Re: [Qemu-devel] [PATCH 1/2] softfloat: Enable run-time-configurable meaning of signaling NaN bit

[Richard Henderson]

On 03/25/2016 05:50 AM, Aleksandar Markovic wrote:
> +float16 float16_default_nan(float_status *status) {

{ on the next line.

> +        return const_float64(LIT64( 0xFFF8000000000000 ));

Let's please fix the horrible formatting in this file as we touch the lines, 
please.

> -#define floatx80_default_nan_high 0x7FFF
> -#define floatx80_default_nan_low  LIT64(0xBFFFFFFFFFFFFFFF)
> -#else
> -#define floatx80_default_nan_high 0xFFFF
> -#define floatx80_default_nan_low  LIT64( 0xC000000000000000 )
> -#endif
> +uint16_t floatx80_default_nan_high(float_status *status) {
> +uint64_t floatx80_default_nan_low(float_status *status) {

Why do you need two separate functions for this?

> +floatx80 floatx80_default_nan(float_status *status) {

Seems to me this one is good enough, and indeed preferable.

> -#define float128_default_nan_high LIT64(0x7FFF7FFFFFFFFFFF)
> -#define float128_default_nan_low  LIT64(0xFFFFFFFFFFFFFFFF)
...
> +float128 float128_default_nan(float_status *status) {

Likewise.


> diff --git a/target-alpha/cpu.c b/target-alpha/cpu.c
> index 2eab060..1714387 100644
> --- a/target-alpha/cpu.c
> +++ b/target-alpha/cpu.c
> @@ -277,6 +277,8 @@ static void alpha_cpu_initfn(Object *obj)
>   #endif
>       env->lock_addr = -1;
>       env->fen = 1;
> +
> +    set_snan_bit_is_one(0, &env->fp_status);

We've just done a memset of (most of) the entire cpu struct.  We don't need to 
re-initialize this field to zero here.  Same with most of the other cpus.


r~