Re: [musl] [PATCH] Fix build error for vabs.f64 and vsqrt.f64

[Szabolcs Nagy <nsz@port70.net>]

* Jinliang Li <jinliang.li@linux.alibaba.com> [2020-11-20 18:45:03 +0800]:
> To fix the build error "Error: selected fpu does not support instruction vabs.f64 or vsqrt.f64",
> when single precision fpu, e.g. -mfpu=fpv5-sp-d16 is selected.
> 
> Check if double precision fpu is supported for vabs.f64 and vsqrt.f64.

yes i think this patch should work:

both vfp and softfp call abi should work with single prec fpu.

the fp register state and load/store instructions should be
compatible between double prec and single prec only fpu so
setjmp/longjmp/fenv asm should work too.

so it is enough to fix up math asm to support single prec only fpu.

> ---
>  src/math/arm/fabs.c | 2 +-
>  src/math/arm/sqrt.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/src/math/arm/fabs.c b/src/math/arm/fabs.c
> index f890520a..6e1d367d 100644
> --- a/src/math/arm/fabs.c
> +++ b/src/math/arm/fabs.c
> @@ -1,6 +1,6 @@
>  #include <math.h>
>  
> -#if __ARM_PCS_VFP
> +#if __ARM_PCS_VFP && __ARM_FP&8
>  
>  double fabs(double x)
>  {
> diff --git a/src/math/arm/sqrt.c b/src/math/arm/sqrt.c
> index 874af960..567e2e91 100644
> --- a/src/math/arm/sqrt.c
> +++ b/src/math/arm/sqrt.c
> @@ -1,6 +1,6 @@
>  #include <math.h>
>  
> -#if __ARM_PCS_VFP || (__VFP_FP__ && !__SOFTFP__)
> +#if (__ARM_PCS_VFP || (__VFP_FP__ && !__SOFTFP__)) && (__ARM_FP&8)
>  
>  double sqrt(double x)
>  {
> -- 
> 2.28.0