diff --git a/include/fpu/softfloat-helpers.h b/include/fpu/softfloat-helpers.h
index 8983c2748ec..90862f5cd22 100644
--- a/include/fpu/softfloat-helpers.h
+++ b/include/fpu/softfloat-helpers.h
@@ -75,6 +75,12 @@ static inline void set_floatx80_rounding_precision(FloatX80RoundPrec val,
     status->floatx80_rounding_precision = val;
 }
 
+static inline void set_floatx80_behaviour(FloatX80Behaviour b,
+                                          float_status *status)
+{
+    status->floatx80_behaviour = b;
+}
+
 static inline void set_float_2nan_prop_rule(Float2NaNPropRule rule,
                                             float_status *status)
 {
@@ -151,6 +157,12 @@ get_floatx80_rounding_precision(const float_status *status)
     return status->floatx80_rounding_precision;
 }
 
+static inline FloatX80Behaviour
+get_floatx80_behaviour(const float_status *status)
+{
+    return status->floatx80_behaviour;
+}
+
 static inline Float2NaNPropRule
 get_float_2nan_prop_rule(const float_status *status)
 {
diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h
index 53d5eb85210..dd22ecdbe60 100644
--- a/include/fpu/softfloat-types.h
+++ b/include/fpu/softfloat-types.h
@@ -320,6 +320,18 @@ typedef enum __attribute__((__packed__)) {
     float_ftz_before_rounding = 1,
 } FloatFTZDetection;
 
+/*
+ * floatx80 is primarily used by x86 and m68k, and there are
+ * differences in the handling, largely related to the explicit
+ * Integer bit which floatx80 has and the other float formats do not.
+ * These flag values allow specification of the target's requirements
+ * and can be ORed together to set floatx80_behaviour.
+ */
+typedef enum __attribute__((__packed__)) {
+    /* In the default Infinity value, is the Integer bit 0 ? */
+    floatx80_default_inf_int_bit_is_zero = 1,
+} FloatX80Behaviour;
+
 /*
  * Floating Point Status. Individual architectures may maintain
  * several versions of float_status for different functions. The
@@ -331,6 +343,7 @@ typedef struct float_status {
     uint16_t float_exception_flags;
     FloatRoundMode float_rounding_mode;
     FloatX80RoundPrec floatx80_rounding_precision;
+    FloatX80Behaviour floatx80_behaviour;
     Float2NaNPropRule float_2nan_prop_rule;
     Float3NaNPropRule float_3nan_prop_rule;
     FloatInfZeroNaNRule float_infzeronan_rule;
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 09a40b43106..afae3906024 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -961,6 +961,7 @@ float128 floatx80_to_float128(floatx80, float_status *status);
 | The pattern for an extended double-precision inf.
 *----------------------------------------------------------------------------*/
 extern const floatx80 floatx80_infinity;
+floatx80 floatx80_default_inf(bool zSign, float_status *status);
 
 /*----------------------------------------------------------------------------
 | Software IEC/IEEE extended double-precision operations.
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index f4fed9bfda9..b12ad2b42a9 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -1860,7 +1860,8 @@ static floatx80 floatx80_round_pack_canonical(FloatParts128 *p,
 
     case float_class_inf:
         /* x86 and m68k differ in the setting of the integer bit. */
-        frac = floatx80_infinity_low;
+        frac = s->floatx80_behaviour & floatx80_default_inf_int_bit_is_zero ?
+            0 : (1ULL << 63);
         exp = fmt->exp_max;
         break;
 
@@ -5144,9 +5145,7 @@ floatx80 roundAndPackFloatx80(FloatX80RoundPrec roundingPrecision, bool zSign,
                ) {
                 return packFloatx80( zSign, 0x7FFE, ~ roundMask );
             }
-            return packFloatx80(zSign,
-                                floatx80_infinity_high,
-                                floatx80_infinity_low);
+            return floatx80_default_inf(zSign, status);
         }
         if ( zExp <= 0 ) {
             isTiny = status->tininess_before_rounding
diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c
index 41dfdf58045..df66e8ba22a 100644
--- a/target/m68k/cpu.c
+++ b/target/m68k/cpu.c
@@ -107,6 +107,12 @@ static void m68k_cpu_reset_hold(Object *obj, ResetType type)
     set_float_2nan_prop_rule(float_2nan_prop_ab, &env->fp_status);
     /* Default NaN: sign bit clear, all frac bits set */
     set_float_default_nan_pattern(0b01111111, &env->fp_status);
+    /*
+     * m68k-specific floatx80 behaviour:
+     *  * default Infinity values have a zero Integer bit
+     */
+    set_floatx80_behaviour(floatx80_default_inf_int_bit_is_zero,
+                           &env->fp_status);
 
     nan = floatx80_default_nan(&env->fp_status);
     for (i = 0; i < 8; i++) {
diff --git a/fpu/softfloat-specialize.c.inc b/fpu/softfloat-specialize.c.inc
index cbbbab52ba3..73789e97d77 100644
--- a/fpu/softfloat-specialize.c.inc
+++ b/fpu/softfloat-specialize.c.inc
@@ -227,6 +227,16 @@ floatx80 floatx80_default_nan(float_status *status)
 | The pattern for a default generated extended double-precision inf.
 *----------------------------------------------------------------------------*/
 
+floatx80 floatx80_default_inf(bool zSign, float_status *status)
+{
+    /*
+     * Whether the Integer bit is set in the default Infinity is
+     * target dependent.
+     */
+    bool z = status->floatx80_behaviour & floatx80_default_inf_int_bit_is_zero;
+    return packFloatx80(zSign, 0x7fff, z ? 0 : (1ULL << 63));
+}
+
 #define floatx80_infinity_high 0x7FFF
 #if defined(TARGET_M68K)
 #define floatx80_infinity_low  UINT64_C(0x0000000000000000)
