diff options
| -rw-r--r-- | include/mruby/numeric.h | 35 | ||||
| -rw-r--r-- | src/numeric.c | 16 | ||||
| -rw-r--r-- | src/vm.c | 22 |
3 files changed, 45 insertions, 28 deletions
diff --git a/include/mruby/numeric.h b/include/mruby/numeric.h index b16c299a4..e4086487e 100644 --- a/include/mruby/numeric.h +++ b/include/mruby/numeric.h @@ -62,6 +62,12 @@ mrb_int_sub_overflow(mrb_int minuend, mrb_int subtrahend, mrb_int *difference) return __builtin_sub_overflow(minuend, subtrahend, difference) || WBCHK(*difference); } +static inline mrb_bool +mrb_int_mul_overflow(mrb_int multiplier, mrb_int multiplicand, mrb_int *product) +{ + return __builtin_mul_overflow(multiplier, multiplicand, product) || WBCHK(*product); +} + #undef WBCHK #else @@ -92,6 +98,35 @@ mrb_int_sub_overflow(mrb_int minuend, mrb_int subtrahend, mrb_int *difference) return !!(((x ^ z) & (~y ^ z)) & MRB_INT_OVERFLOW_MASK); } +static inline mrb_bool +mrb_int_mul_overflow(mrb_int multiplier, mrb_int multiplicand, mrb_int *product) +{ +#if MRB_INT_BIT == 32 + int64_t n = (int64_t)multiplier * multiplicand; + *product = (mrb_int)n; + return !FIXABLE(n); +#else + if (multiplier > 0) { + if (multiplicand > 0) { + if (multiplier > MRB_INT_MAX / multiplicand) return TRUE; + } + else { + if (multiplicand < MRB_INT_MAX / multiplier) return TRUE; + } + } + else { + if (multiplicand > 0) { + if (multiplier < MRB_INT_MAX / multiplicand) return TRUE; + } + else { + if (multiplier != 0 && multiplicand < MRB_INT_MAX / multiplier) return TRUE; + } + } + *product = multiplier * multiplicand; + return FALSE; +#endif +} + #undef MRB_INT_OVERFLOW_MASK #undef mrb_uint #undef MRB_UINT_MAKE diff --git a/src/numeric.c b/src/numeric.c index 7b49b29f7..85847284e 100644 --- a/src/numeric.c +++ b/src/numeric.c @@ -541,10 +541,6 @@ int_to_i(mrb_state *mrb, mrb_value num) return num; } -/*tests if N*N would overflow*/ -#define SQRT_INT_MAX ((mrb_int)1<<((MRB_INT_BIT-1-MRB_FIXNUM_SHIFT)/2)) -#define FIT_SQRT_INT(n) (((n)<SQRT_INT_MAX)&&((n)>=-SQRT_INT_MAX)) - mrb_value mrb_fixnum_mul(mrb_state *mrb, mrb_value x, mrb_value y) { @@ -552,18 +548,14 @@ mrb_fixnum_mul(mrb_state *mrb, mrb_value x, mrb_value y) a = mrb_fixnum(x); if (mrb_fixnum_p(y)) { - mrb_float c; - mrb_int b; + mrb_int b, c; if (a == 0) return x; b = mrb_fixnum(y); - if (FIT_SQRT_INT(a) && FIT_SQRT_INT(b)) - return mrb_fixnum_value(a*b); - c = a * b; - if ((a != 0 && c/a != b) || !FIXABLE(c)) { - return mrb_float_value(mrb, (mrb_float)a*(mrb_float)b); + if (mrb_int_mul_overflow(a, b, &c)) { + return mrb_float_value(mrb, (mrb_float)a * (mrb_float)b); } - return mrb_fixnum_value((mrb_int)c); + return mrb_fixnum_value(c); } return mrb_float_value(mrb, (mrb_float)a * mrb_to_flo(mrb, y)); } @@ -1862,25 +1862,15 @@ RETRY_TRY_BLOCK: switch (TYPES2(mrb_type(regs[a]),mrb_type(regs[a+1]))) { case TYPES2(MRB_TT_FIXNUM,MRB_TT_FIXNUM): { - mrb_value z; - - z = mrb_fixnum_mul(mrb, regs[a], regs[a+1]); + mrb_int x, y, z; - switch (mrb_type(z)) { - case MRB_TT_FIXNUM: - { - SET_INT_VALUE(regs[a], mrb_fixnum(z)); - } - break; - case MRB_TT_FLOAT: - { - SET_FLOAT_VALUE(mrb, regs[a], mrb_float(z)); - } - break; - default: - /* cannot happen */ + x = mrb_fixnum(regs[a]); + y = mrb_fixnum(regs[a+1]); + if (mrb_int_mul_overflow(x, y, &z)) { + SET_FLOAT_VALUE(mrb, regs[a], (mrb_float)x * (mrb_float)y); break; } + SET_INT_VALUE(regs[a], z); } break; case TYPES2(MRB_TT_FIXNUM,MRB_TT_FLOAT): |