Method and apparatus for runtime remediation of object-code instructions in a computer program
US6708180B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 14, 1998 |
| Grant date | Mar 16, 2004 |
| Priority date | — |
| Expiry date | Sep 30, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99944
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for runtime remediation of object-code instructions (such as date instructions that are not year 2000 compliant) in a computer program. Before runtime, a setup function of a program monitor locates each instruction to be remediated in a load module of a user program and overlays the instruction with a trap instruction. The address of the overlaid instruction is stored in a scan slot of a window control table (WCT). The text of the overlaid instruction is stored in a corresponding operand slot of the WCT along with control information including a set of flags and windowing and cycling parameters. At runtime, upon decoding a trap instruction, the CPU transfers control to an instruction simulation function of the program monitor, which searches the scan slots of the WCT for the one containing the address of the overlaid instruction. Upon finding the scan slot, the instruction simulation function performs an instruction simulation operation in accordance with the control information in the corresponding operand slot, then returns control to the user program. If an execute flag is not set, the instruction simulation function invokes a specified user routine withou…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.