Re: [PATCH 07/13] target/hexagon: add v68 HVX IEEE float conversion insns

[Taylor Simpson <ltaylorsimpson@gmail.com>]

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On Mon, Mar 23, 2026 at 7:16 AM Matheus Tavares Bernardino <
matheus.bernardino@oss.qualcomm.com> wrote:

> Add HVX IEEE floating-point conversion instructions:
> - vconv_hf_h, vconv_h_hf, vconv_sf_w, vconv_w_sf: vconv operations
> - vcvt_hf_sf, vcvt_sf_hf: float <-> half float conversions
> - vcvt_hf_b, vcvt_hf_h, vcvt_hf_ub, vcvt_hf_uh: int to half float
> - vcvt_b_hf, vcvt_h_hf, vcvt_ub_hf, vcvt_uh_hf: half float to int
>
> Signed-off-by: Matheus Tavares Bernardino <
> matheus.bernardino@oss.qualcomm.com>
> ---
>  target/hexagon/mmvec/kvx_ieee.h              | 21 +++++
>  target/hexagon/mmvec/kvx_ieee.c              | 98 ++++++++++++++++++++
>  target/hexagon/imported/mmvec/encode_ext.def | 18 ++++
>  target/hexagon/imported/mmvec/ext.idef       | 97 +++++++++++++++++++
>  4 files changed, 234 insertions(+)
>
> diff --git a/target/hexagon/mmvec/kvx_ieee.c
> b/target/hexagon/mmvec/kvx_ieee.c
> index 33621a15f3..bbeec09707 100644
> --- a/target/hexagon/mmvec/kvx_ieee.c
> +++ b/target/hexagon/mmvec/kvx_ieee.c
> @@ -131,3 +131,101 @@ uint16_t qf_min_hf(uint16_t a1, uint16_t a2,
> float_status *fp_status)
>      if (float16_is_pos_nan(f2) || float16_is_neg_nan(f1)) return a1;
>      return fp_min_hf(a1, a2, fp_status);
>  }
> +
> +uint16_t f32_to_f16(uint32_t a, float_status *fp_status)
> +{
> +    return float16_val(float32_to_float16(make_float32(a), true,
> fp_status));
> +}
> +
> +uint32_t f16_to_f32(uint16_t a, float_status *fp_status)
> +{
> +    return float32_val(float16_to_float32(make_float16(a), true,
> fp_status));
> +}
> +
> +uint16_t f16_to_uh(uint16_t op1, float_status *fp_status)
> +{
> +    return float16_to_uint16_scalbn(make_float16(op1),
> +                                    float_round_nearest_even,
>

Does HVX always use this rounding mode?  The scalar core uses the rounding
mode in USR.

There are several more instances below.


> +                                    0, fp_status);
> +}
> +
> +int16_t f16_to_h(uint16_t op1, float_status *fp_status)
> +{
> +    return float16_to_int16_scalbn(make_float16(op1),
> +                                   float_round_nearest_even,

+                                   0, fp_status);
> +}
> +
> +uint8_t f16_to_ub(uint16_t op1, float_status *fp_status)
> +{
> +    return float16_to_uint8_scalbn(make_float16(op1),
> +                                   float_round_nearest_even,

+                                   0, fp_status);
> +}
> +
> +int8_t f16_to_b(uint16_t op1, float_status *fp_status)
> +{
> +    return float16_to_int8_scalbn(make_float16(op1),
> +                                   float_round_nearest_even,

+                                   0, fp_status);
> +}
> +
> +uint16_t uh_to_f16(uint16_t op1)
> +{
> +    return uint64_to_float16_scalbn(op1, float_round_nearest_even, 0);
> +}
> +
> +uint16_t h_to_f16(int16_t op1)
> +{
> +    return int64_to_float16_scalbn(op1, float_round_nearest_even, 0);
> +}
> +
> +uint16_t ub_to_f16(uint8_t op1)
> +{
> +    return uint64_to_float16_scalbn(op1, float_round_nearest_even, 0);
> +}
> +
> +uint16_t b_to_f16(int8_t op1)
> +{
> +    return int64_to_float16_scalbn(op1, float_round_nearest_even, 0);
> +}
> +
> +int32_t conv_sf_w(int32_t a, float_status *fp_status)
> +{
> +    return float32_val(int32_to_float32(a, fp_status));
> +}
> +
> +int16_t conv_hf_h(int16_t a, float_status *fp_status)
> +{
> +    return float16_val(int16_to_float16(a, fp_status));
> +}
> +
> +int32_t conv_w_sf(uint32_t a, float_status *fp_status)
> +{
> +    float_status scratch_fpst = {};
> +    const float32 W_MAX = int32_to_float32(INT32_MAX, &scratch_fpst);
> +    const float32 W_MIN = int32_to_float32(INT32_MIN, &scratch_fpst);
> +    float32 f1 = make_float32(a);
> +
> +    if (float32_is_any_nan(f1) || float32_is_infinity(f1) ||
> +        float32_le_quiet(W_MAX, f1, fp_status) ||
> +        float32_le_quiet(f1, W_MIN, fp_status)) {
> +        return float32_is_neg(f1) ? INT32_MIN : INT32_MAX;
> +    }
>

Does float32_to_int32 handle these checks?


> +    return float32_to_int32_round_to_zero(f1, fp_status);
>

Rounding mode?


> +}
> +
> +int16_t conv_h_hf(uint16_t a, float_status *fp_status)
> +{/
> +    float_status scratch_fpst = {};
> +    const float16 H_MAX = int16_to_float16(INT16_MAX, &scratch_fpst);
> +    const float16 H_MIN = int16_to_float16(INT16_MIN, &scratch_fpst);
> +    float16 f1 = make_float16(a);
> +
> +    if (float16_is_any_nan(f1) || float16_is_infinity(f1) ||
> +        float16_le_quiet(H_MAX, f1, fp_status) ||
> +        float16_le_quiet(f1, H_MIN, fp_status)) {
> +        return float16_is_neg(f1) ? INT16_MIN : INT16_MAX;
> +    }
> +    return float16_to_int16_round_to_zero(f1, fp_status);
> +}
>

Ditto

Thanks,
Taylor

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