[Beignet] [PATCH 1/2] Handle edge and illegal values.

[Zhigang Gong]

On Thu, Aug 08, 2013 at 06:46:52PM +0800, Yi Sun wrote:
> Such as |x| = 1.0, |x| < 2**-27 and |x| > 1.
> 
> Signed-off-by: Yi Sun <yi.sun at intel.com>
> ---
>  backend/src/ocl_stdlib.tmpl.h |   35 +++++++++++++++++++++++++++++++++++
>  1 files changed, 35 insertions(+), 0 deletions(-)
> 
> diff --git a/backend/src/ocl_stdlib.tmpl.h b/backend/src/ocl_stdlib.tmpl.h
> index 84f15ca..899a085 100644
> --- a/backend/src/ocl_stdlib.tmpl.h
> +++ b/backend/src/ocl_stdlib.tmpl.h
> @@ -561,7 +561,42 @@ INLINE_OVERLOADABLE float __gen_ocl_internal_tanh(float x) {
>    float y = native_exp(-2 * x);
>    return (1 - y) / (1 + y);
>  }
> +
> +typedef union
> +{
> +  float value;
> +  int word;
> +} ieee_float_shape_type;
> +
> +#ifndef GET_FLOAT_WORD
> +# define GET_FLOAT_WORD(i,d)        \
> +do {                                \
> +  ieee_float_shape_type gf_u;       \
> +  gf_u.value = (d);                 \
> +  (i) = gf_u.word;                  \
> +} while (0)
> +#endif
> +
> +const float
You may need to use constant, rather than const, it will trigger compilation
error in my environment.
> +one =  1.0000000000e+00, /* 0x3F800000 */
> +huge =  1.000e+30,
> +pio2_hi = 1.57079637050628662109375f,
> +pio2_lo = -4.37113900018624283e-8f;

As ocl_stdlib.tmpl.h is a standard header file for all ocl kernels,
these four global constant values are visible to all ocl kernels.
Considering the names are very simple, I think this may be not a
good thing. You may need to change them to some thing like the
names defined in OpenCL spec:
M_PI_F
M_PI_2_F

For the other part of this patchset, LGTM. Thanks.

> +
>  INLINE_OVERLOADABLE float __gen_ocl_internal_asin(float x) {
> +  int hx, ix;
> +  GET_FLOAT_WORD(hx,x);
> +  ix = hx&0x7fffffff;
> +  if(ix == 0x3f800000) {
> +    return x*pio2_hi + x*pio2_lo;  /* asin(1)=+-pi/2 with inexact */
> +  }
> +  if(ix > 0x3f800000) {            /* |x|>= 1 */
> +    return (x-x) / (x-x);          /* asin(|x|>1) is NaN */
> +  }
> +  if(ix < 0x32000000) {            /* if |x| < 2**-27 */
> +    if(huge + x > one) return x;   /* return x with inexact if x!=0*/
> +  }
> +  /* 1 > |x| >= 2**-27 */
>    float sum = x, c = x, m = 1.0;
>    int n = 1;
>    do
> -- 
> 1.7.6.4
> 
> _______________________________________________
> Beignet mailing list
> Beignet at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/beignet