PURPOSE: To perform a test of the internal state of a device with a small quantity of hardware resources and to reflect the result of this test on the branch of a microinstruction by scanning out by one bit an optional register contained in the device corresponding to the address set at a scan address register and stopping the operation of the device in response to the scan output.
CONSTITUTION: The value of a latch having an address corresponding to the contents of a register 7 set by a microinstruction or the instruction of an SVP 25 is used as the input of a test circuit 20 via a signal line 23. The circuit 20 compares the value designated by the microinstruction with the value of the line 23 and outputs the result of this comparison as the input of a branch circuit 24. The circuit 24 controls the branch of a microprogram based on the output of the circuit 20. Thus it is possible to test an optional latch having a scan route by the microinstruction and to reflect the test result on the branch of the microprogram. Then various types of tests can be carried out with use of a small quantity of hardware.
| JPS57111744 | MICROPROGRAM CONTROL SYSTEM |
| JPS5642855 | DATA PROCESSOR |
YAMASHITA MASAHIRO
SATO TADASHI
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