Method and apparatus for modifying instruction operations in a processor
US6321380A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 1999 |
| Grant date | Nov 20, 2001 |
| Priority date | — |
| Expiry date | Jun 29, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/328
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A "soft-patch" allows an instruction or group of instructions to be replaced with a pre-loaded instruction or group of instructions. When an Instruction Fetch Unit (IFU) fetches an instruction, the instruction is sent through a Compare and Mask (CAM) circuit which masks and compares, in parallel, the instruction with up to eight pre-defined masks and values. The masks and values are pre-loaded by a service processor to CAM circuits which are located in an Instruction Dispatch Unit (IDU) and the IFU in the central processor. An instruction that is deemed a match, is tagged by the IFU as a "soft-microcode" instruction. When the IDU receives the soft-microcode instruction for decoding, it detects the soft microcode marking and sends the marked instruction to a soft-microcode unit; a separate parallel pipeline in the IDU. The soft-microcode unit then sends the instruction through a CAM circuit which returns an index (or address) for RAM. The index is used to read values out of IDU RAM and generate replacement instructions. Additionally, an Internal Operation that will cause the processor core to perform an unconditional branch to a fixed real address, can be loaded into the IDU RAM all…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.