Method and apparatus for using condition codes to nullify instructions based on results of previously-executed instructions on a computer processor
US5815695A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Sep 29, 1998 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/323
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The invention is a method and apparatus for conditionally nullifying a current instruction based on a first test value where the first test value can be set in one or more prior instructions and where the execution of the current instruction can set a second test value without affecting the first test value. The one or more prior instructions which set the first test value need not immediately precede the current instruction. In a preferred embodiment, a test value comprises multiple bits, each bit capable of representing a unique state. A mask is provided to select the bits which are being tested. Also, means are provided for specifying an logical operation to be performed on the test values. The invention permits multiple status test results to be saved and concurrently tested in a single branch instruction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.