Add MRB_WORD_BOXING mode (represent mrb_value as a word)

15 files changed, 411 insertions, 146 deletions

diff --git a/include/mrbconf.h b/include/mrbconf.h
index 2b9cc5e60..0d65ae13a 100644
--- a/include/mrbconf.h
+++ b/include/mrbconf.h
@@ -26,6 +26,9 @@
 /* define on big endian machines; used by MRB_NAN_BOXING */
 //#define MRB_ENDIAN_BIG
 
+/* represent mrb_value as a word (natural unit of data for the processor) */
+// #define MRB_WORD_BOXING
+
 /* argv max size in mrb_funcall */
 //#define MRB_FUNCALL_ARGC_MAX 16
 
diff --git a/include/mruby.h b/include/mruby.h
index fac7e6fcd..f9f448b45 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -273,11 +273,11 @@ int mrb_gc_arena_save(mrb_state*);
 void mrb_gc_arena_restore(mrb_state*,int);
 void mrb_gc_mark(mrb_state*,struct RBasic*);
 #define mrb_gc_mark_value(mrb,val) do {\
-  if (mrb_type(val) >= MRB_TT_OBJECT) mrb_gc_mark((mrb), mrb_basic_ptr(val));\
+  if (mrb_type(val) >= MRB_TT_HAS_BASIC) mrb_gc_mark((mrb), mrb_basic_ptr(val));\
 } while (0)
 void mrb_field_write_barrier(mrb_state *, struct RBasic*, struct RBasic*);
 #define mrb_field_write_barrier_value(mrb, obj, val) do{\
-  if ((val.tt >= MRB_TT_OBJECT)) mrb_field_write_barrier((mrb), (obj), mrb_basic_ptr(val));\
+  if ((val.tt >= MRB_TT_HAS_BASIC)) mrb_field_write_barrier((mrb), (obj), mrb_basic_ptr(val));\
 } while (0)
 void mrb_write_barrier(mrb_state *, struct RBasic*);
 
diff --git a/include/mruby/value.h b/include/mruby/value.h
index fa2a68ac8..d4030ed2d 100644
--- a/include/mruby/value.h
+++ b/include/mruby/value.h
@@ -8,63 +8,9 @@
 #define MRUBY_VALUE_H
 
 typedef uint8_t mrb_bool;
+struct mrb_state;
 
-#ifndef MRB_NAN_BOXING
-
-enum mrb_vtype {
-  MRB_TT_FALSE = 0,   /*   0 */
-  MRB_TT_FREE,        /*   1 */
-  MRB_TT_TRUE,        /*   2 */
-  MRB_TT_FIXNUM,      /*   3 */
-  MRB_TT_SYMBOL,      /*   4 */
-  MRB_TT_UNDEF,       /*   5 */
-  MRB_TT_FLOAT,       /*   6 */
-  MRB_TT_VOIDP,       /*   7 */
-  MRB_TT_OBJECT,      /*   8 */
-  MRB_TT_CLASS,       /*   9 */
-  MRB_TT_MODULE,      /*  10 */
-  MRB_TT_ICLASS,      /*  11 */
-  MRB_TT_SCLASS,      /*  12 */
-  MRB_TT_PROC,        /*  13 */
-  MRB_TT_ARRAY,       /*  14 */
-  MRB_TT_HASH,        /*  15 */
-  MRB_TT_STRING,      /*  16 */
-  MRB_TT_RANGE,       /*  17 */
-  MRB_TT_EXCEPTION,   /*  18 */
-  MRB_TT_FILE,        /*  19 */
-  MRB_TT_ENV,         /*  20 */
-  MRB_TT_DATA,        /*  21 */
-  MRB_TT_FIBER,       /*  22 */
-  MRB_TT_MAXDEFINE    /*  23 */
-};
-
-typedef struct mrb_value {
-  union {
-    mrb_float f;
-    void *p;
-    mrb_int i;
-    mrb_sym sym;
-  } value;
-  enum mrb_vtype tt;
-} mrb_value;
-
-#define mrb_type(o)   (o).tt
-#define mrb_float(o)  (o).value.f
-
-#define MRB_SET_VALUE(o, ttt, attr, v) do {\
-  (o).tt = ttt;\
-  (o).attr = v;\
-} while (0)
-
-static inline mrb_value
-mrb_float_value(mrb_float f)
-{
-  mrb_value v;
-
-  MRB_SET_VALUE(v, MRB_TT_FLOAT, value.f, f);
-  return v;
-}
-#else  /* MRB_NAN_BOXING */
+#if defined(MRB_NAN_BOXING)
 
 #ifdef MRB_USE_FLOAT
 # error ---->> MRB_NAN_BOXING and MRB_USE_FLOAT conflict <<----
@@ -97,6 +43,8 @@ enum mrb_vtype {
   MRB_TT_MAXDEFINE    /*  24 */
 };
 
+#define MRB_TT_HAS_BASIC  MRB_TT_OBJECT
+
 #ifdef MRB_ENDIAN_BIG
 #define MRB_ENDIAN_LOHI(a,b) a b
 #else
@@ -130,7 +78,7 @@ typedef struct mrb_value {
 } while (0)
 
 static inline mrb_value
-mrb_float_value(mrb_float f)
+mrb_float_value(struct mrb_state *mrb, mrb_float f)
 {
   mrb_value v;
 
