Memory management method and apparatus for partitioning homogeneous memory and restricting access of installed applications to predetermined memory ranges
US6292874A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 19, 1999 |
| Grant date | Sep 18, 2001 |
| Priority date | — |
| Expiry date | Oct 19, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/145
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A memory management unit is disclosed for a single-chip data processing circuit, such as a smart card. The memory management unit (i) partitions a homogeneous memory device to achieve heterogeneous memory characteristics for various regions of the memory device, and (ii) restricts access of installed applications executing in the microprocessor core to predetermined memory ranges. The memory management unit provides two operating modes for the processing circuit. In a secure kernel mode, the programmer can access all resources of the device including hardware control. In an application mode, the memory management unit translates the virtual memory address used by the software creator into the physical address allocated to the application by the operating system in a secure kernel mode during installation. The memory management unit implements memory address checking using limit registers and translates virtual addresses to an absolute memory address using offset registers. The memory management unit loads limit and offset registers with the appropriate values from an application table to ensure that the executing application only accesses the designated memory locations. The memory…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.