JPS5617452A - Ring protection system - Google Patents
Ring protection systemInfo
- Publication number
- JPS5617452A JPS5617452A JP9352079A JP9352079A JPS5617452A JP S5617452 A JPS5617452 A JP S5617452A JP 9352079 A JP9352079 A JP 9352079A JP 9352079 A JP9352079 A JP 9352079A JP S5617452 A JPS5617452 A JP S5617452A
- Authority
- JP
- Japan
- Prior art keywords
- output
- generates
- user
- comp
- limit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
PURPOSE: To prevent a user program from destroying a program in a system space by mistake by employing a limit register system for a ring protection system and then by making it effective only in a user's area.
CONSTITUTION: In the 1st and 2nd limit registers LR0 and LR1, upper limit and lower limit segment numbers SN0 and SN1 of the user's area of a user program in run mode at that time are written, and comparators COMP1 and COMP2 receive those segment number at one-side input terminals and segment number SN of address LA, to which the next access is attained, at the other-side input terminals. Comparator COMP1 generates no output when SN0>SN and comparator COMP2 generates no output when SN>SN1. Therefore, while SN0<SN<SN1, OR gate OG generates no output, but while not, an access inhibition output is sent out of OR gate OG.
COPYRIGHT: (C)1981,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP9352079A JPS5617452A (en) | 1979-07-23 | 1979-07-23 | Ring protection system |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP9352079A JPS5617452A (en) | 1979-07-23 | 1979-07-23 | Ring protection system |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS5617452A true JPS5617452A (en) | 1981-02-19 |
Family
ID=14084599
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP9352079A Pending JPS5617452A (en) | 1979-07-23 | 1979-07-23 | Ring protection system |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5617452A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57195394A (en) * | 1981-05-23 | 1982-12-01 | Nippon Telegr & Teleph Corp <Ntt> | Memory protection system by processor |
JPS60120451A (en) * | 1983-12-05 | 1985-06-27 | Fujitsu Ltd | Memory protection in unit of word |
-
1979
- 1979-07-23 JP JP9352079A patent/JPS5617452A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57195394A (en) * | 1981-05-23 | 1982-12-01 | Nippon Telegr & Teleph Corp <Ntt> | Memory protection system by processor |
JPS60120451A (en) * | 1983-12-05 | 1985-06-27 | Fujitsu Ltd | Memory protection in unit of word |
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