Signed/unsigned integer guest compare instructions using unsigned host compare instructions for precise architecture emulation
US7752028B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 2007 |
| Grant date | Jul 6, 2010 |
| Priority date | — |
| Expiry date | Jul 3, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/45537
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Architecture for efficient translation and processing of PowerPC guest instructions on an x86 host machine. In an x86-based architecture, signed integer values are projected into the unsigned integer value space for processing by the host using the negation of the left-most (sign) bit. Compare operations are performed in the unsigned space and the compare results are written into the host flags register. Once the compare results are written into the host flags register, the flag values can be read out and used in a table lookup to retrieve the corresponding values for the guest register. The guest flag values are then passed into the guest flags register for processing by the guest application.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.