pickNaNMulAdd logic on Xtensa is to apply pickNaN to the inputs of the
expression (a * b) + c. However if default NaN is produces as a result
of (a * b) calculation it is not considered when c is NaN.
So with two pickNaN variants there must be two pickNaNMulAdd variants.
In addition the invalid flag is always set when (a * b) produces NaN.
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: "Alex Bennée" <alex.bennee@linaro.org>
Cc: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
Changes v2->v3:
- handle infzero case in pickNaNMulAdd properly and reword commit
message
fpu/softfloat-specialize.inc.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/fpu/softfloat-specialize.inc.c b/fpu/softfloat-specialize.inc.c
index f519beca1b74..914deac46ecf 100644
--- a/fpu/softfloat-specialize.inc.c
+++ b/fpu/softfloat-specialize.inc.c
@@ -585,6 +585,32 @@ static int pickNaNMulAdd(FloatClass a_cls, FloatClass b_cls, FloatClass c_cls,
} else {
return 1;
}
+#elif defined(TARGET_XTENSA)
+ /*
+ * For Xtensa, the (inf,zero,nan) case sets InvalidOp and returns
+ * an input NaN if we have one (ie c).
+ */
+ if (infzero) {
+ float_raise(float_flag_invalid, status);
+ return 2;
+ }
+ if (status->use_first_nan) {
+ if (is_nan(a_cls)) {
+ return 0;
+ } else if (is_nan(b_cls)) {
+ return 1;
+ } else {
+ return 2;
+ }
+ } else {
+ if (is_nan(c_cls)) {
+ return 2;
+ } else if (is_nan(b_cls)) {
+ return 1;
+ } else {
+ return 0;
+ }
+ }
#else
/* A default implementation: prefer a to b to c.
* This is unlikely to actually match any real implementation.
--
2.20.1