Re: [Qemu-devel] [PATCH 10/18] target-riscv: Add Single Precision Floating-Point Instructions

[Richard Henderson]

On 09/26/2016 03:56 AM, Sagar Karandikar wrote:
> +uint64_t helper_fsgnj_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +{
> +    frs1 = (frs1 & ~(uint32_t)INT32_MIN) | (frs2 & (uint32_t)INT32_MIN);
> +    return frs1;
> +}
> +
> +uint64_t helper_fsgnjn_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +{
> +    frs1 = (frs1 & ~(uint32_t)INT32_MIN) | ((~frs2) & (uint32_t)INT32_MIN);
> +    return frs1;
> +}
> +
> +uint64_t helper_fsgnjx_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +{
> +    frs1 = frs1 ^ (frs2 & (uint32_t)INT32_MIN);
> +    return frs1;
> +}

These are simple enough to implement inline.

> +
> +uint64_t helper_fmin_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +{
> +    frs1 = float32_is_any_nan(frs2) ||
> +           float32_lt_quiet(frs1, frs2, &env->fp_status) ? frs1 : frs2;
> +    set_fp_exceptions();
> +    return frs1;
> +}

float32_minnum.

> +
> +uint64_t helper_fmax_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +{
> +    frs1 = float32_is_any_nan(frs2) ||
> +           float32_le_quiet(frs2, frs1, &env->fp_status) ? frs1 : frs2;
> +    set_fp_exceptions();
> +    return frs1;
> +}

float32_maxnum.

> +target_ulong helper_fcvt_w_s(CPURISCVState *env, uint64_t frs1, uint64_t rm)
> +{
> +    set_float_rounding_mode(RM, &env->fp_status);
> +    frs1 = (int64_t)((int32_t)float32_to_int32(frs1, &env->fp_status));

You do not need either of these casts.

> +target_ulong helper_fcvt_wu_s(CPURISCVState *env, uint64_t frs1, uint64_t rm)
> +{
> +    set_float_rounding_mode(RM, &env->fp_status);
> +    frs1 = (int64_t)((int32_t)float32_to_uint32(frs1, &env->fp_status));

You do not need the cast to int64_t.  Also, remove the extra parenthesis.

> +union ui32_f32 { uint32_t ui; uint32_t f; };

What's the point of this?

> +
> +uint_fast16_t float32_classify(uint32_t a, float_status *status)

No need for uint_fast16_t.  Just use uint32_t.

> +{
> +    union ui32_f32 uA;
> +    uint_fast32_t uiA;
> +
> +    uA.f = a;
> +    uiA = uA.ui;
> +
> +    uint_fast16_t infOrNaN = expF32UI(uiA) == 0xFF;

float32_is_infinity or float32_is_any_nan.

> +    uint_fast16_t subnormalOrZero = expF32UI(uiA) == 0;

float32_is_zero_or_denormal

> +    bool sign = signF32UI(uiA);

float32_is_neg.


r~