Hi, Richard and Xuerui,
On Mon, Aug 15, 2022 at 4:54 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
On 8/14/22 09:55, WANG Xuerui wrote:
From: WANG Xuerui <git@xen0n.name>
The only LoongArch CPU implemented is modeled after the Loongson
3A5000,
but it is not the real thing, ...
The 3A5000 is the SoC, as far as I could find, and the documentation
of that says the core
is named the la464.
In general, high-fidelity models can and should be named after the
real
hardware model, while generic emulation-oriented models should be
named
after ISA levels.
This wasn't intended to be a generic emulation model, as far as I
know. There are missing
features, but presumably those would eventually be filled in.
For now, the best reference for LoongArch ISA levels
is the revision number of the LoongArch ISA Manual, of which v1.00 is
still the latest. (v1.01 and v1.02 are minor revisions without
substantive change.)
As defined by various specs, the vendor and model names are also
reflected in respective CSRs, and are 8 bytes long. So, rename "la464"
to "qemu64-v1.00", with "QEMU64" as vendor name and "v1.00" as model
name.
Eh, I suppose. I'm not really keen on this though, as I would
presume there will be
eventual forward progress on completing the real cpu model. We
simply won't give any
compatibility guarantees for loongarch until we are ready to do so.
In my opinion, real cpu name (Loongson-3A5000, Loongson-3A6000, etc.)
and generic qemu emulated name (qemu64-v1.00, qemu64-v2.00, vx.xx is
the ISA level, I found this style is used for x86) are both
acceptable. But la464 is not a good cpu name, because la264 and la464
are in the same ISA level, while la664 will be in a new level.