@@ -142,7 +90,163 @@ mrb_float_value(mrb_float f)
   }
   return v;
 }
-#endif	/* MRB_NAN_BOXING */
+
+#elif defined(MRB_WORD_BOXING)
+
+enum mrb_vtype {
+  MRB_TT_FALSE = 0,   /*   0 */
+  MRB_TT_FREE,        /*   1 */
+  MRB_TT_TRUE,        /*   2 */
+  MRB_TT_FIXNUM,      /*   3 */
+  MRB_TT_SYMBOL,      /*   4 */
+  MRB_TT_UNDEF,       /*   5 */
+  MRB_TT_FLOAT,       /*   6 */
+  MRB_TT_VOIDP,       /*   7 */
+  MRB_TT_OBJECT,      /*   8 */
+  MRB_TT_CLASS,       /*   9 */
+  MRB_TT_MODULE,      /*  10 */
+  MRB_TT_ICLASS,      /*  11 */
+  MRB_TT_SCLASS,      /*  12 */
+  MRB_TT_PROC,        /*  13 */
+  MRB_TT_ARRAY,       /*  14 */
+  MRB_TT_HASH,        /*  15 */
+  MRB_TT_STRING,      /*  16 */
+  MRB_TT_RANGE,       /*  17 */
+  MRB_TT_EXCEPTION,   /*  18 */
+  MRB_TT_FILE,        /*  19 */
+  MRB_TT_ENV,         /*  20 */
+  MRB_TT_DATA,        /*  21 */
+  MRB_TT_FIBER,       /*  22 */
+  MRB_TT_MAXDEFINE    /*  23 */
+};
+
+#define MRB_TT_HAS_BASIC  MRB_TT_FLOAT
+
+enum mrb_special_consts {
+  MRB_Qnil    = 0,
+  MRB_Qfalse  = 2,
+  MRB_Qtrue   = 4,
+  MRB_Qundef  = 6,
+
+  MRB_FIXNUM_FLAG   = 0x01,
+  MRB_FIXNUM_SHIFT  = 1,
+  MRB_SYMBOL_FLAG   = 0x0e,
+  MRB_SPECIAL_SHIFT = 8,
+};
+
+typedef union mrb_value {
+  union {
+    void *p;
+    struct {
+      unsigned int i_flag : MRB_FIXNUM_SHIFT;
+      mrb_int i : (sizeof(mrb_int) * 8 - MRB_FIXNUM_SHIFT);
+    };
+    struct {
+      unsigned int sym_flag : MRB_SPECIAL_SHIFT;
+      int sym : (sizeof(mrb_sym) * 8);
+    };
+    struct RBasic *bp;
+    struct RFloat *fp;
+    struct RVoidp *vp;
+  } value;
+  unsigned long w;
+} mrb_value;
+
+#define mrb_float(o)  (o).value.fp->f
+
+#define MRB_SET_VALUE(o, ttt, attr, v) do {\
+  (o).w = 0;\
+  (o).attr = (v);\
+  switch (ttt) {\
+  case MRB_TT_FALSE:  (o).w = (v) ? MRB_Qfalse : MRB_Qnil; break;\
+  case MRB_TT_TRUE:   (o).w = MRB_Qtrue; break;\
+  case MRB_TT_UNDEF:  (o).w = MRB_Qundef; break;\
+  case MRB_TT_FIXNUM: (o).value.i_flag = MRB_FIXNUM_FLAG; break;\
+  case MRB_TT_SYMBOL: (o).value.sym_flag = MRB_SYMBOL_FLAG; break;\
+  default:            if ((o).value.bp) (o).value.bp->tt = ttt; break;\
+  }\
+} while (0)
+
+extern mrb_value
+mrb_float_value(struct mrb_state *mrb, mrb_float f);
+
+#else /* No MRB_xxx_BOXING */
+
+enum mrb_vtype {
+  MRB_TT_FALSE = 0,   /*   0 */
+  MRB_TT_FREE,        /*   1 */
+  MRB_TT_TRUE,        /*   2 */
+  MRB_TT_FIXNUM,      /*   3 */
+  MRB_TT_SYMBOL,      /*   4 */
+  MRB_TT_UNDEF,       /*   5 */
+  MRB_TT_FLOAT,       /*   6 */
+  MRB_TT_VOIDP,       /*   7 */
+  MRB_TT_OBJECT,      /*   8 */
+  MRB_TT_CLASS,       /*   9 */
+  MRB_TT_MODULE,      /*  10 */
+  MRB_TT_ICLASS,      /*  11 */
+  MRB_TT_SCLASS,      /*  12 */
+  MRB_TT_PROC,        /*  13 */
+  MRB_TT_ARRAY,       /*  14 */
+  MRB_TT_HASH,        /*  15 */
+  MRB_TT_STRING,      /*  16 */
+  MRB_TT_RANGE,       /*  17 */
+  MRB_TT_EXCEPTION,   /*  18 */
+  MRB_TT_FILE,        /*  19 */
+  MRB_TT_ENV,         /*  20 */
+  MRB_TT_DATA,        /*  21 */
+  MRB_TT_FIBER,       /*  22 */
+  MRB_TT_MAXDEFINE    /*  23 */
+};
+
+#define MRB_TT_HAS_BASIC  MRB_TT_OBJECT
+
+typedef struct mrb_value {
+  union {
+    mrb_float f;
+    void *p;
+    mrb_int i;
+    mrb_sym sym;
+  } value;
+  enum mrb_vtype tt;
+} mrb_value;
+
+#define mrb_type(o)   (o).tt
+#define mrb_float(o)  (o).value.f
+
+#define MRB_SET_VALUE(o, ttt, attr, v) do {\
+  (o).tt = ttt;\
+  (o).attr = v;\
+} while (0)
+
+static inline mrb_value
+mrb_float_value(struct mrb_state *mrb, mrb_float f)
+{
+  mrb_value v;
+
+  MRB_SET_VALUE(v, MRB_TT_FLOAT, value.f, f);
+  return v;
+}
+#endif  /* no boxing */
+
+#ifdef MRB_WORD_BOXING
+
+#define mrb_fixnum(o) (o).value.i
+#define mrb_symbol(o) (o).value.sym
+#define mrb_voidp(o) (o).value.vp->p
+#define mrb_fixnum_p(o) ((o).value.i_flag == MRB_FIXNUM_FLAG)
+#define mrb_float_p(o) (mrb_type(o) == MRB_TT_FLOAT)
+#define mrb_undef_p(o) ((o).w == MRB_Qundef)
+#define mrb_nil_p(o)  ((o).w == MRB_Qnil)
+#define mrb_symbol_p(o) ((o).value.sym_flag == MRB_SYMBOL_FLAG)
+#define mrb_array_p(o) (mrb_type(o) == MRB_TT_ARRAY)
+#define mrb_string_p(o) (mrb_type(o) == MRB_TT_STRING)
+#define mrb_hash_p(o) (mrb_type(o) == MRB_TT_HASH)
+#define mrb_voidp_p(o) (mrb_type(o) == MRB_TT_VOIDP)
+#define mrb_bool(o)   ((o).w != MRB_Qnil && (o).w != MRB_Qfalse)
+#define mrb_test(o)   mrb_bool(o)
+
+#else
 
