Re: [PATCH v6 1/4] bswap: Add the ability to store to an unaligned 24 bit field

[Philippe Mathieu-Daudé]

On 20/5/23 17:15, Richard Henderson wrote:
> On 5/20/23 06:15, BALATON Zoltan wrote:
> > On Sat, 20 May 2023, Peter Maydell wrote:
> > > On Fri, 19 May 2023 at 15:19, Jonathan Cameron via
> > > <qemu-devel@nongnu.org> wrote:
> > > > From: Ira Weiny <ira.weiny@intel.com>
> > > >
> > > > CXL has 24 bit unaligned fields which need to be stored to.  CXL is
> > > > specified as little endian.
> > > >
> > > > Define st24_le_p() and the supporting functions to store such a field
> > > > from a 32 bit host native value.
> > > >
> > > > The use of b, w, l, q as the size specifier is limiting.  So "24" was
> > > > used for the size part of the function name.
> >
> > Maybe it's clearer to use 24 but if we want to keep these somewhat 
> > consistent how about using t for Triplet, Three-bytes or Twenty-four?
>
> I think it's clearer to use '3'.
> When I added 128-bit support I used cpu_ld16_mmu.

There is also ld8u / ld8s / st8.

> I think it would be clearer to not use letters anywhere, and to use 
> units of bytes instead of units of bits (no one can store just a bit), 
> but changing everything is a big job.

So:

ldub ->  ld1u,

lduw_le -> ld2u_le,

virtio_stl -> virtio_st4,

stq_be -> st8_be.

Right?

Also we have:

cpu_ld/st_*
virtio_ld/st_*
ld/st_*_phys
ld/st_*_pci_dma
address_space_ld/st

While mass-changing, we could use FOO_ld/st_BAR with FOO
for API and BAR for API variant (endian, mmuidx, ra, ...):

So:

ld/st_*_pci_dma -> pci_dma_ld/st_*

for ld/st_*_phys I'm not sure.