diff options
Diffstat (limited to 'bignum.c')
| -rw-r--r-- | bignum.c | 29 |
1 files changed, 20 insertions, 9 deletions
@@ -89,6 +89,9 @@ static VALUE big_three = Qnil; #define BARY_DIVMOD(q, r, x, y) bary_divmod(BARY_ARGS(q), BARY_ARGS(r), BARY_ARGS(x), BARY_ARGS(y)) #define BARY_ZERO_P(x) bary_zero_p(BARY_ARGS(x)) +#define RBIGNUM_SET_NEGATIVE_SIGN(b) RBIGNUM_SET_SIGN(b, 0) +#define RBIGNUM_SET_POSITIVE_SIGN(b) RBIGNUM_SET_SIGN(b, 1) + static int nlz(BDIGIT x); static BDIGIT bary_small_lshift(BDIGIT *zds, BDIGIT *xds, long n, int shift); static void bary_small_rshift(BDIGIT *zds, BDIGIT *xds, long n, int shift, int sign_bit); @@ -3035,16 +3038,24 @@ static VALUE rb_big_neg(VALUE x) { VALUE z = rb_big_clone(x); - BDIGIT *ds; - long i; + BDIGIT *ds = BDIGITS(z); + long n = RBIGNUM_LEN(z); - if (!RBIGNUM_SIGN(x)) get2comp(z); - ds = BDIGITS(z); - i = RBIGNUM_LEN(x); - if (!i) return INT2FIX(~(SIGNED_VALUE)0); - bary_neg(ds, i); - RBIGNUM_SET_SIGN(z, !RBIGNUM_SIGN(z)); - if (RBIGNUM_SIGN(x)) get2comp(z); + if (!n) return INT2FIX(-1); + + if (RBIGNUM_POSITIVE_P(z)) { + if (bary_plus_one(ds, n)) { + big_extend_carry(z); + } + RBIGNUM_SET_NEGATIVE_SIGN(z); + } + else { + bary_neg(ds, n); + if (bary_plus_one(ds, n)) + return INT2FIX(-1); + bary_neg(ds, n); + RBIGNUM_SET_POSITIVE_SIGN(z); + } return bignorm(z); } |