 #define mrb_fixnum(o) (o).value.i
 #define mrb_symbol(o) (o).value.sym
@@ -159,6 +263,8 @@ mrb_float_value(mrb_float f)
 #define mrb_bool(o)   (mrb_type(o) != MRB_TT_FALSE)
 #define mrb_test(o)   mrb_bool(o)
 
+#endif  /* no boxing */
+
 #define MRB_OBJECT_HEADER \
   enum mrb_vtype tt:8;\
   uint32_t color:3;\
@@ -209,6 +315,39 @@ struct RFiber {
   struct mrb_context *cxt;
 };
 
+#ifdef MRB_WORD_BOXING
+struct RFloat {
+  MRB_OBJECT_HEADER;
+  mrb_float f;
+};
+
+struct RVoidp {
+  MRB_OBJECT_HEADER;
+  void *p;
+};
+
+static inline enum mrb_vtype
+mrb_type(mrb_value o)
+{
+  switch (o.w) {
+  case MRB_Qfalse:
+  case MRB_Qnil:
+    return MRB_TT_FALSE;
+  case MRB_Qtrue:
+    return MRB_TT_TRUE;
+  case MRB_Qundef:
+    return MRB_TT_UNDEF;
+  }
+  if (o.value.i_flag == MRB_FIXNUM_FLAG) {
+    return MRB_TT_FIXNUM;
+  }
+  if (o.value.sym_flag == MRB_SYMBOL_FLAG) {
+    return MRB_TT_SYMBOL;
+  }
+  return o.value.bp->tt;
+}
+#endif  /* MRB_WORD_BOXING */
+
 static inline mrb_value
 mrb_fixnum_value(mrb_int i)
 {
@@ -237,14 +376,19 @@ mrb_obj_value(void *p)
   return v;
 }
 
+#ifdef MRB_WORD_BOXING
+mrb_value
+mrb_voidp_value(struct mrb_state *mrb, void *p);
+#else
 static inline mrb_value
-mrb_voidp_value(void *p)
+mrb_voidp_value(struct mrb_state *mrb, void *p)
 {
   mrb_value v;
 
   MRB_SET_VALUE(v, MRB_TT_VOIDP, value.p, p);
   return v;
 }
+#endif
 
 static inline mrb_value
 mrb_false_value(void)
diff --git a/mrbgems/mruby-math/src/math.c b/mrbgems/mruby-math/src/math.c
index 561d80178..bf3c007b4 100644
--- a/mrbgems/mruby-math/src/math.c
+++ b/mrbgems/mruby-math/src/math.c
@@ -108,7 +108,7 @@ math_sin(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = sin(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -126,7 +126,7 @@ math_cos(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = cos(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -143,7 +143,7 @@ math_tan(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = tan(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -164,7 +164,7 @@ math_asin(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = asin(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -181,7 +181,7 @@ math_acos(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = acos(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -198,7 +198,7 @@ math_atan(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = atan(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -228,7 +228,7 @@ math_atan2(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "ff", &x, &y);
   x = atan2(x, y);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 
@@ -251,7 +251,7 @@ math_sinh(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = sinh(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -268,7 +268,7 @@ math_cosh(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = cosh(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -286,7 +286,7 @@ math_tanh(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = tanh(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 
@@ -309,7 +309,7 @@ math_asinh(mrb_state *mrb, mrb_value obj)
 
   x = asinh(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -326,7 +326,7 @@ math_acosh(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = acosh(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -343,7 +343,7 @@ math_atanh(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = atanh(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -389,7 +389,7 @@ math_exp(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = exp(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -418,7 +418,7 @@ math_log(mrb_state *mrb, mrb_value obj)
   if (argc == 2) {
     x /= log(base);
   }
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -441,7 +441,7 @@ math_log2(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = log2(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -463,7 +463,7 @@ math_log10(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = log10(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -481,7 +481,7 @@ math_sqrt(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = sqrt(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 
@@ -524,7 +524,7 @@ math_cbrt(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = cbrt(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 
@@ -548,7 +548,7 @@ math_frexp(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = frexp(x, &exp);
 
-  return mrb_assoc_new(mrb, mrb_float_value(x), mrb_fixnum_value(exp));
+  return mrb_assoc_new(mrb, mrb_float_value(mrb, x), mrb_fixnum_value(exp));
 }
 
 /*
@@ -569,7 +569,7 @@ math_ldexp(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "fi", &x, &i);
   x = ldexp(x, i);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -589,7 +589,7 @@ math_hypot(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "ff", &x, &y);
   x = hypot(x, y);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /*
@@ -606,7 +606,7 @@ math_erf(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = erf(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 
@@ -624,7 +624,7 @@ math_erfc(mrb_state *mrb, mrb_value obj)
   mrb_get_args(mrb, "f", &x);
   x = erfc(x);
 
-  return mrb_float_value(x);
+  return mrb_float_value(mrb, x);
 }
 
 /* ------------------------------------------------------------------------*/
@@ -635,21 +635,21 @@ mrb_mruby_math_gem_init(mrb_state* mrb)
   mrb_math = mrb_define_module(mrb, "Math");
 
 #ifdef M_PI
-  mrb_define_const(mrb, mrb_math, "PI", mrb_float_value(M_PI));
+  mrb_define_const(mrb, mrb_math, "PI", mrb_float_value(mrb, M_PI));
 #else
-  mrb_define_const(mrb, mrb_math, "PI", mrb_float_value(atan(1.0)*4.0));
+  mrb_define_const(mrb, mrb_math, "PI", mrb_float_value(mrb, atan(1.0)*4.0));
 #endif
 
 #ifdef M_E
-  mrb_define_const(mrb, mrb_math, "E", mrb_float_value(M_E));
+  mrb_define_const(mrb, mrb_math, "E", mrb_float_value(mrb, M_E));
 #else
-  mrb_define_const(mrb, mrb_math, "E", mrb_float_value(exp(1.0)));
+  mrb_define_const(mrb, mrb_math, "E", mrb_float_value(mrb, exp(1.0)));
 #endif
 
