Adding `MRB_WORDBOX_NO_FLOAT_TRUNCATE` to the build configuration in 32-bit CPU mode had a double definition.
```console
% cat myconf.rb
MRuby::Build.new do
toolchain "clang"
defines << "MRB_WORDBOX_NO_FLOAT_TRUNCATE"
cc.flags << "-m32"
linker.flags << "-m32"
enable_debug
end
% rake CONFIG=myconf.rb
CPP src/array.c -> build/host/src/array.pi
In file included from /var/tmp/mruby/src/array.c:7:
In file included from /var/tmp/mruby/include/mruby.h:115:
In file included from /var/tmp/mruby/include/mruby/value.h:203:
/var/tmp/mruby/include/mruby/boxing_word.h:11:10: warning:
'MRB_WORDBOX_NO_FLOAT_TRUNCATE' macro redefined [-Wmacro-redefined]
# define MRB_WORDBOX_NO_FLOAT_TRUNCATE
^
<command line>:3:9: note: previous definition is here
#define MRB_WORDBOX_NO_FLOAT_TRUNCATE 1
^
1 warning generated.
...SNIP...
```
Embedding reduce memory consumption, sacrificing precision. It clips least
significant 2 bits from `mrb_float`, so if you need to keep float precision,
define `MRB_USE_FLOAT_FULL_PRECISION`.
`MRB_WORD_BOXING` and `MRB_INT64`:
`mrb_float` (`double`) is embedded in `mrb_value` clipped last 2 bits.
`MRB_WORD_BOXING` and `MRB_INT64` and `MRB_USE_FLOAT_FULL_PRECISION`:
`mrb_float` is allocated in the heaps wrapped by `struct RFloat`.
`MRB_WORD_BOXING` and `MRB_INT32` and `MRB_USE_FLOAT32`:
`mrb_float` (`float`) is embedded in `mrb_value` clipped last 2 bits.
In addition, to reserve bit space in the `mrb_value`, maximum inline
symbol length become 4 (instead of 5) in the configuration.
`MRB_WORD_BOXING` and `MRB_INT32`:
Assume `MRB_USE_FLOAT_FULL_PRECISION` and allocate Float values in heap.
- Integrate `Fixnum` and `Integer`
- Remove `Integral`
- `int / int -> int`
- Replace `mrb_fixnum()` to `mrb_int()`
- Replace `mrb_fixnum_value()` to `mrb_int_value()`.
- Use `mrb_integer_p()` instead of `mrb_fixnum_p()`
- `MRB_WITHOUT_FLOAT` => `MRB_NO_FLOAT`
- `MRB_USE_FLOAT` => `MRB_USE_FLOAT32`
The former is to use `USE_XXX` naming convention. The latter is to make
sure `float` is 32bit float and not floating point number in general.
Changes:
- `pool format is completely replaced
- supported types: `STR`, `INT32`, `INT64`, `FLOAT`
- `FLOAT` may be replaced by binary representation in the future
- insert `NUL` after string literals in `mrb` files
- `irep->pool` no longer store values in `mrb_value`
- instead it stores in `mrb_pool_value`
- less allocation
- `mrb_irep` can be stored in ROM
Previously, if `MRB_NAN_BOXING` is defined, for example,
`mrb_cptr_value()` could not keep an odd address.
If it is `MRB_32BIT`, it can be embedded in `NaN` as it is.
If it is `MRB_64BIT`, some operations are shared with `MRB_WORD_BOXING`.
In this case, the MRB_API function `mrb_nan_boxing_cptr_value()` is
defined.
The default implementations of type predicate macros use `mrb_type`.
But `mrb_type` with `MRB_WORD_BOXING` isn't very efficient, so the new
implementations avoid `mrb_type`.
The changes at b2c3d88f were inappropriate because the memory layout of bit
fields are implementation defined. Therefor, I fixed it not to use bit
fields.
The default implementation of `mrb_immediate_p` uses `mrb_type`. However,
in `MRB_WORD_BOXING`, `mrb_type` has many branches and is inefficient, so
provide an implementation that does not use `mrb_type`.
Yukihiro "Matz" Matsumoto