Larry Ellison, Oracle Corp's outspoken chief, charged that German arch-rival SAP AG stole billions of dollars of his company's copyrighted software.

Ellison made the allegation as the star witness in the US software maker's software-theft lawsuit, which is captivating Silicon Valley.

SAP, Europe's largest software company, has admitted to liability for theft of Oracle software files by a now-defunct subsidiary, TomorrowNow. The two companies are fighting it out in a federal courtroom in California to determine how much the German company should compensate Oracle.

Three and a half years after Oracle filed its lawsuit, Ellison -- famous for his no-holds-barred attacks on SAP -- is finally getting the chance to argue his case that the German company should cough up billions of dollars. SAP says it should pay only tens of millions of dollars.

He began his testimony by giving a brief history of Oracle, the world's No. 3 software company and biggest maker of database software, which he co-founded in 1977 and now has more than 100,000 employees.

Ellison said that Oracle would come close to going out of business if his company's software were not protected by copyright laws. Oracle spends several billions of dollars a year on product development.