Dynamic alteration of firmware programs in Read-Only Memory based systems
US4607332A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 14, 1983 |
| Grant date | Aug 19, 1986 |
| Priority date | — |
| Expiry date | Jan 14, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/268
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for dynamically altering Read-Only Memory (ROM)-based programs utilizes Random-Access Memory (RAM) and standard processor linkages associated with subroutine or function calls. Each original ROM program includes a statement to call a ROM processing routine. If information passed to the processing routine by the original routine indicates a RAM-based replacement routine is to be executed for the original routine, the processing routine (i) restores the processor to its state immediately following the call to the processing routine, and (ii) branches directly to the replacement routine at a location provided by a RAM-based data structure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.