Re: [PATCH] dt-bindings: riscv: cpus: Add AMD MicroBlaze V compatible

[Keryell, Ronan (XILINX LABS)]

On 11/8/23 09:12, Rob Herring wrote:

> On Mon, Nov 06, 2023 at 12:37:47PM +0100, Michal Simek wrote:
>> MicroBlaze V is new AMD/Xilinx soft-core 32bit RISC-V processor IP.
>> It is hardware compatible with classic MicroBlaze processor.
> 
> How is that possible? It's a different instruction set, right? I suppose
> the IP interfaces (signals) are the same/compatible.

Coincidentally, I asked myself the same question, so I asked my former 
manager who designed the ancestor of this processor. The answer is

| It is still the same MicroBlaze pipeline just with a different
| instruction decoder up front. The “macro ops” are now RISC V
| instructions, the “micro-ops” are still the same operations in the
| various MicroBlaze pipeline stages.

So, yes, all the hardware interface is the same.
-- 
Ronan KERYELL, Research Labs / San José, California.
AMD Research and Advanced Development.