diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | numeric.c | 12 |
2 files changed, 11 insertions, 6 deletions
@@ -1,3 +1,8 @@ +Sat Jul 14 02:27:43 2007 Yukihiro Matsumoto <matz@ruby-lang.org> + + * numeric.c (int_pow): overflow detection using FIT_SQRT_LONG(). + [ruby-dev:31215] + Sat Jul 14 02:05:53 2007 Yukihiro Matsumoto <matz@ruby-lang.org> * insns.def (opt_div): LONG2FIX() may not work for corner cases, @@ -2046,6 +2046,10 @@ fix_minus(VALUE x, VALUE y) * result. */ +#define SQRT_LONG_MAX ((SIGNED_VALUE)1<<((SIZEOF_VALUE*CHAR_BIT-1)/2)) +/*tests if N*N would overflow*/ +#define FIT_SQRT_LONG(n) (((n)<SQRT_LONG_MAX)&&((n)>=-SQRT_LONG_MAX)) + static VALUE fix_mul(VALUE x, VALUE y) { @@ -2070,9 +2074,6 @@ fix_mul(VALUE x, VALUE y) if (FIXABLE(d)) return LONG2FIX(d); return rb_ll2inum(d); #else -# define SQRT_LONG_MAX ((SIGNED_VALUE)1<<((SIZEOF_VALUE*CHAR_BIT-1)/2)) - /*tests if N*N would overflow*/ -# define FIT_SQRT_LONG(n) (((n)<SQRT_LONG_MAX)&&((n)>=-SQRT_LONG_MAX)) if (FIT_SQRT_LONG(a) && FIT_SQRT_LONG(b)) return LONG2FIX(a*b); c = a * b; @@ -2288,15 +2289,14 @@ int_pow(long x, unsigned long y) y &= ~1; do { while (y % 2 == 0) { - long x2 = x * x; - if (x2 < x || !POSFIXABLE(x2)) { + if (!FIT_SQRT_LONG(x)) { VALUE v; bignum: v = rb_big_pow(rb_int2big(x), LONG2NUM(y)); if (z != 1) v = rb_big_mul(rb_int2big(neg ? -z : z), v); return v; } - x = x2; + x = x * x; y >>= 1; } { |