 #ifdef MRB_USE_FLOAT
-  mrb_define_const(mrb, mrb_math, "TOLERANCE", mrb_float_value(1e-5));
+  mrb_define_const(mrb, mrb_math, "TOLERANCE", mrb_float_value(mrb, 1e-5));
 #else
-  mrb_define_const(mrb, mrb_math, "TOLERANCE", mrb_float_value(1e-12));
+  mrb_define_const(mrb, mrb_math, "TOLERANCE", mrb_float_value(mrb, 1e-12));
 #endif
 
   mrb_define_module_function(mrb, mrb_math, "sin", math_sin, MRB_ARGS_REQ(1));
diff --git a/mrbgems/mruby-random/src/random.c b/mrbgems/mruby-random/src/random.c
index b2a9926bd..13b4fa7a3 100644
--- a/mrbgems/mruby-random/src/random.c
+++ b/mrbgems/mruby-random/src/random.c
@@ -66,7 +66,7 @@ static mrb_value mrb_random_mt_g_rand(mrb_state *mrb, mrb_value max)
   mrb_value value;
 
   if (mrb_fixnum(max) == 0) {
-    value = mrb_float_value(mt_g_rand_real());
+    value = mrb_float_value(mrb, mt_g_rand_real());
   } else {
     value = mrb_fixnum_value(mt_g_rand() % mrb_fixnum(max));
   }
@@ -108,7 +108,7 @@ static mrb_value mrb_random_mt_rand(mrb_state *mrb, mt_state *t, mrb_value max)
   mrb_value value;
 
   if (mrb_fixnum(max) == 0) {
-    value = mrb_float_value(mt_rand_real(t));
+    value = mrb_float_value(mrb, mt_rand_real(t));
   } else {
     value = mrb_fixnum_value(mt_rand(t) % mrb_fixnum(max));
   }
diff --git a/mrbgems/mruby-time/src/time.c b/mrbgems/mruby-time/src/time.c
index 6a44590a8..2a2aabe72 100644
--- a/mrbgems/mruby-time/src/time.c
+++ b/mrbgems/mruby-time/src/time.c
@@ -358,7 +358,7 @@ mrb_time_minus(mrb_state *mrb, mrb_value self)
   if (tm2) {
     f = (mrb_float)(tm->sec - tm2->sec)
       + (mrb_float)(tm->usec - tm2->usec) / 1.0e6;
-    return mrb_float_value(f);
+    return mrb_float_value(mrb, f);
   }
   else {
     mrb_get_args(mrb, "f", &f);
@@ -628,7 +628,7 @@ mrb_time_to_f(mrb_state *mrb, mrb_value self)
 
   tm = (struct mrb_time*)mrb_data_get_ptr(mrb, self, &mrb_time_type);
   if (!tm) return mrb_nil_value();
-  return mrb_float_value((mrb_float)tm->sec + (mrb_float)tm->usec/1.0e6);
+  return mrb_float_value(mrb, (mrb_float)tm->sec + (mrb_float)tm->usec/1.0e6);
 }
 
 /* 15.2.19.7.25 */
diff --git a/src/codegen.c b/src/codegen.c
index 581d13280..cfbbe7286 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -1901,7 +1901,7 @@ codegen(codegen_scope *s, node *tree, int val)
       i = readint_mrb_int(s, p, base, FALSE, &overflow);
       if (overflow) {
         double f = readint_float(s, p, base);
-        int off = new_lit(s, mrb_float_value(f));
+        int off = new_lit(s, mrb_float_value(s->mrb, f));
 
         genop(s, MKOP_ABx(OP_LOADL, cursp(), off));
       }
@@ -1923,7 +1923,7 @@ codegen(codegen_scope *s, node *tree, int val)
     if (val) {
       char *p = (char*)tree;
       mrb_float f = str_to_mrb_float(p);
-      int off = new_lit(s, mrb_float_value(f));
+      int off = new_lit(s, mrb_float_value(s->mrb, f));
 
       genop(s, MKOP_ABx(OP_LOADL, cursp(), off));
       push();
@@ -1939,7 +1939,7 @@ codegen(codegen_scope *s, node *tree, int val)
         {
           char *p = (char*)tree;
           mrb_float f = str_to_mrb_float(p);
-          int off = new_lit(s, mrb_float_value(-f));
+          int off = new_lit(s, mrb_float_value(s->mrb, -f));
 
           genop(s, MKOP_ABx(OP_LOADL, cursp(), off));
           push();
@@ -1957,7 +1957,7 @@ codegen(codegen_scope *s, node *tree, int val)
           i = readint_mrb_int(s, p, base, TRUE, &overflow);
           if (overflow) {
             double f = readint_float(s, p, base);
-            int off = new_lit(s, mrb_float_value(-f));
+            int off = new_lit(s, mrb_float_value(s->mrb, -f));
 
             genop(s, MKOP_ABx(OP_LOADL, cursp(), off));
           }
diff --git a/src/etc.c b/src/etc.c
index f2ff34fec..2aee0f0f7 100644
--- a/src/etc.c
+++ b/src/etc.c
@@ -180,3 +180,25 @@ mrb_obj_id(mrb_value obj)
   }
 }
 
+#ifdef MRB_WORD_BOXING
+mrb_value
+mrb_float_value(mrb_state *mrb, mrb_float f)
+{
+  mrb_value v;
+
+  v.value.p = mrb_obj_alloc(mrb, MRB_TT_FLOAT, mrb->float_class);
+  v.value.fp->f = f;
+  return v;
+}
+
+mrb_value
+mrb_voidp_value(mrb_state *mrb, void *p)
+{
+  mrb_value v;
+
+  v.value.p = mrb_obj_alloc(mrb, MRB_TT_VOIDP, mrb->object_class);
+  v.value.vp->p = p;
+  return v;
+}
+#endif  /* MRB_WORD_BOXING */
+
diff --git a/src/gc.c b/src/gc.c
index 00ddadffc..6419726eb 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -530,10 +530,16 @@ obj_free(mrb_state *mrb, struct RBasic *obj)
   case MRB_TT_TRUE:
   case MRB_TT_FIXNUM:
   case MRB_TT_SYMBOL:
-  case MRB_TT_FLOAT:
     /* cannot happen */
     return;
 
