What instruction set architecture (ISA) is RDRAND and RDSEED part of?

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I need to acquire a CPU with the RDSEED instructions for testing. As I work through the datasheets for Intel CPU's, it appears that AVX is the latest instruction set called out. See for example, an i5 CPU and an i7 CPU datasheet.

However, I have a MacBook Pro with an i7 with the AVX instruction set, but lacks both RDRAND and RDSSED. So I feel like I'm missing an important detail somewhere.

What instruction set architecture (ISA) is RDRAND and RDSEED part of? Or, what part of the spec should I be looking at to determine if a CPU has RDRAND and RDSEED?

(I realize RDRAND and RDSSED were introduced at different times. I just don't know how to determine a CPU with the feature).

jww

Posted 2015-11-12T11:41:57.880

Reputation: 1

You have to tell us what processor you have. You linked to products separated by 2 years and 2 different generations. This information might not seem important but it might help us answer the question. – Ramhound – 2015-11-12T11:52:07.790

1@Ramhound - I don't have the processor. I need to buy a machine with a CPU that has RDRAND and RDSEED, and I'm trying to determine the processor it needs to fulfill the requirements. – jww – 2015-11-12T11:56:07.377

" I have a MacBook Pro with an i5 that lacks both RDRAND and RDSSED." - I was asking you provide specifics about this. – Ramhound – 2015-11-12T12:00:18.863

RDRAND are exist on Ivybridge or later products. RDSEED are Broadwell or later products.. I should point out "Intel® AES New Instructions" is will cover RDSEED and RDRAND. – Ramhound – 2015-11-12T12:01:45.417

@Ramhound - My bad... The MacBook Pro is an i7 (not i5). But I can't find the processor specs. Apple does not appear to provide them, even on their Tech Spec page (its loaded with the MBP serial number). About all I can tell you is its the upgraded processor (2.4 GHz). The kid at the Apple store also told me it did have AES-NI and RDRAND, but that was a lie; it only had AES-NI. Lessons learned (for me): don't trust Apple, and don't let them ship you a device. Buy at the store, make them open it and inspect it on-site.

– jww – 2015-11-12T12:36:49.503

A 2011 Macbook won't have neither. You would have to look at products released with Ivybridge which would be after 2014. Broadwell would be products released in 2015. I can't believe there isn't a tool, that exists on OS X, to identify what CPU you have "Intel HD Graphics 3000" which means you have a Sandybridge product. – Ramhound – 2015-11-12T12:45:08.477

@Ramhound - thanks. "A 2011 Macbook won't have neither. .." - yes agreed. I actually deferred the MBP purchase until mid-2012 to ensure it would have both AES-NI and RDRAND. Like I said, purchase it at the store, don't let them ship you something, and open it for inspection at the store. And to add insult to injury, Apple abandoned the OS, so I can't take the MacBook with me in public because of CVE-2015-1130.

– jww – 2015-11-12T13:45:34.267

So why did you link to a 2011 product? – Ramhound – 2015-11-12T13:54:36.090

@Ramhound - "So why did you link to a 2011 product..." - As an example of data sheets stating AVX instruction set architectures over time. The best I can tell just about everything now a days is AVX, but not all AVX has the support (q.v.). – jww – 2015-11-12T13:56:00.100

Both 2011 and 2012 would be 2 and 3 years before any Ivybridge product was even released. So neither has the require instruction extensions. So as I point out, the product never could support it, which is always best to get impartial confirmation before a purchase. Even with a 2012 product, you should have no trouble, installing El Capitan on it.

– Ramhound – 2015-11-12T14:04:03.603

It might help pointing out that these instructions are not in the Advanced Vector Extensions (AVX) to begin with. They are indicated by Intel simply by an indication the product supports Intel® AES New Instructions on Intel's ark website. As pointed out the support for one instruction does not mean support for the other. – Ramhound – 2015-11-12T14:07:31.850

My dates are all screwed up. Ivybridge would have been a 2012 product. which means strictly speaking it should support RDRAND. If you are wondering if your specific laptop supports it, I will ask again, for the CPU you have. – Ramhound – 2015-11-12T14:11:44.997

"...these instructions are not in the Advanced Vector Extensions..." - Ah, OK. I could not find that information on Intel's site. Its probably there, I just could not find it. "My dates are all screwed up..." - No big deal. Its going back a few years, and its understandable. I don't follow hardware like I used to, so this is one big fog to me. – jww – 2015-11-12T14:31:54.337

Answers

5

RDRAND and RDSEED are not a part of any specific ISA extension set. They are their own set and have their own specific bits allocated in the CPUID instruction.

They were developed under the "Bull Mountain" codename and are today marketed as Intel Secure Key.

Intel Secure Key was added in Broadwell, so you need that or any later generation. Broadwell generation means Intel Core i5 or i7 where the 4-digit number appended to it starts with a "5". Like an Core i7-5775C. Intel later released the Skylake generation, that also includes these instructions. Skylake has codes starting with a "6", like Core i7-6700.

AMD has added RDRAND and RDSEED in Carizzo.

Vojtech

Posted 2015-11-12T11:41:57.880

Reputation: 934

1You forgot to mention that RDRAND is supported by Ivybridge products. – Ramhound – 2015-11-12T12:46:20.930

3That's correct. RDRAND is in IvyBridge and Haswell in addition to Broadwell and Skylake. However IvyBridge and Haswell lack RDSEED. – Vojtech – 2015-11-12T13:19:43.720

Thanks Vojtech. it took three tries, but I finally got my hands on a 6th Gen i7. – jww – 2015-11-29T02:13:46.113

Asked: 2015-11-12T11:41:57.880

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