Hi All
1) is there any affordable SBC that could provide EOR3/RAX1/XAR/BCAX instructions?
2) My understanding is it is available on Cortex A75. so which most affordable hardware can be leverage for testing?
thanks a lot
Checkout also Cortex-A55. A little googling will help.
hey, I though Cortex 55 would do it as it is ARM 8.2A while i can't find these in the doc https://developer.arm.com/documentation/epm128372/2-0/ ? I will test on a Odroid C4 (Cortex A55) in the next weeks but i fell it is unlikely it will do it according that doc right?
May we have an answer from ARM to question 1?. Cheapest options are preferred. Thanks
From the doc:
The Cortex-A55 core is a mid-range, low-power core that implements the Armv8-A architecture with support for the Armv8.1-A extension, the Armv8.2-A extension, the RAS extension, the Load acquire (LDAPR) instructions introduced in the Armv8.3-A extension, and the Dot Product instructions introduced in the Armv8.4-A extension.
i can read this in the introduction but what is your conclusion? my understanding is that the specific instructions in question 1 are not available in Cortex 55. did you now came to that evidence too?
So i am still asking to the ARM SME on which Cortex & SBC i could find the EOR3/RAX1/XAR/BCAX instructions?
If you cannot believe the docs, get a SBC with CA55, and try the opcode.
I don't know what to do with your answers. But for the thread I dig into the ARM extensions and realised that the instructions have been added to ARM 8.4 A.
It is specified that the ARM V8.x should only contain V8.x+1 extensions and must not contain V8.x+2[1]. In substance Cortex A55 and A75 are ARM 8.2. How ever, I can see also from the C55 leaflets and the doc mentioned up[2] that the C55 is having extensions from V8.4 which is a breaking rule from [1] "
"An Armv8.x-A processor can implement any features from the next .x extension. However, it cannot implement features from any .x extension after that."
Personally, I like upgrade or promotions +)
So, can an ARM SME help me on question 1. I would like to understand where I can test these instructions called FEAT_SHA3. Thanks a lot.
Just receive the C55 but i feel like it will fail.
[1] https://developer.arm.com/architectures/learn-the-architecture/understanding-the-armv8-x-extensions/single-page
[2] https://developer.arm.com/documentation/epm128372/2-0/
:-) It seems ARM does not follow its rules.According [1] and the CA55 manual, it is a full 8.2 implementation and is allowed to implement partially 8.3 ISA but _not_ 8.4.So according [1], if it includes 8.4 it must be a full 8.3 implementation.
But, I would not wait for an "official" ARM statement in the forum. At least, I never saw one in all the years.
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