Re: [Qemu-devel] [PATCH 2/4] softfloat: add float32_set_sign(), float32_infinity, float64_half, float64_256 and float64_512.

[Aurelien Jarno <aurelien@aurel32.net>]

On Fri, Feb 18, 2011 at 03:49:15PM +0100, Christophe Lyon wrote:
> These constants and utility function are needed to implement some
> helpers. Defining constants avoids the need to re-compute them at
> runtime.
> 
> Signed-off-by: Christophe Lyon <christophe.lyon@st.com>
> ---
>  fpu/softfloat.h |    9 +++++++++
>  1 files changed, 9 insertions(+), 0 deletions(-)
> 
> diff --git a/fpu/softfloat.h b/fpu/softfloat.h
> index f34a938..9bd4a50 100644
> --- a/fpu/softfloat.h
> +++ b/fpu/softfloat.h
> @@ -379,9 +379,15 @@ INLINE int float32_is_zero_or_denormal(float32 a)
>      return (float32_val(a) & 0x7f800000) == 0;
>  }
>  
> +INLINE float32 float32_set_sign(float32 a, int sign)
> +{
> +    return make_float32((float32_val(a) & 0x7fffffff) | (sign << 31));
> +}
> +
>  #define float32_zero make_float32(0)
>  #define float32_one make_float32(0x3f800000)
>  #define float32_ln2 make_float32(0x3f317218)
> +#define float32_infinity make_float32(0x7f800000)
>  
>  
>  /*----------------------------------------------------------------------------
> @@ -482,6 +488,9 @@ INLINE int float64_is_any_nan(float64 a)
>  #define float64_zero make_float64(0)
>  #define float64_one make_float64(0x3ff0000000000000LL)
>  #define float64_ln2 make_float64(0x3fe62e42fefa39efLL)
> +#define float64_half make_float64(0x3fe0000000000000LL)
> +#define float64_256 make_float64(0x4070000000000000LL)
> +#define float64_512 make_float64(0x4080000000000000LL)
>  
>  /*----------------------------------------------------------------------------
>  | The pattern for a default generated double-precision NaN.

While it's probably a good idea to define the commonly used values in
softfloat.h, I don't think we should have all the values used by the
different targets here. Infinity, one, half, two probably have their
place here, I don't think it's the case of 256 and 512. It should be
better to defined them at the target level. Also for consistency, I
think it's better to define these value for all float size, or at least
for all the common ones (32, 64, maybe 16).

-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net