diff options
| -rw-r--r-- | include/mruby/numeric.h | 10 | ||||
| -rw-r--r-- | src/numeric.c | 4 | ||||
| -rw-r--r-- | src/vm.c | 12 |
3 files changed, 14 insertions, 12 deletions
diff --git a/include/mruby/numeric.h b/include/mruby/numeric.h index 35be32a01..fe4f3b264 100644 --- a/include/mruby/numeric.h +++ b/include/mruby/numeric.h @@ -45,6 +45,16 @@ mrb_int_add_overflow(mrb_int augend, mrb_int addend, mrb_int *sum) 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 diff --git a/src/numeric.c b/src/numeric.c index 8ea71ada6..7b025c34d 100644 --- a/src/numeric.c +++ b/src/numeric.c @@ -1145,9 +1145,7 @@ mrb_fixnum_minus(mrb_state *mrb, mrb_value x, mrb_value y) mrb_int b, c; b = mrb_fixnum(y); - c = a - b; - if (((a < 0) ^ (b < 0)) != 0 && (a < 0) != (c < 0)) { - /* integer overflow */ + if (mrb_int_sub_overflow(a, b, &c)) { return mrb_float_value(mrb, (mrb_float)a - (mrb_float)b); } return mrb_fixnum_value(c); @@ -1669,12 +1669,7 @@ RETRY_TRY_BLOCK: 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 */ + if (mrb_int_sub_overflow(x, y, &z)) { SET_FLT_VALUE(mrb, regs[a], (mrb_float)x - (mrb_float)y); break; } @@ -1876,10 +1871,9 @@ RETRY_TRY_BLOCK: { mrb_int x = regs_a[0].attr_i; mrb_int y = GETARG_C(i); - mrb_int z = x - y; + mrb_int z; - if ((x < 0) != (z < 0) && ((x < 0) ^ (y < 0)) != 0) { - /* integer overflow */ + if (mrb_int_sub_overflow(x, y, &z)) { SET_FLT_VALUE(mrb, regs_a[0], (mrb_float)x - (mrb_float)y); } else { |