04875156 is referenced by 13 patents and cites 10 patents.

In a computer having a program including a first type of instruction and a second type of instruction, a program memory has a first area for storing the first type of instruction and a second area for storing the second type of instruction. An address code is supplied from a program counter to the program memory, which thereby produces an instruction code stored at the addressed memory location. A control unit is responsive to the instruction code from the program memory for producing a control signal for controlling the operation of the computer. A protection circuit is provided for preventing execution of the first type of instruction when the address code output from the program counter does not designate any memory location in the first area.

Title
Computer having a protection device to selectively block incorrect control signals
Application Number
7/22062
Publication Number
4875156
Application Date
March 3, 1987
Publication Date
October 17, 1989
Inventor
Tomoaki Yoshida
Tokyo
JP
Kouji Tanagawa
Tokyo
JP
Agent
Spencer & Frank
Assignee
Oki Electric
JP
IPC
G06F 11/00
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