Re: [PATCH] Fix absd emulation

[Ralf Baechle <ralf@linux-mips.org>]

On Fri, Jul 10, 2009 at 01:50:58AM -0700, Raghu Gandham wrote:

> From: Robin Randhawa <robin@mips.com>
> 
> Signed-off-by: Chris Dearman <chris@mips.com>
> ---
> 
>  arch/mips/math-emu/dp_simple.c |   11 ++++-------
>  arch/mips/math-emu/sp_simple.c |    3 ---
>  2 files changed, 4 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/mips/math-emu/dp_simple.c b/arch/mips/math-emu/dp_simple.c
> index 1c555e6..6ff4655 100644
> --- a/arch/mips/math-emu/dp_simple.c
> +++ b/arch/mips/math-emu/dp_simple.c
> @@ -76,15 +76,12 @@ ieee754dp ieee754dp_abs(ieee754dp x)
>  	CLEARCX;
>  	FLUSHXDP;
>  
> +	/* Clear sign ALWAYS, irrespective of NaN */
> +	DPSIGN(x) = 0;
> +
>  	if (xc == IEEE754_CLASS_SNAN) {
>  		SETCX(IEEE754_INVALID_OPERATION);
> -		return ieee754dp_nanxcpt(ieee754dp_indef(), "neg");
> +		return ieee754dp_nanxcpt(ieee754dp_indef(), "abs");
>  	}
> -
> -	if (ieee754dp_isnan(x))	/* but not infinity */
> -		return ieee754dp_nanxcpt(x, "abs", x);
> -
> -	/* quick fix up */
> -	DPSIGN(x) = 0;
>  	return x;
>  }

It seems that abs.s needs the same changes except the string constant.  Or
why was only abs.d changed?

(And what is the official behaviour anyway.  It seems I can spend another
quality night over IEEE 754 ...)

> diff --git a/arch/mips/math-emu/sp_simple.c b/arch/mips/math-emu/sp_simple.c
> index 770f0f4..cdec1a2 100644
> --- a/arch/mips/math-emu/sp_simple.c
> +++ b/arch/mips/math-emu/sp_simple.c
> @@ -61,9 +61,6 @@ ieee754sp ieee754sp_neg(ieee754sp x)
>  		SPSIGN(y) = SPSIGN(x);
>  		return ieee754sp_nanxcpt(y, "neg");
>  	}
> -
> -	if (ieee754sp_isnan(x))	/* but not infinity */
> -		return ieee754sp_nanxcpt(x, "neg", x);
>  	return x;
>  }

The subject of the patch was claiming a fix to abs.d but this is fiddling
with neg.s.  And why not the equivalent change to neg.d?

  Ralf