
Chipworks Disassembles Apple's A8 SoC: GX6450, 4MB L3 Cache and More - zdw
http://www.anandtech.com/show/8562/chipworks-a8
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justincormack
There is also a core for security in there somewhere running an L4
microkernel, as described in the security guide[1] page 7

[1]
[http://images.apple.com/privacy/docs/iOS_Security_Guide_Sept...](http://images.apple.com/privacy/docs/iOS_Security_Guide_Sept_2014.pdf)

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MrBuddyCasino
Wow, thats news to me. Its been there since the A7 apparently and is used to
process the fingerprint sensor data:

"The Secure Enclave uses encrypted memory and includes a hardware random
number generator. Its microkernel is based on the L4 family, with
modifications by Apple. Communication between the Secure Enclave and the
application processor is isolated to an interrupt-driven mailbox and shared
memory data buffers.

Each Secure Enclave is provisioned during fabrication with its own UID (Unique
ID) that is not accessible to other parts of the system and is not known to
Apple. When the device starts up, an ephemeral key is created, entangled with
its UID, and used to encrypt the Secure Enclave’s portion of the device’s
memory space."

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petermonsson
They found CPU, GPU and cache. What is in the remaining 40% of the chip? There
are a lot of individual blocks in there.

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MCRed
This is where Apple really adds value and why they have their own silicon
design teams.

Some of the blocks:

\-- M7 motion chip

\-- Image processing chip to support camera

\-- (I suspect) audio processing chip to do compression and feature extraction
for SIRI

\-- (suspect) video codec (though this may be done by GPU)

\-- Secure Enclave -- CPU with secure data, random number generator, Apple Pay
support, Fingerprint Sensor support

\-- (I suspect) memory management units and io co-processors and the like that
are too mundane to get much public mention

~~~
nilsimsa
The motion chip is a separate package.

~~~
joezydeco
Chipworks decapped the M7 on the iphone5 and found it to be a custom model of
the LPC18xx from NXP

[http://www.chipworks.com/en/technical-competitive-
analysis/r...](http://www.chipworks.com/en/technical-competitive-
analysis/resources/blog/inside-the-iphone-5s/)

[http://www.nxp.com/products/microcontrollers/cortex_m3/lpc18...](http://www.nxp.com/products/microcontrollers/cortex_m3/lpc1800/)

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coldpie
If these kind of raw IC photos interest you, here's a couple links describing
what you're looking at:

"The 6502 CPU's overflow flag explained at the silicon level"

[http://www.righto.com/2013/01/a-small-part-of-6502-chip-
expl...](http://www.righto.com/2013/01/a-small-part-of-6502-chip-
explained.html)

And a handful of links by other HN members about how to interpret silicon-
level images:

[https://news.ycombinator.com/item?id=7481973](https://news.ycombinator.com/item?id=7481973)

