SSE instructions

[Simon Glass]

Hi Bin,

On Thu, 28 Sept 2023 at 08:15, Bin Meng <bmeng.cn at gmail.com> wrote:
>
> Hi Simon,
>
> On Thu, Sep 28, 2023 at 10:41 AM Simon Glass <sjg at chromium.org> wrote:
> >
> > Hi Bin,
> >
> > U-Boot 64-bit on x86 disables sse, but when enabling Truetype I get a
> > compiler error:
> >
> > drivers/video/console_truetype.c: In function 'frac':
> > drivers/video/console_truetype.c:30:15: error: SSE register return
> > with SSE disabled
> > 30 | static double frac(double val)
> >
> > Do you know how to enable SSE for 64-bit?
> >
>
> The following patch could enable SSE for 64-bit:
>
> diff --git a/arch/x86/config.mk b/arch/x86/config.mk
> index 26ec1af2f0..250d7c9948 100644
> --- a/arch/x86/config.mk
> +++ b/arch/x86/config.mk
> @@ -27,7 +27,7 @@ ifeq ($(IS_32BIT),y)
>  PLATFORM_CPPFLAGS += -march=i386 -m32
>  else
>  PLATFORM_CPPFLAGS += $(if $(CONFIG_SPL_BUILD),,-fpic) -fno-common
> -march=core2 -m64
> -PLATFORM_CPPFLAGS += -mno-mmx -mno-sse
> +PLATFORM_CPPFLAGS += -mno-mmx
>  endif
>
> However as Heinrich mentioned, U-Boot codes should be written in a
> "floating point free" way.
>
> The fix should really be updating console_truetype.c to use integers
> instead of using float/double.

Yes, I can do that, but it hangs going into 64-bit mode, which is
presumably why the flag was added. In fact it was your commit!

Is there some missing init somewhere?

Regards,
Simon