The way I understand this is that anyone who got ARM documentation with the license that Paul mentioned, could not contribute patches that implement v6 emulation. If, however, someone else (who has not signed such a license) were to buy documentation about the ARMv6 architecture that comes without a license (for example, the "ARM System Developer's Guide", by Sloss, Symes, and Wright, Elsevier 2004), that someone should be able to contribute (at least in those aspects of the ARM that are disclosed by the book). In that case, ARM should not have any legal hooks except copyright, and since at that point you are not using any of their code, there is no case. However, I am not a lawyer, so don't take my word for it.
As to the threats to ARM's business model, I could see them threatened if someone emulated the ARM on hardware of similar performance (without licensing ARM IP) -- that would undermine sales of the real ARM cores, depending on the price/performance point of the replacement. Software emulation of an ARM core on a 4 GHz Pentium is hardly an alternative to buying the real thing, though... I also find it hard to believe that building a product competitive to an ARM is possible using a description of the instruction set alone. That said, I agree with Paul that lobbying ARM to change their license is probably a better route to go. I believe software emulators like qemu are really in ARMs best interest since they support ARM development and thereby increase the availability of software for ARM cores. - Wolfgang Disclaimer: The views stated above are entirely mine, and do not necessarily reflect the views of my employer. Paul wrote on 30.03.2006 00:01:41: > > I could understand a claim if someone acquired ARM's documentation > > under an agreement to not produce an emulator. > > That's exactly where the restriction comes from. > > Theoretically it may be possible to reverse engineer a good proportion of > ARMv6 from other sources (eg. gcc). However if that were done it would mean > anyone with access to the real ARM documentation (i.e. me and probably anyone > else with any professional/commercial interest in ARM emulation) would be > unable to contribute to qemu. > > > And if there is a possibility of that - in which countries do they > > have any weight? Dare I suggest encouraging the development of > > patches they don't like to countries where they have no legal weight? > > I don't think that's particularly helpful or practical suggestion. > Better would be to lobby ARM to allow open source emulators. > "I'd like to use ARM hardware for <big project>, but qemu doesn't support > ARMv7 so I'm thinking of using PowerPC instead" is a particularly good > argument ;-) > > Paul > > > _______________________________________________ > Qemu-devel mailing list > Qemu-devel@nongnu.org > http://lists.nongnu.org/mailman/listinfo/qemu-devel -- Wolfgang Schildbach, Senior Research Engineer Coding Technologies GmbH _______________________________________________ Qemu-devel mailing list Qemu-devel@nongnu.org http://lists.nongnu.org/mailman/listinfo/qemu-devel
