Read-only access to CPO registers
US7181600B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 2, 2001 |
| Grant date | Feb 20, 2007 |
| Priority date | — |
| Expiry date | Jul 15, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/4812
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A bit mask register is provided within the privileged architecture of a microprocessor. The bit mask register includes a plurality of bits, the bits corresponding to other privileged architecture registers. When a bit in the bit mask register is set, its corresponding privileged architecture register is made read-only accessible when the microprocessor is in user mode. When a bit in the bit mask register is clear, its corresponding privileged architecture register is unavailable when the microprocessor is in user mode. If an instruction executing in user mode requests access to a privileged architecture register, and its corresponding bit in the bit mask register is clear, an exception is generated, allowing a kernel mode operating system to optionally set the corresponding bit in the bit mask register, and provide read-only access to the register.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.