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* bignum.c (absint_numwords_small): New function.

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(absint_numwords_generic): Use absint_numwords_small if possible.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41201 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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akr 2013-06-09 20:39:05 +00:00
parent 79042beece
commit 192085bad3
2 changed files with 30 additions and 2 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
Mon Jun 10 05:38:23 2013 Tanaka Akira <akr@fsij.org>
* bignum.c (absint_numwords_small): New function.
(absint_numwords_generic): Use absint_numwords_small if possible.
Mon Jun 10 01:07:57 2013 Tanaka Akira <akr@fsij.org> Mon Jun 10 01:07:57 2013 Tanaka Akira <akr@fsij.org>
* bignum.c (absint_numwords_bytes): New function. * bignum.c (absint_numwords_bytes): New function.

27
bignum.c
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@ -555,7 +555,7 @@ absint_numwords_bytes(size_t numbytes, int nlz_bits_in_msbyte, size_t word_numbi
} }
else { else {
s = q - 1; s = q - 1;
t = word_numbits + r * CHAR_BIT - nlz_bits_in_msbyte; t = word_numbits - nlz_bits_in_msbyte + r * CHAR_BIT;
} }
div = s + t / word_numbits; div = s + t / word_numbits;
mod = t % word_numbits; mod = t % word_numbits;
@ -565,6 +565,20 @@ absint_numwords_bytes(size_t numbytes, int nlz_bits_in_msbyte, size_t word_numbi
return numwords; return numwords;
} }
size_t
absint_numwords_small(size_t numbytes, int nlz_bits_in_msbyte, size_t word_numbits, size_t *nlz_bits_ret)
{
size_t val_numbits = numbytes * CHAR_BIT - nlz_bits_in_msbyte;
size_t div = val_numbits / word_numbits;
size_t mod = val_numbits % word_numbits;
size_t numwords;
size_t nlz_bits;
numwords = mod == 0 ? div : div + 1;
nlz_bits = mod == 0 ? 0 : word_numbits - mod;
*nlz_bits_ret = nlz_bits;
return numwords;
}
size_t size_t
absint_numwords_generic(size_t numbytes, int nlz_bits_in_msbyte, size_t word_numbits, size_t *nlz_bits_ret) absint_numwords_generic(size_t numbytes, int nlz_bits_in_msbyte, size_t word_numbits, size_t *nlz_bits_ret)
{ {
@ -634,7 +648,16 @@ rb_absint_numwords(VALUE val, size_t word_numbits, size_t *nlz_bits_ret)
numbytes = rb_absint_size(val, &nlz_bits_in_msbyte); numbytes = rb_absint_size(val, &nlz_bits_in_msbyte);
if (word_numbits % CHAR_BIT == 0) { if (numbytes <= SIZE_MAX / CHAR_BIT) {
numwords = absint_numwords_small(numbytes, nlz_bits_in_msbyte, word_numbits, &nlz_bits);
#if 0
size_t numwords0, nlz_bits0;
numwords0 = absint_numwords_generic(numbytes, nlz_bits_in_msbyte, word_numbits, &nlz_bits0);
assert(numwords0 == numwords);
assert(nlz_bits0 == nlz_bits);
#endif
}
else if (word_numbits % CHAR_BIT == 0) {
numwords = absint_numwords_bytes(numbytes, nlz_bits_in_msbyte, word_numbits, &nlz_bits); numwords = absint_numwords_bytes(numbytes, nlz_bits_in_msbyte, word_numbits, &nlz_bits);
#if 0 #if 0
size_t numwords0, nlz_bits0; size_t numwords0, nlz_bits0;