We convert from doubles to half by going through float in between, but
as noted in the comment in this commit, that can give wrong results in
some cases.
Add some helpers to ensure correct results based on rounding mode that
will be used in the next commit.
v2: Use fi/di from u_math.h (Ian)
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25281>
In order to be coherent with the pre-existent API for half floats,
this new API for double is the one meant to be used when doing double
to float conversions. It is no more than a wrapper for the softfloat.h
API but we meant to keep that one private.
v2:
- Fix bug in _mesa_double_to_float_rtz() in the inf/nan detection
using the exponent value.
v3:
- Replace custom f64 -> f32 implementations with the softfloat
one (Andres).
v4:
- Added API usage clarifying comments (Caio).
Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Signed-off-by: Andres Gomez <agomez@igalia.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
