Commit 41044b5475 for qemu.org

commit 41044b5475da078a0f988e83a8738626c37afee0
Author: Richard Henderson <richard.henderson@linaro.org>
Date:   Tue May 19 08:43:57 2026 -0700

    fpu: Introduce float_status.e4m3_nan_is_snan

    Introduce a separate control from float_snan_rule
    that applies only to the OCP E4M3 format.

    Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
    Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index 184614ea47..559e40d196 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -246,7 +246,7 @@ static void partsN(canonicalize)(FloatPartsN *p, float_status *status,
         case float_expmax_e4m3:
             if (p->frac_hi == 0b111) {
                 fracN(shl)(p, fmt->frac_shift);
-                p->cls = (parts_is_snan_frac(p->frac_hi, status)
+                p->cls = (get_float_e4m3_nan_is_snan(status)
                           ? float_class_snan : float_class_qnan);
                 return;
             }
diff --git a/fpu/softfloat-specialize.c.inc b/fpu/softfloat-specialize.c.inc
index b97c971ae6..8b765ef623 100644
--- a/fpu/softfloat-specialize.c.inc
+++ b/fpu/softfloat-specialize.c.inc
@@ -104,6 +104,11 @@ static inline bool get_float_rebias_underflow(const float_status *status)
     return status->rebias_underflow;
 }

+static inline bool get_float_e4m3_nan_is_snan(const float_status *status)
+{
+    return status->e4m3_nan_is_snan;
+}
+
 /*----------------------------------------------------------------------------
 | For the deconstructed floating-point with fraction FRAC, return true
 | if the fraction represents a signalling NaN; otherwise false.
diff --git a/include/fpu/softfloat-helpers.h b/include/fpu/softfloat-helpers.h
index 4791a7fc87..8df0273132 100644
--- a/include/fpu/softfloat-helpers.h
+++ b/include/fpu/softfloat-helpers.h
@@ -131,6 +131,11 @@ static inline void set_snan_rule(FloatSNaNRule val, float_status *status)
     status->float_snan_rule = val;
 }

+static inline void set_float_e4m3_nan_is_snan(bool val, float_status *status)
+{
+    status->e4m3_nan_is_snan = val;
+}
+
 static inline void set_float_rebias_overflow(bool val, float_status *status)
 {
     status->rebias_overflow = val;
diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h
index c5a6684763..d7f5303a6b 100644
--- a/include/fpu/softfloat-types.h
+++ b/include/fpu/softfloat-types.h
@@ -431,6 +431,11 @@ typedef struct float_status {
     /* do we detect and flush denormal results before or after rounding? */
     bool ftz_before_rounding : 1;
     FloatSNaNRule float_snan_rule : 2;
+    /*
+     * Overriding float_snan_rule, is the single NaN representation for
+     * the OCP E4M3 format an SNaN or QNaN?
+     */
+    bool e4m3_nan_is_snan : 1;
     Float2NaNPropRule float_2nan_prop_rule : 3;
     Float3NaNPropRule float_3nan_prop_rule : 7;
     FloatInfZeroNaNRule float_infzeronan_rule: 3;