target/m68k: Explicitly set 2-NaN propagation rule

Explicitly set the 2-NaN propagation rule on env->fp_status
and on the temporary fp_status that we use in frem (since
we pass that to a division operation function).

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

fpu/softfloat-specialize.c.inc

@@ -404,25 +404,8 @@ 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_S390X) || defined(TARGET_PPC) || defined(TARGET_M68K)
         g_assert_not_reached();
-#elif defined(TARGET_M68K)
-        /*
-         * M68000 FAMILY PROGRAMMER'S REFERENCE MANUAL
-         * 3.4 FLOATING-POINT INSTRUCTION DETAILS
-         * If either operand, but not both operands, of an operation is a
-         * nonsignaling NaN, then that NaN is returned as the result. If both
-         * operands are nonsignaling NaNs, then the destination operand
-         * nonsignaling NaN is returned as the result.
-         * If either operand to an operation is a signaling NaN (SNaN), then the
-         * SNaN bit is set in the FPSR EXC byte. If the SNaN exception enable bit
-         * is set in the FPCR ENABLE byte, then the exception is taken and the
-         * destination is not modified. If the SNaN exception enable bit is not
-         * set, setting the SNaN bit in the operand to a one converts the SNaN to
-         * a nonsignaling NaN. The operation then continues as described in the
-         * preceding paragraph for nonsignaling NaNs.
-         */
-        rule = float_2nan_prop_ab;
 #elif defined(TARGET_SPARC)
         /* Prefer SNaN over QNaN, order B then A. */
         rule = float_2nan_prop_s_ba;

target/m68k/cpu.c

@@ -93,6 +93,22 @@ static void m68k_cpu_reset_hold(Object *obj, ResetType type)
         env->fregs[i].d = nan;
     }
     cpu_m68k_set_fpcr(env, 0);
+    /*
+     * M68000 FAMILY PROGRAMMER'S REFERENCE MANUAL
+     * 3.4 FLOATING-POINT INSTRUCTION DETAILS
+     * If either operand, but not both operands, of an operation is a
+     * nonsignaling NaN, then that NaN is returned as the result. If both
+     * operands are nonsignaling NaNs, then the destination operand
+     * nonsignaling NaN is returned as the result.
+     * If either operand to an operation is a signaling NaN (SNaN), then the
+     * SNaN bit is set in the FPSR EXC byte. If the SNaN exception enable bit
+     * is set in the FPCR ENABLE byte, then the exception is taken and the
+     * destination is not modified. If the SNaN exception enable bit is not
+     * set, setting the SNaN bit in the operand to a one converts the SNaN to
+     * a nonsignaling NaN. The operation then continues as described in the
+     * preceding paragraph for nonsignaling NaNs.
+     */
+    set_float_2nan_prop_rule(float_2nan_prop_ab, &env->fp_status);
     env->fpsr = 0;
 
     /* TODO: We should set PC from the interrupt vector.  */

target/m68k/fpu_helper.c

@@ -620,6 +620,7 @@ void HELPER(frem)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
         int sign;
 
         /* Calculate quotient directly using round to nearest mode */
+        set_float_2nan_prop_rule(float_2nan_prop_ab, &fp_status);
         set_float_rounding_mode(float_round_nearest_even, &fp_status);
         set_floatx80_rounding_precision(
             get_floatx80_rounding_precision(&env->fp_status), &fp_status);