[PATCH] LoongArch: Use "$fcsr0" instead of "$r0" in _FPU_{GET,SET}CW

[Adhemerval Zanella Netto]

On 29/04/24 04:31, Xi Ruoyao wrote:
> Clang inline-asm parser does not allow using "$r0" in
> movfcsr2gr/movgr2fcsr, so everything using _FPU_{GET,SET}CW is now
> failing to build with Clang on LoongArch.  As we now requires Binutils
>> = 2.41 which supports using "$fcsr0" here, use it instead of "$r0" to
> fix the issue.
> 
> Link: https://github.com/loongson-community/discussions/issues/53#issuecomment-2081507390
> Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=4142b2368353
> Signed-off-by: Xi Ruoyao <xry111@xry111.site>

LGTM, thanks.  It is safe to use with old gcc and binutils or the new 
constraint required a specific gcc version?

> ---
> 
> People in the Cc list will receive this twice because I've mistyped the
> address of libc-alpha first time.  Sorry.  Stupid I :(.
> 
>  sysdeps/loongarch/fpu_control.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/sysdeps/loongarch/fpu_control.h b/sysdeps/loongarch/fpu_control.h
> index 54add4e01c..3cdf2417d9 100644
> --- a/sysdeps/loongarch/fpu_control.h
> +++ b/sysdeps/loongarch/fpu_control.h
> @@ -91,8 +91,8 @@ typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__SI__)));
>  /* Macros for accessing the hardware control word.  */
>  extern fpu_control_t __loongarch_fpu_getcw (void) __THROW;
>  extern void __loongarch_fpu_setcw (fpu_control_t) __THROW;
> -#define _FPU_GETCW(cw) __asm__ volatile ("movfcsr2gr %0,$r0" : "=r"(cw))
> -#define _FPU_SETCW(cw) __asm__ volatile ("movgr2fcsr $r0,%0" : : "r"(cw))
> +#define _FPU_GETCW(cw) __asm__ volatile ("movfcsr2gr %0,$fcsr0" : "=r"(cw))
> +#define _FPU_SETCW(cw) __asm__ volatile ("movgr2fcsr $fcsr0,%0" : : "r"(cw))
>  
>  /* Default control word set at startup.  */
>  extern fpu_control_t __fpu_control;