target/sparc: Explicitly set 2-NaN propagation rule

Set the NaN propagation rule explicitly in the float_status
words we use.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241025141254.2141506-13-peter.maydell@linaro.org

fpu/softfloat-specialize.c.inc

@@ -404,11 +404,9 @@ static int pickNaN(FloatClass a_cls, FloatClass b_cls,
     || defined(TARGET_RISCV) || defined(TARGET_SH4) \
     || defined(TARGET_TRICORE) || defined(TARGET_ARM) || defined(TARGET_MIPS) \
     || defined(TARGET_LOONGARCH64) || defined(TARGET_HPPA) \
-    || defined(TARGET_S390X) || defined(TARGET_PPC) || defined(TARGET_M68K)
+    || defined(TARGET_S390X) || defined(TARGET_PPC) || defined(TARGET_M68K) \
+    || defined(TARGET_SPARC)
         g_assert_not_reached();
-#elif defined(TARGET_SPARC)
-        /* Prefer SNaN over QNaN, order B then A. */
-        rule = float_2nan_prop_s_ba;
 #elif defined(TARGET_XTENSA)
         /*
          * Xtensa has two NaN propagation modes.

target/sparc/cpu.c

@@ -26,6 +26,7 @@
 #include "hw/qdev-properties.h"
 #include "qapi/visitor.h"
 #include "tcg/tcg.h"
+#include "fpu/softfloat.h"
 
 //#define DEBUG_FEATURES
 
@@ -807,6 +808,13 @@ static void sparc_cpu_realizefn(DeviceState *dev, Error **errp)
     env->version |= env->def.nwindows - 1;
 #endif
 
+    /*
+     * Prefer SNaN over QNaN, order B then A. It's OK to do this in realize
+     * rather than reset, because fp_status is after 'end_reset_fields' in
+     * the CPU state struct so it won't get zeroed on reset.
+     */
+    set_float_2nan_prop_rule(float_2nan_prop_s_ba, &env->fp_status);
+
     cpu_exec_realizefn(cs, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);

target/sparc/fop_helper.c

@@ -497,7 +497,10 @@ uint32_t helper_flcmps(float32 src1, float32 src2)
      * Perform the comparison with a dummy fp environment.
      */
     float_status discard = { };
-    FloatRelation r = float32_compare_quiet(src1, src2, &discard);
+    FloatRelation r;
+
+    set_float_2nan_prop_rule(float_2nan_prop_s_ba, &discard);
+    r = float32_compare_quiet(src1, src2, &discard);
 
     switch (r) {
     case float_relation_equal:
@@ -518,7 +521,10 @@ uint32_t helper_flcmps(float32 src1, float32 src2)
 uint32_t helper_flcmpd(float64 src1, float64 src2)
 {
     float_status discard = { };
-    FloatRelation r = float64_compare_quiet(src1, src2, &discard);
+    FloatRelation r;
+
+    set_float_2nan_prop_rule(float_2nan_prop_s_ba, &discard);
+    r = float64_compare_quiet(src1, src2, &discard);
 
     switch (r) {
     case float_relation_equal: