Method for patching ROM instructions in an electronic embedded system including at least a further memory portion
AssigneeIncard S.A.
InventorsGuido D'Albore, Pasquale Vastano
Life of this patent
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Abstract
A mechanism for patching read only memory (ROM) instructions in an embedded system is provided. The embedded system includes non-volatile memory such as a ROM, a RAM and an EEPROM. In one configuration, the ROM contains application modules (subroutines) that are subordinate to a flag status. The flag status indicates to the subroutine whether to execute the ROM instructions in the ROM or the extended instructions in the EEPROM. The instructions in the EEPROM may be used to patch or to extend the behaviors masked in the ROM instructions. The extended instructions in the EEPROM may reuse the ROM instructions in the ROM without resulting in recursive actions.
Claims26
A method for patching read only memory (ROM) instructions in an electronic system comprising a first nonvolatile memory portion storing instruction groups defining patching functionalities, an extended memory portion storing extended instructions, and an additional memory portion, the method comprising:
- checking a flag stored in the additional memory portion, the flag indicating a need for executing the extended instructions in the extended memory portion;
- and
- alternating processing of the ROM instructions in the first non-volatile memory portion and the extended instructions in the extended memory portion based upon the flag;
- the flag representing binary information associated to a subroutine to indicate whether the subroutine is in one of a free state and a busy state, the subroutine using patching mechanism defined by the ROM instructions, with each patching mechanism having a respective flag associated therewith.
A method for patching ROM instructions in an electronic system comprising:
- storing ROM instructions defining patching functionalities of the electronic system in a read only memory;
- storing extended instructions with respect to the read only memory in an extended non-volatile memory;
- storing flags in an additional memory for indicating a change in the ROM instructions or the extended instructions being executed;
- and
- alternating processing of the ROM instructions in the read only memory and the extended instructions in the extended non-volatile memory based upon a logic value of the flags;
- the flags representing binary information associated to a subroutine to indicate whether the subroutine is in one of a free state and a busy state, the subroutine using a patching mechanism defined by the ROM instructions, with each patching mechanism having a respective flag associated therewith.
An electronic system comprising:
- a read only memory for storing ROM instructions defining patching functionalities of the electronic system;
- an extended non-volatile memory for storing extended instructions with respect to said read only memory;
- an additional memory for storing flags indicating a change in the instructions being executed;
- and
- a processor connected to said read only memory, said extended non-volatile memory and said additional memory, said processor alternating processing of the ROM instructions in said read only memory and the extended instructions in said extended non-volatile memory based upon the flags;
- the flags representing binary information associated to a subroutine to indicate whether the subroutine is in one of a free state and a busy state, the subroutine using patching defined by the ROM instructions, with each patching mechanism having a respective flag associated therewith.
Dependencies are inferred from the claim text.