+  case MRB_TT_FLOAT:
+#ifdef MRB_WORD_BOXING
+    break;
+#else
+    return;
+#endif
+
   case MRB_TT_OBJECT:
     mrb_gc_free_iv(mrb, (struct RObject*)obj);
     break;
diff --git a/src/kernel.c b/src/kernel.c
index af4806378..0fe374e73 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -894,7 +894,7 @@ mrb_f_raise(mrb_state *mrb, mrb_value self)
     /* fall through */
   default:
     exc = mrb_make_exception(mrb, argc, a);
-    mrb_obj_iv_set(mrb, mrb_obj_ptr(exc), mrb_intern2(mrb, "lastpc", 6), mrb_voidp_value(mrb->c->ci->pc));
+    mrb_obj_iv_set(mrb, mrb_obj_ptr(exc), mrb_intern2(mrb, "lastpc", 6), mrb_voidp_value(mrb, mrb->c->ci->pc));
     mrb_exc_raise(mrb, exc);
     break;
   }
diff --git a/src/load.c b/src/load.c
index 81d47858a..62010e425 100644
--- a/src/load.c
+++ b/src/load.c
@@ -130,7 +130,7 @@ read_rite_irep_record(mrb_state *mrb, const uint8_t *bin, uint32_t *len)
         break;
 
       case MRB_TT_FLOAT:
-        irep->pool[i] = mrb_float_value(mrb_str_to_dbl(mrb, s, FALSE));
+        irep->pool[i] = mrb_float_value(mrb, mrb_str_to_dbl(mrb, s, FALSE));
         break;
 
       case MRB_TT_STRING:
diff --git a/src/numeric.c b/src/numeric.c
index 14b4929e0..6b118dfb4 100644
--- a/src/numeric.c
+++ b/src/numeric.c
@@ -65,7 +65,7 @@ num_uplus(mrb_state *mrb, mrb_value num)
 static mrb_value
 num_uminus(mrb_state *mrb, mrb_value num)
 {
-  return mrb_float_value((mrb_float)0 - mrb_to_flo(mrb, num));
+  return mrb_float_value(mrb, (mrb_float)0 - mrb_to_flo(mrb, num));
 }
 
 static mrb_value
@@ -95,7 +95,7 @@ num_pow(mrb_state *mrb, mrb_value x)
   d = pow(mrb_to_flo(mrb, x), mrb_to_flo(mrb, y));
   if (both_int && FIXABLE(d))
     return mrb_fixnum_value((mrb_int)d);
-  return mrb_float_value(d);
+  return mrb_float_value(mrb, d);
 }
 
 /* 15.2.8.3.4  */
@@ -112,7 +112,7 @@ num_pow(mrb_state *mrb, mrb_value x)
 mrb_value
 mrb_num_div(mrb_state *mrb, mrb_value x, mrb_value y)
 {
-  return mrb_float_value(mrb_to_flo(mrb, x) / mrb_to_flo(mrb, y));
+  return mrb_float_value(mrb, mrb_to_flo(mrb, x) / mrb_to_flo(mrb, y));
 }
 
 /* 15.2.9.3.19(x) */
@@ -129,7 +129,7 @@ num_div(mrb_state *mrb, mrb_value x)
   mrb_float y;
 
   mrb_get_args(mrb, "f", &y);
-  return mrb_float_value(mrb_to_flo(mrb, x) / y);
+  return mrb_float_value(mrb, mrb_to_flo(mrb, x) / y);
 }
 
 /*
@@ -297,7 +297,7 @@ flo_minus(mrb_state *mrb, mrb_value x)
   mrb_value y;
 
   mrb_get_args(mrb, "o", &y);
-  return mrb_float_value(mrb_float(x) - mrb_to_flo(mrb, y));
+  return mrb_float_value(mrb, mrb_float(x) - mrb_to_flo(mrb, y));
 }
 
 /* 15.2.9.3.3  */
@@ -315,7 +315,7 @@ flo_mul(mrb_state *mrb, mrb_value x)
   mrb_value y;
 
   mrb_get_args(mrb, "o", &y);
-  return mrb_float_value(mrb_float(x) * mrb_to_flo(mrb, y));
+  return mrb_float_value(mrb, mrb_float(x) * mrb_to_flo(mrb, y));
 }
 
 static void
@@ -366,7 +366,7 @@ flo_mod(mrb_state *mrb, mrb_value x)
 
   fy = mrb_to_flo(mrb, y);
   flodivmod(mrb, mrb_float(x), fy, 0, &mod);
-  return mrb_float_value(mod);
+  return mrb_float_value(mrb, mod);
 }
 
 /* 15.2.8.3.16 */
@@ -545,7 +545,7 @@ flo_floor(mrb_state *mrb, mrb_value num)
   mrb_float f = floor(mrb_float(num));
 
   if (!FIXABLE(f)) {
-    return mrb_float_value(f);
+    return mrb_float_value(mrb, f);
   }
   return mrb_fixnum_value((mrb_int)f);
 }
@@ -570,7 +570,7 @@ flo_ceil(mrb_state *mrb, mrb_value num)
   mrb_float f = ceil(mrb_float(num));
 
   if (!FIXABLE(f)) {
-    return mrb_float_value(f);
+    return mrb_float_value(mrb, f);
   }
   return mrb_fixnum_value((mrb_int)f);
 }
@@ -642,7 +642,7 @@ flo_round(mrb_state *mrb, mrb_value num)
     if (ndigits < 0) number *= f;
     else number /= f;
   }
-  if (ndigits > 0) return mrb_float_value(number);
+  if (ndigits > 0) return mrb_float_value(mrb, number);
   return mrb_fixnum_value((mrb_int)number);
 }
 
