoint unit 400, on the other hand, is connected to the register 406 and has breakpoint registers 402 and 404. The registers 402 and 404 compare their held breakpoint addresses with the contents of the register 406 and output a breakpoint signal when obtaining a match. When execution control logic 454 receives the signal, the normal operation of the CPU 162 is interrupted for a diagnosis. The breakpoint unit 400 has a circuit which inhibits the generation of a breakpoint signal of a next instruction regarding the start of the normal operation of the CPU after the interruption. |
