[U-Boot] [PATCH v2] riscv: add Kconfig entries for the F and D ISA extensions support

[Eric Lin]

Hi Bin
>
> Hi Eric,
>
> On Tue, Jun 4, 2019 at 1:51 PM Eric Lin <tesheng at andestech.com> wrote:
> >
> > This patch adds Kconfig entries for the F (Single-Precision)
> > and D (Double-Precision) floating point instruction-set extensions.
> >
> > Signed-off-by: Eric Lin <tesheng at andestech.com>
> > ---
> > Changes for v2:
> >         - Grammatical correction in commit message "adds"
> >         - Fixed the config name to indicate both F and D
> >
> >  arch/riscv/Kconfig  |  7 +++++++
> >  arch/riscv/Makefile | 12 ++++++++----
> >  2 files changed, 15 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > index 362f3cdc65..e7a76c67cc 100644
> > --- a/arch/riscv/Kconfig
> > +++ b/arch/riscv/Kconfig
> > @@ -91,6 +91,13 @@ config RISCV_ISA_C
> >           when building U-Boot, which results in compressed instructions in the
> >           U-Boot binary.
> >
> > +config RISCV_ISA_FD
>
> Again like I said in the v1 patch, I am not in favor of adding such to
> U-Boot, but if we have to add such, I think we need add finer control
> of single-precision and double-precision via 2 options, one for ISA_F
> and one for ISA_D. It's possible that toolchain only supports ISA_F,
> although I should say that's a bit weird.
>

OK, I see. I'll modify the patch as below:

 +config RISCV_ISA_F
+       bool "Emit single-precision floating-point instructions"
+       help
+         Adds "F" to the ISA subsets that the toolchain is allowed to emit
+         when building U-Boot, which results in single-precision instructions
+         in the U-Boot binary.
+
+config RISCV_ISA_D
+       bool "Emit double-precision floating-point instructions"
+       help
+         Adds "D" to the ISA subsets that the toolchain is allowed to emit
+         when building U-Boot, which results in double-precision instructions
+         in the U-Boot binary.

 ifeq ($(CONFIG_RISCV_ISA_A),y)
        ARCH_A = a
 endif
+ifeq ($(CONFIG_RISCV_ISA_F),y)
+       ARCH_F = f
+       ABI := $(ABI)f
+endif
+ifeq ($(CONFIG_RISCV_ISA_D),y)
+       ARCH_D = fd
+       ABI := $(ABI)d
+endif
 ifeq ($(CONFIG_RISCV_ISA_C),y)
        ARCH_C = c
 endif

-ARCH_FLAGS = -march=$(ARCH_BASE)$(ARCH_A)$(ARCH_C) -mabi=$(ABI) \
-            -mcmodel=$(CMODEL)
+ARCH_FLAGS = -march=$(ARCH_BASE)$(ARCH_A)$(ARCH_F)$(ARCH_D)$(ARCH_C)
-mabi=$(ABI) \
+                                -mcmodel=$(CMODEL)

The ISA_D -march will imply fd

> > +       bool "Emit Floating-point instructions"
> > +       help
> > +         Adds "F" and "D" to the ISA subsets that the toolchain is allowed to emit
> > +         when building U-Boot, which results in Single and Double-precision instructions
> > +         in the U-Boot binary.
> > +
> >  config RISCV_ISA_A
> >         def_bool y
> >
> > diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
> > index 0b80eb8d86..5a5c8e75f0 100644
> > --- a/arch/riscv/Makefile
> > +++ b/arch/riscv/Makefile
> > @@ -5,15 +5,19 @@
> >
> >  ifeq ($(CONFIG_ARCH_RV64I),y)
> >         ARCH_BASE = rv64im
> > -       ABI = lp64
> > +       ABI := lp64
> >  endif
> >  ifeq ($(CONFIG_ARCH_RV32I),y)
> >         ARCH_BASE = rv32im
> > -       ABI = ilp32
> > +       ABI := ilp32
> >  endif
> >  ifeq ($(CONFIG_RISCV_ISA_A),y)
> >         ARCH_A = a
> >  endif
> > +ifeq ($(CONFIG_RISCV_ISA_FD),y)
> > +       ARCH_FD = fd
> > +       ABI := $(ABI)d
> > +endif
> >  ifeq ($(CONFIG_RISCV_ISA_C),y)
> >         ARCH_C = c
> >  endif
> > @@ -24,8 +28,8 @@ ifeq ($(CONFIG_CMODEL_MEDANY),y)
> >         CMODEL = medany
> >  endif
> >
> > -ARCH_FLAGS = -march=$(ARCH_BASE)$(ARCH_A)$(ARCH_C) -mabi=$(ABI) \
> > -            -mcmodel=$(CMODEL)
> > +ARCH_FLAGS = -march=$(ARCH_BASE)$(ARCH_A)$(ARCH_FD)$(ARCH_C) -mabi=$(ABI) \
> > +                                -mcmodel=$(CMODEL)
> >
> >  PLATFORM_CPPFLAGS      += $(ARCH_FLAGS)
> >  CFLAGS_EFI             += $(ARCH_FLAGS)
> > --
>
> Regards,
> Bin

Thanks for your review

Regards,
Eric