@@ -666,7 +666,7 @@ flo_truncate(mrb_state *mrb, mrb_value num)
   if (f < 0.0) f = ceil(f);
 
   if (!FIXABLE(f)) {
-    return mrb_float_value(f);
+    return mrb_float_value(mrb, f);
   }
   return mrb_fixnum_value((mrb_int)f);
 }
@@ -750,11 +750,11 @@ mrb_fixnum_mul(mrb_state *mrb, mrb_value x, mrb_value y)
       return mrb_fixnum_value(a*b);
     c = a * b;
     if (a != 0 && c/a != b) {
-      return mrb_float_value((mrb_float)a*(mrb_float)b);
+      return mrb_float_value(mrb, (mrb_float)a*(mrb_float)b);
     }
     return mrb_fixnum_value(c);;
   }
-  return mrb_float_value((mrb_float)a * mrb_to_flo(mrb, y));
+  return mrb_float_value(mrb, (mrb_float)a * mrb_to_flo(mrb, y));
 }
 
 /* 15.2.8.3.3  */
@@ -826,7 +826,7 @@ fix_mod(mrb_state *mrb, mrb_value x)
     mrb_int mod;
 
     if (mrb_fixnum(y) == 0) {
-      return mrb_float_value(str_to_mrb_float("nan"));
+      return mrb_float_value(mrb, str_to_mrb_float("nan"));
     }
     fixdivmod(mrb, a, mrb_fixnum(y), 0, &mod);
     return mrb_fixnum_value(mod);
@@ -835,7 +835,7 @@ fix_mod(mrb_state *mrb, mrb_value x)
     mrb_float mod;
 
     flodivmod(mrb, (mrb_float)a, mrb_to_flo(mrb, y), 0, &mod);
-    return mrb_float_value(mod);
+    return mrb_float_value(mrb, mod);
   }
 }
 
@@ -856,8 +856,8 @@ fix_divmod(mrb_state *mrb, mrb_value x)
     mrb_int div, mod;
 
     if (mrb_fixnum(y) == 0) {
-      return mrb_assoc_new(mrb, mrb_float_value(str_to_mrb_float("inf")),
-        mrb_float_value(str_to_mrb_float("nan")));
+      return mrb_assoc_new(mrb, mrb_float_value(mrb, str_to_mrb_float("inf")),
+        mrb_float_value(mrb, str_to_mrb_float("nan")));
     }
     fixdivmod(mrb, mrb_fixnum(x), mrb_fixnum(y), &div, &mod);
     return mrb_assoc_new(mrb, mrb_fixnum_value(div), mrb_fixnum_value(mod));
@@ -867,8 +867,8 @@ fix_divmod(mrb_state *mrb, mrb_value x)
     mrb_value a, b;
 
     flodivmod(mrb, (mrb_float)mrb_fixnum(x), mrb_to_flo(mrb, y), &div, &mod);
-    a = mrb_float_value((mrb_int)div);
-    b = mrb_float_value(mod);
+    a = mrb_float_value(mrb, (mrb_int)div);
+    b = mrb_float_value(mrb, mod);
     return mrb_assoc_new(mrb, a, b);
   }
 }
@@ -1121,7 +1121,7 @@ fix_to_f(mrb_state *mrb, mrb_value num)
 
     val = (mrb_float)mrb_fixnum(num);
 
-    return mrb_float_value(val);
+    return mrb_float_value(mrb, val);
 }
 
 /*
@@ -1175,11 +1175,11 @@ mrb_fixnum_plus(mrb_state *mrb, mrb_value x, mrb_value y)
     c = a + b;
     if (((a < 0) ^ (b < 0)) == 0 && (a < 0) != (c < 0)) {
       /* integer overflow */
-      return mrb_float_value((mrb_float)a + (mrb_float)b);
+      return mrb_float_value(mrb, (mrb_float)a + (mrb_float)b);
     }
     return mrb_fixnum_value(c);
   }
-  return mrb_float_value((mrb_float)a + mrb_to_flo(mrb, y));
+  return mrb_float_value(mrb, (mrb_float)a + mrb_to_flo(mrb, y));
 }
 
 /* 15.2.8.3.1  */
@@ -1213,11 +1213,11 @@ mrb_fixnum_minus(mrb_state *mrb, mrb_value x, mrb_value y)
     c = a - b;
     if (((a < 0) ^ (b < 0)) != 0 && (a < 0) != (c < 0)) {
       /* integer overflow */
-      return mrb_float_value((mrb_float)a - (mrb_float)b);
+      return mrb_float_value(mrb, (mrb_float)a - (mrb_float)b);
     }
     return mrb_fixnum_value(c);
   }
-  return mrb_float_value((mrb_float)a - mrb_to_flo(mrb, y));
+  return mrb_float_value(mrb, (mrb_float)a - mrb_to_flo(mrb, y));
 }
 
 /* 15.2.8.3.2  */
@@ -1347,7 +1347,7 @@ flo_plus(mrb_state *mrb, mrb_value self)
   x = mrb_float(self);
   mrb_get_args(mrb, "f", &y);
 
-  return mrb_float_value(x + y);
+  return mrb_float_value(mrb, x + y);
 }
 /* ------------------------------------------------------------------------*/
 void
diff --git a/src/object.c b/src/object.c
index 09dfba41e..a2162f77f 100644
--- a/src/object.c
+++ b/src/object.c
@@ -571,13 +571,13 @@ mrb_Float(mrb_state *mrb, mrb_value val)
   }
   switch (mrb_type(val)) {
     case MRB_TT_FIXNUM:
-      return mrb_float_value((mrb_float)mrb_fixnum(val));
+      return mrb_float_value(mrb, (mrb_float)mrb_fixnum(val));
 
     case MRB_TT_FLOAT:
       return val;
 
     case MRB_TT_STRING:
-      return mrb_float_value(mrb_str_to_dbl(mrb, val, TRUE));
+      return mrb_float_value(mrb, mrb_str_to_dbl(mrb, val, TRUE));
 
     default:
       return mrb_convert_type(mrb, val, MRB_TT_FLOAT, "Float", "to_f");
diff --git a/src/string.c b/src/string.c
index 9bc178499..77f81ecc6 100644
--- a/src/string.c
+++ b/src/string.c
@@ -2222,7 +2222,7 @@ mrb_str_to_dbl(mrb_state *mrb, mrb_value str, int badcheck)
 static mrb_value
 mrb_str_to_f(mrb_state *mrb, mrb_value self)
 {
-  return mrb_float_value(mrb_str_to_dbl(mrb, self, 0/*Qfalse*/));
+  return mrb_float_value(mrb, mrb_str_to_dbl(mrb, self, 0/*Qfalse*/));
 }
 
