LONDON — As far as I can tell, the teardowns of the Apple iPhone conducted over recent days by Semiconductor Insights and Portelligent have failed to come up with a definitive answer to the "ARM question" — at least so far.

The ARM question is: "How many ARM processor cores does it take to make an iPhone?" and we are inclined to tip our hat to Didier Scemama, semiconductor analyst with ABN AMRO Bank here, who seemed to get most of the iPhone teardown information right, back in January without having to break open a casing.

Scemama's assessment was three ARM processor cores. So that would be an ARM1176 in the Samsung 5L8900, an ARM9 or 7 in the Marvell W8686 wireless LAN chip and a ARM926 in the Infineon PMB8876 S-Gold2 chip. But could there be more?

Of course the reason the teardowns don't answer the 'ARM question' is because it is difficult. Chip vendors and manufacturers don't always advertise their own involvement on chip packaging. And IP vendors rarely get an explicit name check.

So it would be necessary to expose the die and then perform pattern recognition to spot the processor core and identify it by correlation with known examples. Even then their may not be known 1:1 examples if a processor is the first example in a process technology node.

Or maybe there is a better way. Follow the code — as some iPhone and graphics processor afficianados have done (see July 6 story).

An examination of firmware, crash logs and cache dumps can reveal tell-tale references to processors and provide a better way to find out what is going on than simply deconstructing the circuit boards. It would also be interesting to know if the processor used in the Broadcom BCM5973A touch-screen controller in the iPhone was developed in Cambridge, England.

That, along with the XAP 16-bit RISC likely to be inside the CSR 41B14 BlueCore4ROM Bluetooth chip and the PowerVR MBX from Imagination Technologies Group plc rumored to be inside the main Samsung chip would make it Cambridge 5, Kings Langley 1, Rest of the World 0 on the iPhone processor score.