Method for virtually enlarging the stack of a portable data carrier

US7000071B2 · kind B2 · utility

Assignee

• GIESECKE & DEVRIENT GMBH · DE

Inventors

• Daniel Ciesinger · Birkenfeld, DE
• Thomas Frey · Ebersberg, DE
• Martin Merck · Hersbruck, DE
• Thomas Stocker · Wolfsburg, DE

Key dates

• Filing date: Aug 21, 2001
• Grant date: Feb 14, 2006
• Expiry date: May 20, 2022

Classification

• Technology area (CPC G): Physics
• CPC primary: G06Q20/3552
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A method is proposed for virtual enlargement of the stack of a portable data carrier allowing reloading of executable program code. To permit the execution of programs requiring a larger stack than that physically present, the stack is segmented into at least two stack segments and their fill state monitored. When complete occupation of a segment is recognized, the oldest stack segment is swapped out to a further storage medium. The further storage medium is a nonvolatile read-write memory that can be a slower memory compared to the stack. When sufficient memory space is available in the stack again, the swapped out segment is returned. The method includes managing a destination address of each stack segment swapped out to the non-volatile read-write memory in a register in a volatile read-write memory.