 /* 15.2.10.5.40 */
diff --git a/src/vm.c b/src/vm.c
index 9d615e50f..38e3cd6ed 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -39,9 +39,11 @@ void abort(void);
 #define SET_SYM_VALUE(r,v) MRB_SET_VALUE(r, MRB_TT_SYMBOL, value.sym, (v))
 #define SET_OBJ_VALUE(r,v) MRB_SET_VALUE(r, (((struct RObject*)(v))->tt), value.p, (v))
 #ifdef MRB_NAN_BOXING
-#define SET_FLT_VALUE(r,v) r.f = (v)
+#define SET_FLT_VALUE(mrb,r,v) r.f = (v)
+#elif defined(MRB_WORD_BOXING)
+#define SET_FLT_VALUE(mrb,r,v) r = mrb_float_value(mrb, (v))
 #else
-#define SET_FLT_VALUE(r,v) MRB_SET_VALUE(r, MRB_TT_FLOAT, value.f, (v))
+#define SET_FLT_VALUE(mrb,r,v) MRB_SET_VALUE(r, MRB_TT_FLOAT, value.f, (v))
 #endif
 
 #define STACK_INIT_SIZE 128
@@ -1243,7 +1245,7 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
 
       L_RAISE:
         ci = mrb->c->ci;
-        mrb_obj_iv_ifnone(mrb, mrb->exc, mrb_intern2(mrb, "lastpc", 6), mrb_voidp_value(pc));
+        mrb_obj_iv_ifnone(mrb, mrb->exc, mrb_intern2(mrb, "lastpc", 6), mrb_voidp_value(mrb, pc));
         mrb_obj_iv_ifnone(mrb, mrb->exc, mrb_intern2(mrb, "ciidx", 5), mrb_fixnum_value(ci - mrb->c->cibase));
         eidx = ci->eidx;
         if (ci == mrb->c->cibase) {
@@ -1441,6 +1443,8 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
 #define attr_i value.i
 #ifdef MRB_NAN_BOXING
 #define attr_f f
+#elif defined(MRB_WORD_BOXING)
+#define attr_f value.fp->f
 #else
 #define attr_f value.f
 #endif
@@ -1464,27 +1468,45 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
           x = mrb_fixnum(regs_a[0]);
           y = mrb_fixnum(regs_a[1]);
           z = x + y;
+#ifdef MRB_WORD_BOXING
+          z = (z << MRB_FIXNUM_SHIFT) / (1 << MRB_FIXNUM_SHIFT);
+#endif
           if ((x < 0) != (z < 0) && ((x < 0) ^ (y < 0)) == 0) {
             /* integer overflow */
-            SET_FLT_VALUE(regs_a[0], (mrb_float)x + (mrb_float)y);
-          }
-          else {
-            regs_a[0].attr_i = z;
+            SET_FLT_VALUE(mrb, regs_a[0], (mrb_float)x + (mrb_float)y);
+            break;
           }
+          SET_INT_VALUE(regs[a], z);
         }
         break;
       case TYPES2(MRB_TT_FIXNUM,MRB_TT_FLOAT):
         {
           mrb_int x = mrb_fixnum(regs[a]);
           mrb_float y = mrb_float(regs[a+1]);
-          SET_FLT_VALUE(regs[a], (mrb_float)x + y);
+          SET_FLT_VALUE(mrb, regs[a], (mrb_float)x + y);
         }
         break;
       case TYPES2(MRB_TT_FLOAT,MRB_TT_FIXNUM):
+#ifdef MRB_WORD_BOXING
+        {
+          mrb_float x = mrb_float(regs[a]);
+          mrb_int y = mrb_fixnum(regs[a+1]);
+          SET_FLT_VALUE(mrb, regs[a], x + y);
+        }
+#else
         OP_MATH_BODY(+,attr_f,attr_i);
+#endif
         break;
       case TYPES2(MRB_TT_FLOAT,MRB_TT_FLOAT):
+#ifdef MRB_WORD_BOXING
+        {
+          mrb_float x = mrb_float(regs[a]);
+          mrb_float y = mrb_float(regs[a+1]);
+          SET_FLT_VALUE(mrb, regs[a], x + y);
+        }
+#else
         OP_MATH_BODY(+,attr_f,attr_f);
+#endif
         break;
       case TYPES2(MRB_TT_STRING,MRB_TT_STRING):
         regs[a] = mrb_str_plus(mrb, regs[a], regs[a+1]);
@@ -1509,9 +1531,12 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
           x = mrb_fixnum(regs[a]);
           y = mrb_fixnum(regs[a+1]);
           z = x - y;
+#ifdef MRB_WORD_BOXING
+          z = (z << MRB_FIXNUM_SHIFT) / (1 << MRB_FIXNUM_SHIFT);
+#endif
           if (((x < 0) ^ (y < 0)) != 0 && (x < 0) != (z < 0)) {
             /* integer overflow */
-            SET_FLT_VALUE(regs[a], (mrb_float)x - (mrb_float)y);
+            SET_FLT_VALUE(mrb, regs[a], (mrb_float)x - (mrb_float)y);
             break;
           }
           SET_INT_VALUE(regs[a], z);
@@ -1521,14 +1546,30 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
         {
           mrb_int x = mrb_fixnum(regs[a]);
           mrb_float y = mrb_float(regs[a+1]);
-          SET_FLT_VALUE(regs[a], (mrb_float)x - y);
+          SET_FLT_VALUE(mrb, regs[a], (mrb_float)x - y);
         }
         break;
       case TYPES2(MRB_TT_FLOAT,MRB_TT_FIXNUM):
+#ifdef MRB_WORD_BOXING
+        {
+          mrb_float x = mrb_float(regs[a]);
+          mrb_int y = mrb_fixnum(regs[a+1]);
+          SET_FLT_VALUE(mrb, regs[a], x - y);
+        }
+#else
         OP_MATH_BODY(-,attr_f,attr_i);
+#endif
         break;
       case TYPES2(MRB_TT_FLOAT,MRB_TT_FLOAT):
+#ifdef MRB_WORD_BOXING
+        {
+          mrb_float x = mrb_float(regs[a]);
+          mrb_float y = mrb_float(regs[a+1]);
+          SET_FLT_VALUE(mrb, regs[a], x - y);
+        }
+#else
         OP_MATH_BODY(-,attr_f,attr_f);
+#endif
         break;
       default:
         goto L_SEND;
@@ -1549,8 +1590,11 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
           x = mrb_fixnum(regs[a]);
           y = mrb_fixnum(regs[a+1]);
           z = x * y;
+#ifdef MRB_WORD_BOXING
+          z = (z << MRB_FIXNUM_SHIFT) / (1 << MRB_FIXNUM_SHIFT);
+#endif
           if (x != 0 && z/x != y) {
-            SET_FLT_VALUE(regs[a], (mrb_float)x * (mrb_float)y);
+            SET_FLT_VALUE(mrb, regs[a], (mrb_float)x * (mrb_float)y);
           }
           else {
             SET_INT_VALUE(regs[a], z);
@@ -1561,14 +1605,30 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
         {
           mrb_int x = mrb_fixnum(regs[a]);
           mrb_float y = mrb_float(regs[a+1]);
-          SET_FLT_VALUE(regs[a], (mrb_float)x * y);
+          SET_FLT_VALUE(mrb, regs[a], (mrb_float)x * y);
         }
         break;
       case TYPES2(MRB_TT_FLOAT,MRB_TT_FIXNUM):
+#ifdef MRB_WORD_BOXING
+        {
+          mrb_float x = mrb_float(regs[a]);
+          mrb_int y = mrb_fixnum(regs[a+1]);
+          SET_FLT_VALUE(mrb, regs[a], x * y);
+        }
+#else
         OP_MATH_BODY(*,attr_f,attr_i);
+#endif
         break;
       case TYPES2(MRB_TT_FLOAT,MRB_TT_FLOAT):
+#ifdef MRB_WORD_BOXING
+        {
+          mrb_float x = mrb_float(regs[a]);
+          mrb_float y = mrb_float(regs[a+1]);
+          SET_FLT_VALUE(mrb, regs[a], x * y);
+        }
+#else
         OP_MATH_BODY(*,attr_f,attr_f);
+#endif
         break;
       default:
         goto L_SEND;
@@ -1586,21 +1646,37 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
         {
           mrb_int x = mrb_fixnum(regs[a]);
           mrb_int y = mrb_fixnum(regs[a+1]);
-          SET_FLT_VALUE(regs[a], (mrb_float)x / (mrb_float)y);
+          SET_FLT_VALUE(mrb, regs[a], (mrb_float)x / (mrb_float)y);
         }
         break;
       case TYPES2(MRB_TT_FIXNUM,MRB_TT_FLOAT):
         {
           mrb_int x = mrb_fixnum(regs[a]);
           mrb_float y = mrb_float(regs[a+1]);
-          SET_FLT_VALUE(regs[a], (mrb_float)x / y);
+          SET_FLT_VALUE(mrb, regs[a], (mrb_float)x / y);
         }
         break;
       case TYPES2(MRB_TT_FLOAT,MRB_TT_FIXNUM):
+#ifdef MRB_WORD_BOXING
+        {
+          mrb_float x = mrb_float(regs[a]);
+          mrb_int y = mrb_fixnum(regs[a+1]);
+          SET_FLT_VALUE(mrb, regs[a], x / y);
+        }
+#else
         OP_MATH_BODY(/,attr_f,attr_i);
+#endif
         break;
       case TYPES2(MRB_TT_FLOAT,MRB_TT_FLOAT):
+#ifdef MRB_WORD_BOXING
+        {
+          mrb_float x = mrb_float(regs[a]);
+          mrb_float y = mrb_float(regs[a+1]);
+          SET_FLT_VALUE(mrb, regs[a], x / y);
+        }
+#else
         OP_MATH_BODY(/,attr_f,attr_f);
+#endif
         break;
       default:
         goto L_SEND;
@@ -1622,14 +1698,21 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
 
