diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/mruby/numeric.h | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/include/mruby/numeric.h b/include/mruby/numeric.h index 17291c2f2..fe4f3b264 100644 --- a/include/mruby/numeric.h +++ b/include/mruby/numeric.h @@ -25,6 +25,41 @@ mrb_value mrb_fixnum_mul(mrb_state *mrb, mrb_value x, mrb_value y); mrb_value mrb_num_div(mrb_state *mrb, mrb_value x, mrb_value y); mrb_float mrb_to_flo(mrb_state *mrb, mrb_value x); +#define MRB_UINT_MAKE2(n) uint ## n ## _t +#define MRB_UINT_MAKE(n) MRB_UINT_MAKE2(n) +#define mrb_uint MRB_UINT_MAKE(MRB_INT_BIT) + +#ifdef MRB_WORD_BOXING +# define MRB_INT_OVERFLOW_MASK ((mrb_uint)1 << (MRB_INT_BIT - 1 - MRB_FIXNUM_SHIFT)) +#else +# define MRB_INT_OVERFLOW_MASK ((mrb_uint)1 << (MRB_INT_BIT - 1)) +#endif + +static inline mrb_bool +mrb_int_add_overflow(mrb_int augend, mrb_int addend, mrb_int *sum) +{ + mrb_uint x = (mrb_uint)augend; + mrb_uint y = (mrb_uint)addend; + mrb_uint z = (mrb_uint)(x + y); + *sum = (mrb_int)z; + return !!(((x ^ z) & (y ^ z)) & MRB_INT_OVERFLOW_MASK); +} + +static inline mrb_bool +mrb_int_sub_overflow(mrb_int minuend, mrb_int subtrahend, mrb_int *difference) +{ + mrb_uint x = (mrb_uint)minuend; + mrb_uint y = (mrb_uint)subtrahend; + mrb_uint z = (mrb_uint)(x - y); + *difference = (mrb_int)z; + return !!(((x ^ z) & (~y ^ z)) & MRB_INT_OVERFLOW_MASK); +} + +#undef MRB_INT_OVERFLOW_MASK +#undef mrb_uint +#undef MRB_UINT_MAKE +#undef MRB_UINT_MAKE2 + #if defined(__cplusplus) } /* extern "C" { */ #endif |