diff options
-rw-r--r-- | ChangeLog | 5 | ||||
-rw-r--r-- | bignum.c | 21 |
2 files changed, 26 insertions, 0 deletions
@@ -1,3 +1,8 @@ +Mon Jul 29 00:11:49 2013 Tanaka Akira <akr@fsij.org> + + * bignum.c (bigdivrem): Specialized implementation added for + nx == 2 && ny == 2 + Sun Jul 28 20:28:41 2013 Masaki Matsushita <glass.saga@gmail.com> * io.c (io_getpartial): use rb_str_locktmp_ensure(). @@ -5399,6 +5399,27 @@ bigdivrem(VALUE x, VALUE y, volatile VALUE *divp, volatile VALUE *modp) if (divp) *divp = z; return Qnil; } + if (nx == 2 && ny == 2) { + BDIGIT_DBL x0 = xds[0] | BIGUP(xds[1]); + BDIGIT_DBL y0 = yds[0] | BIGUP(yds[1]); + BDIGIT_DBL q0 = x0 / y0; + BDIGIT_DBL r0 = x0 % y0; + if (divp) { + z = bignew(bdigit_roomof(sizeof(BDIGIT_DBL)), RBIGNUM_SIGN(x)==RBIGNUM_SIGN(y)); + zds = BDIGITS(z); + zds[0] = BIGLO(q0); + zds[1] = BIGLO(BIGDN(q0)); + *divp = z; + } + if (modp) { + z = bignew(bdigit_roomof(sizeof(BDIGIT_DBL)), RBIGNUM_SIGN(x)); + zds = BDIGITS(z); + zds[0] = BIGLO(r0); + zds[1] = BIGLO(BIGDN(r0)); + *modp = z; + } + return Qnil; + } if (BDIGIT_MSB(yds[ny-1]) == 0) { /* Make yds modifiable. */ |