           if (((x < 0) ^ (y < 0)) == 0 && (x < 0) != (z < 0)) {
             /* integer overflow */
-            SET_FLT_VALUE(regs[a], (mrb_float)x + (mrb_float)y);
+            SET_FLT_VALUE(mrb, regs[a], (mrb_float)x + (mrb_float)y);
             break;
           }
           regs[a].attr_i = z;
         }
         break;
       case MRB_TT_FLOAT:
+#ifdef MRB_WORD_BOXING
+        {
+          mrb_float x = mrb_float(regs[a]);
+          SET_FLT_VALUE(mrb, regs[a], x + GETARG_C(i));
+        }
+#else
         regs[a].attr_f += GETARG_C(i);
+#endif
         break;
       default:
         SET_INT_VALUE(regs[a+1], GETARG_C(i));
@@ -1654,7 +1737,7 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
 
           if ((x < 0) != (z < 0) && ((x < 0) ^ (y < 0)) != 0) {
             /* integer overflow */
-            SET_FLT_VALUE(regs_a[0], (mrb_float)x - (mrb_float)y);
+            SET_FLT_VALUE(mrb, regs_a[0], (mrb_float)x - (mrb_float)y);
           }
           else {
             regs_a[0].attr_i = z;
@@ -1662,7 +1745,14 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
         }
         break;
       case MRB_TT_FLOAT:
+#ifdef MRB_WORD_BOXING
+        {
+          mrb_float x = mrb_float(regs[a]);
+          SET_FLT_VALUE(mrb, regs[a], x - GETARG_C(i));
+        }
+#else
         regs_a[0].attr_f -= GETARG_C(i);
+#endif
         break;
       default:
         SET_INT_VALUE(regs_a[1], GETARG_C(i));