Change default boxing scheme from `MRB_NO_BOXING`.

On 64bit platforms: `MRB_NAN_BOXING`
On 32bit platforms: `MRB_WORD_BOXING`
On debugging: `MRB_NO_BOXING`

include/mrbconf.h

@@ -53,12 +53,41 @@
 # endif
 #endif
 
+/* define on big endian machines; used by MRB_NAN_BOXING, etc. */
+#ifndef MRB_ENDIAN_BIG
+# if (defined(BYTE_ORDER) && defined(BIG_ENDIAN) && BYTE_ORDER == BIG_ENDIAN) || \
+     (defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+#  define MRB_ENDIAN_BIG
+# endif
+#endif
+
+/* represent mrb_value in boxed double; conflict with MRB_USE_FLOAT and MRB_WITHOUT_FLOAT */
+//#define MRB_NAN_BOXING
+
+/* represent mrb_value as a word (natural unit of data for the processor) */
+//#define MRB_WORD_BOXING
+
+/* with MRB_WORD_BOXING, embed float values in mrb_value (dropping 2 bit precision) */
+//#define MRB_WBOX_FLOAT_INLINE
+
+/* represent mrb_value as a struct; occupies 2 words */
+//#define MRB_NO_BOXING
+
+/* if no specific boxing type is chosen */
+#if !defined(MRB_NAN_BOXING) && !defined(MRB_WORD_BOXING) && !defined(MRB_NO_BOXING)
+# if defined(MRB_64BIT) && !defined(MRB_INT64)
+#  define MRB_NAN_BOXING
+# else
+#  define MRB_WORD_BOXING
+# endif
+#endif
+
 /* add -DMRB_INT32 to use 32bit integer for mrb_int; conflict with MRB_INT64;
    Default for 32-bit CPU mode. */
 //#define MRB_INT32
 
 /* add -DMRB_INT64 to use 64bit integer for mrb_int; conflict with MRB_INT32;
-   Default for 64-bit CPU mode. */
+   Default for 64-bit CPU mode (unless using MRB_NAN_BOXING). */
 //#define MRB_INT64
 
 /* if no specific integer type is chosen */
@@ -72,20 +101,6 @@
 # endif
 #endif
 
-/* define on big endian machines; used by MRB_NAN_BOXING, etc. */
-#ifndef MRB_ENDIAN_BIG
-# if (defined(BYTE_ORDER) && defined(BIG_ENDIAN) && BYTE_ORDER == BIG_ENDIAN) || \
-     (defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
-#  define MRB_ENDIAN_BIG
-# endif
-#endif
-
-/* represent mrb_value in boxed double; conflict with MRB_USE_FLOAT and MRB_WITHOUT_FLOAT */
-//#define MRB_NAN_BOXING
-
-/* represent mrb_value as a word (natural unit of data for the processor) */
-//#define MRB_WORD_BOXING
-
 /* string class to handle UTF-8 encoding */
 //#define MRB_UTF8_STRING
 

target/boxing.rb

@@ -5,6 +5,9 @@ end
 MRuby::Build.new('no_boxing') do |conf|
   toolchain :gcc
 
+  conf.compilers.each do |c|
+    c.defines += %w(MRB_NO_BOXING)
+  end
   conf.gembox 'default'
   conf.enable_test
 end

target/host-debug.rb

@@ -14,7 +14,7 @@ MRuby::Build.new('host-debug') do |conf|
   conf.gembox 'full-core'
 
   # C compiler settings
-  conf.cc.defines = %w(MRB_ENABLE_DEBUG_HOOK)
+  conf.cc.defines = %w(MRB_ENABLE_DEBUG_HOOK MRB_NO_BOXING)
 
   # Generate mruby debugger command (require mruby-eval)
   conf.gem :core => "mruby-bin-debugger"