Re: [Buildroot] [PATCH 1/4] ARC: Add support for generic HS48 processor

Yann E. MORIN
2021-01-16T15:35:46Z

Vineet, All,

On 2021-01-15 12:03 -0800, Vineet Gupta spake thusly:
> For the HS48 processor, BR currently builds with -mcpu=hs4x_rel31 which
> generates suboptimal code as it inhibits delay slot and back-back ST and so on.
>
> Enable a new variant to build with -mcpu=hs4x for normal codegen.
>
> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
> ---
> arch/Config.in.arc | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/arch/Config.in.arc b/arch/Config.in.arc
> index fdfafda31c72..259d6f3ab8b9 100644
> --- a/arch/Config.in.arc
> +++ b/arch/Config.in.arc
> @@ -39,9 +39,14 @@ config BR2_archs38_full
>
> config BR2_archs4x_rel31
> bool "ARC HS48 rel 31"
> + help
> + Build for HS48 release 3.1
> +
> +config BR2_archs4x
> + bool "ARC HS48"
> help
> Latest release of HS48 processor
> - - Dual- and quad multiply and MC oprations
> + - Dual and Quad multiply and MAC operations
> - Double-precision FPU
>
> endchoice
> @@ -49,7 +54,7 @@ endchoice
> # Choice of atomic instructions presence
> config BR2_ARC_ATOMIC_EXT
> bool "Atomic extension (LLOCK/SCOND instructions)"
> - default y if BR2_arc770d || BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31
> + default y if BR2_arc770d || BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31 || BR2_archs4x

Those started to be rather long lines, so I split them.

> config BR2_ARCH
> default "arc" if BR2_arcle
> @@ -70,10 +75,11 @@ config BR2_GCC_TARGET_CPU
> default "hs38" if BR2_archs38_64mpy
> default "hs38_linux" if BR2_archs38_full
> default "hs4x_rel31" if BR2_archs4x_rel31
> + default "hs4x" if BR2_archs4x
>
> config BR2_READELF_ARCH_NAME
> default "ARCompact" if BR2_arc750d || BR2_arc770d
> - default "ARCv2" if BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31
> + default "ARCv2" if BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31 || BR2_archs4x

Ditto.

> choice
> prompt "MMU Page Size"
> @@ -93,7 +99,7 @@ choice
>
> config BR2_ARC_PAGE_SIZE_4K
> bool "4KB"
> - depends on BR2_arc770d || BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31
> + depends on BR2_arc770d || BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31 || BR2_archs4x

In fact, the only variant that does not have 4K pages is 750d, so I
inverted the logic to:

depends on !BR2_arc750d

So the lines are not too long anymore.

If the situation becones more complex than that, then we could introduce
intermediate symbols, like;

config BR2_ARC_HAS_4K_PAGES
bool

which could then be selected by the variants that do have it, e.g.:

config BR2_archs4x
bool "ARC HS48"
select BR2_ARC_HAS_4K_PAGES

and then the 4K choice would depend on it;

config BR2_ARC_PAGE_SIZE_4K
bool "4KB"
depends on BR2_ARC_HAS_4K_PAGES

I was about to do that, but if 750d is definitely the only variant to
not support those 4K or 16K pages, this would be overkill...

> config BR2_ARC_PAGE_SIZE_8K
> bool "8KB"
> @@ -103,7 +109,7 @@ config BR2_ARC_PAGE_SIZE_8K
>
> config BR2_ARC_PAGE_SIZE_16K
> bool "16KB"
> - depends on BR2_arc770d || BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31
> + depends on BR2_arc770d || BR2_archs38 || BR2_archs38_64mpy || BR2_archs38_full || BR2_archs4x_rel31 || BR2_archs4x

Ditto.

Regards,
Yann E. MORIN.

> endchoice
>
> --
> 2.25.1
>
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> buildroot mailing list
> buildroot@busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

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