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-rw-r--r--target/ppc/cpu_init.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index efcb80d1c2..1253dbf622 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -7270,6 +7270,25 @@ static void ppc_cpu_reset_hold(Object *obj, ResetType type)
      */
     set_float_2nan_prop_rule(float_2nan_prop_ab, &env->fp_status);
     set_float_2nan_prop_rule(float_2nan_prop_ab, &env->vec_status);
+    /*
+     * NaN propagation for fused multiply-add:
+     * if fRA is a NaN return it; otherwise if fRB is a NaN return it;
+     * otherwise return fRC. Note that muladd on PPC is (fRA * fRC) + frB
+     * whereas QEMU labels the operands as (a * b) + c.
+     */
+    set_float_3nan_prop_rule(float_3nan_prop_acb, &env->fp_status);
+    set_float_3nan_prop_rule(float_3nan_prop_acb, &env->vec_status);
+    /*
+     * For PPC, the (inf,zero,qnan) case sets InvalidOp, but we prefer
+     * to return an input NaN if we have one (ie c) rather than generating
+     * a default NaN
+     */
+    set_float_infzeronan_rule(float_infzeronan_dnan_never, &env->fp_status);
+    set_float_infzeronan_rule(float_infzeronan_dnan_never, &env->vec_status);
+
+    /* Default NaN: sign bit clear, set frac msb */
+    set_float_default_nan_pattern(0b01000000, &env->fp_status);
+    set_float_default_nan_pattern(0b01000000, &env->vec_status);
 
     for (i = 0; i < ARRAY_SIZE(env->spr_cb); i++) {
         ppc_spr_t *spr = &env->spr_cb[i];