David Hildenbrand <david@redhat.com> writes:
Implementation inspired by minmax_floats(). Unfortuantely, we don't have
any tests we can simply adjust/unlock.
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: "Alex Bennée" <alex.bennee@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
fpu/softfloat.c | 100 ++++++++++++++++++++++++++++++++++++++++
include/fpu/softfloat.h | 6 +++
2 files changed, 106 insertions(+)
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 9af75b9146..9463c5ea56 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -621,6 +621,8 @@ static inline FloatParts float64_unpack_raw(float64 f)
return unpack_raw(float64_params, f);
}
+static void float128_unpack(FloatParts128 *p, float128 a,
float_status *status);
+
/* Pack a float from parts, but do not canonicalize. */
static inline uint64_t pack_raw(FloatFmt fmt, FloatParts p)
{
@@ -3180,6 +3182,89 @@ static FloatParts minmax_floats(FloatParts a, FloatParts
b, bool ismin,
}
}
It would be desirable to share as much logic for this as possible with
the existing minmax_floats code. I appreciate at some point we end up
having to deal with fractions and we haven't found a good way to
efficiently handle dealing with FloatParts and FloatParts128 in the same
unrolled code, however:
+static float128 float128_minmax(float128 a, float128 b, bool
ismin, bool ieee,
+ bool ismag, float_status *s)
+{
+ FloatParts128 pa, pb;
+ int a_exp, b_exp;
+ bool a_less;
+
+ float128_unpack(&pa, a, s);
+ float128_unpack(&pb, b, s);
+
From here:
+ if (unlikely(is_nan(pa.cls) || is_nan(pb.cls))) {
+ /* See comment in minmax_floats() */
+ if (ieee && !is_snan(pa.cls) && !is_snan(pb.cls)) {
+ if (is_nan(pa.cls) && !is_nan(pb.cls)) {
+ return b;
+ } else if (is_nan(pb.cls) && !is_nan(pa.cls)) {
+ return a;
+ }
+ }
+
+ /* Similar logic to pick_nan(), avoiding re-packing. */
+ if (is_snan(pa.cls) || is_snan(pb.cls)) {
+ s->float_exception_flags |= float_flag_invalid;
+ }
+ if (s->default_nan_mode) {
+ return float128_default_nan(s);
+ }
to here is common logic - is there anyway we could share it?