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* bignum.c (rb_big_pow): Don't need to multiply SIZEOF_BDIGITS.

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Use nlz instead of bitlength_bdigit.
  (bitlength_bdigit): Removed.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41079 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
akr 2013-06-04 23:15:30 +00:00
parent 4eabe8193a
commit 14ec81b0a2
2 changed files with 8 additions and 20 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
Wed Jun 5 08:13:37 2013 Tanaka Akira <akr@fsij.org>
* bignum.c (rb_big_pow): Don't need to multiply SIZEOF_BDIGITS.
Use nlz instead of bitlength_bdigit.
(bitlength_bdigit): Removed.
Wed Jun 5 07:14:18 2013 Tadayoshi Funaba <tadf@dotrb.org> Wed Jun 5 07:14:18 2013 Tadayoshi Funaba <tadf@dotrb.org>
* ext/date/date_core.c (d_lite_cmp, d_lite_equal): simplified. * ext/date/date_core.c (d_lite_cmp, d_lite_equal): simplified.

22
bignum.c
View File

@ -3178,24 +3178,6 @@ bigsqr(VALUE x)
return bigtrunc(bigmul0(x, x)); return bigtrunc(bigmul0(x, x));
} }
static int
bitlength_bdigit(BDIGIT v)
{
if (v == 0)
return 0;
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
#if 2 < SIZEOF_BDIGITS
v |= v >> 16;
#endif
v++;
if (v == 0)
return SIZEOF_BDIGITS*CHAR_BIT;
return ffs(v)-1; /* assumption: sizeof(BDIGIT) <= sizeof(int) */
}
/* /*
* call-seq: * call-seq:
* big ** exponent -> numeric * big ** exponent -> numeric
@ -3236,8 +3218,8 @@ rb_big_pow(VALUE x, VALUE y)
else { else {
VALUE z = 0; VALUE z = 0;
SIGNED_VALUE mask; SIGNED_VALUE mask;
const long xlen = RBIGNUM_LEN(x) - 1; const long xlen = RBIGNUM_LEN(x);
const long xbits = bitlength_bdigit(RBIGNUM_DIGITS(x)[xlen]) + SIZEOF_BDIGITS*BITSPERDIG*xlen; const long xbits = BITSPERDIG*xlen - nlz(RBIGNUM_DIGITS(x)[xlen-1]);
const long BIGLEN_LIMIT = BITSPERDIG*1024*1024; const long BIGLEN_LIMIT = BITSPERDIG*1024*1024;
if ((xbits > BIGLEN_LIMIT) || (xbits * yy > BIGLEN_LIMIT)) { if ((xbits > BIGLEN_LIMIT) || (xbits * yy > BIGLEN_LIMIT)) {