[PATCH 7/7] RISC-V: add zbb support to string functions

[Christoph Müllner]

On Fri, Nov 25, 2022 at 6:11 PM Conor Dooley <conor at kernel.org> wrote:
>
> On Fri, Nov 25, 2022 at 06:02:12PM +0100, Christoph Müllner wrote:
> > On Fri, Nov 25, 2022 at 5:39 PM Conor Dooley <conor at kernel.org> wrote:
> > >
> > > On Fri, Nov 25, 2022 at 05:35:39PM +0100, Christoph Müllner wrote:
> > > > On Fri, Nov 25, 2022 at 4:28 PM Andrew Jones <ajones at ventanamicro.com> wrote:
> > >
> > > > > /*
> > > > >  * Each sub-list is sorted alphabetically.
> > > > >  */
> > > > > #define S_EXTENSIONS                                                    \
> > > > >         __RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),         \
> > > > >         __RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC),                 \
> > > > >         __RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL),           \
> > > > >         __RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT),
> > > > >
> > > > > #define Zi_EXTENSIONS                                                   \
> > > > >         __RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),             \
> > > > >         __RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
> > > > >
> > > > > #define Zb_EXTENSIONS                                                   \
> > > > >         __RISCV_ISA_EXT_DATA(zbb, RISCV_ISA_EXT_ZICBOM),                \
> > > > >
> > > > > static struct riscv_isa_ext_data isa_ext_arr[] = {
> > > > >         Zi_EXTENSIONS
> > > > >         Zb_EXTENSIONS
> > > > >         S_EXTENSIONS
> > > > >         __RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX),
> > > > > };
> > > >
> > > > It might be worth to look how Binutils are grouping them:
> > > >   https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=bfd/elfxx-riscv.c#l1261
> > > >
> > > > They also group extensions together but use the following groups:
> > > >
> > > > const struct riscv_supported_ext *riscv_all_supported_ext[] =
> > > > {
> > > >   riscv_supported_std_ext,
> > > >   riscv_supported_std_z_ext,
> > > >   riscv_supported_std_s_ext,
> > > >   riscv_supported_std_zxm_ext,
> > > >   riscv_supported_vendor_x_ext,
> > > >   NULL
> > > > };
> > >
> > > I think in this case, Drew's differentiation between Zi & Zb is an
> > > improvement :)
> >
> >
> > That might be the case, but it also brings up the following questions:
> > Where to put Zf* extensions (between Zi and Zb)?
>
> I don't think that differs either way?
>
> > Where to put Zk* and Zv* (after Zb*)?
>
> Ditto?
>
> > Adding a subgroup for each Z{N}* extension might result in many small
> > groups with little benefit.
>
> If it prevents another one of these ordering episodes, I think it's
> worth doing! If a "group" only has one element it could alternatively be
> added directly also.

Sounds good then.

>
> Also neat, you got your mailer sorted :)

One just needs to remember to check the "Plain text mode" box.