Looks the same as what we do for the others.
Reviewed-by: Jason Ekstrand <ja...@jlekstrand.net>
On Tue, Dec 4, 2018 at 1:18 AM Iago Toral Quiroga <ito...@igalia.com> wrote:
> ---
> src/compiler/spirv/vtn_glsl450.c | 48 ++++++++++++++++++++++++++++++--
> 1 file changed, 46 insertions(+), 2 deletions(-)
>
> diff --git a/src/compiler/spirv/vtn_glsl450.c
> b/src/compiler/spirv/vtn_glsl450.c
> index 85851755aab..bb340c87416 100644
> --- a/src/compiler/spirv/vtn_glsl450.c
> +++ b/src/compiler/spirv/vtn_glsl450.c
> @@ -389,6 +389,45 @@ build_atan2(nir_builder *b, nir_ssa_def *y,
> nir_ssa_def *x)
> nir_fneg(b, arc), arc);
> }
>
> +static nir_ssa_def *
> +build_frexp16(nir_builder *b, nir_ssa_def *x, nir_ssa_def **exponent)
> +{
> + assert(x->bit_size == 16);
> +
> + nir_ssa_def *abs_x = nir_fabs(b, x);
> + nir_ssa_def *zero = nir_imm_floatN_t(b, 0, 16);
> +
> + /* Half-precision floating-point values are stored as
> + * 1 sign bit;
> + * 5 exponent bits;
> + * 10 mantissa bits.
> + *
> + * An exponent shift of 10 will shift the mantissa out, leaving only
> the
> + * exponent and sign bit (which itself may be zero, if the absolute
> value
> + * was taken before the bitcast and shift).
> + */
> + nir_ssa_def *exponent_shift = nir_imm_int(b, 10);
> + nir_ssa_def *exponent_bias = nir_imm_intN_t(b, -14, 16);
> +
> + nir_ssa_def *sign_mantissa_mask = nir_imm_intN_t(b, 0x83ffu, 16);
> +
> + /* Exponent of floating-point values in the range [0.5, 1.0). */
> + nir_ssa_def *exponent_value = nir_imm_intN_t(b, 0x3800u, 16);
> +
> + nir_ssa_def *is_not_zero = nir_fne(b, abs_x, zero);
> +
> + /* Significand return must be of the same type as the input, but the
> + * exponent must be a 32-bit integer.
> + */
> + *exponent =
> + nir_i2i32(b,
> + nir_iadd(b, nir_ushr(b, abs_x, exponent_shift),
> + nir_bcsel(b, is_not_zero, exponent_bias,
> zero)));
> +
> + return nir_ior(b, nir_iand(b, x, sign_mantissa_mask),
> + nir_bcsel(b, is_not_zero, exponent_value, zero));
> +}
> +
> static nir_ssa_def *
> build_frexp32(nir_builder *b, nir_ssa_def *x, nir_ssa_def **exponent)
> {
> @@ -751,8 +790,10 @@ handle_glsl450_alu(struct vtn_builder *b, enum
> GLSLstd450 entrypoint,
> nir_ssa_def *exponent;
> if (src[0]->bit_size == 64)
> val->ssa->def = build_frexp64(nb, src[0], &exponent);
> - else
> + else if (src[0]->bit_size == 32)
> val->ssa->def = build_frexp32(nb, src[0], &exponent);
> + else
> + val->ssa->def = build_frexp16(nb, src[0], &exponent);
> nir_store_deref(nb, vtn_nir_deref(b, w[6]), exponent, 0xf);
> return;
> }
> @@ -762,9 +803,12 @@ handle_glsl450_alu(struct vtn_builder *b, enum
> GLSLstd450 entrypoint,
> if (src[0]->bit_size == 64)
> val->ssa->elems[0]->def = build_frexp64(nb, src[0],
>
> &val->ssa->elems[1]->def);
> - else
> + else if (src[0]->bit_size == 32)
> val->ssa->elems[0]->def = build_frexp32(nb, src[0],
>
> &val->ssa->elems[1]->def);
> + else
> + val->ssa->elems[0]->def = build_frexp16(nb, src[0],
> +
> &val->ssa->elems[1]->def);
> return;
> }
>
> --
> 2.17.1
>
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