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author | akr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2013-06-15 14:52:02 +0000 |
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committer | akr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2013-06-15 14:52:02 +0000 |
commit | 392def5b71d74f6c1061a17fe858a601f17e1abb (patch) | |
tree | b681ec60c9672b61851904e901bc2e56b81a40ef | |
parent | 988c22ea72eb532d8e7b90cfc975d9d6b474f880 (diff) | |
download | ruby-392def5b71d74f6c1061a17fe858a601f17e1abb.tar.gz |
* bignum.c (bary_sub): New function.
(absint_numwords_generic): Use bary_sub.
(bigsub_core): Skip unnecessary copy.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41314 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
-rw-r--r-- | ChangeLog | 6 | ||||
-rw-r--r-- | bignum.c | 17 |
2 files changed, 22 insertions, 1 deletions
@@ -1,3 +1,9 @@ +Sat Jun 15 23:50:24 2013 Tanaka Akira <akr@fsij.org> + + * bignum.c (bary_sub): New function. + (absint_numwords_generic): Use bary_sub. + (bigsub_core): Skip unnecessary copy. + Sat Jun 15 22:05:30 2013 Tanaka Akira <akr@fsij.org> * bignum.c (bary_mul): New function. @@ -59,6 +59,7 @@ static BDIGIT bdigs_small_lshift(BDIGIT *zds, BDIGIT *xds, long n, int shift); static void bdigs_small_rshift(BDIGIT *zds, BDIGIT *xds, long n, int shift, int sign_bit); static void bary_unpack(BDIGIT *bdigits, size_t num_bdigits, const void *words, size_t numwords, size_t wordsize, size_t nails, int flags); static void bary_mul(BDIGIT *zds, size_t zl, BDIGIT *xds, size_t xl, BDIGIT *yds, size_t yl); +static void bary_sub(BDIGIT *zds, size_t zn, BDIGIT *xds, size_t xn, BDIGIT *yds, size_t yn); #define BIGNUM_DEBUG 0 #if BIGNUM_DEBUG @@ -599,6 +600,7 @@ absint_numwords_generic(size_t numbytes, int nlz_bits_in_msbyte, size_t word_num BDIGIT numbytes_bary[bdigit_roomof(sizeof(numbytes))]; BDIGIT char_bit[1] = { CHAR_BIT }; BDIGIT val_numbits_bary[bdigit_roomof(sizeof(numbytes) + 1)]; + BDIGIT nlz_bits_in_msbyte_bary[1] = { nlz_bits_in_msbyte }; VALUE v; /* @@ -611,15 +613,17 @@ absint_numwords_generic(size_t numbytes, int nlz_bits_in_msbyte, size_t word_num bary_unpack(BARY_ARGS(numbytes_bary), &numbytes, 1, sizeof(numbytes), 0, INTEGER_PACK_NATIVE_BYTE_ORDER); bary_mul(BARY_ARGS(val_numbits_bary), BARY_ARGS(numbytes_bary), BARY_ARGS(char_bit)); + if (nlz_bits_in_msbyte) + bary_sub(BARY_ARGS(val_numbits_bary), BARY_ARGS(val_numbits_bary), BARY_ARGS(nlz_bits_in_msbyte_bary)); v = rb_integer_unpack(val_numbits_bary, numberof(val_numbits_bary), sizeof(BDIGIT), 0, INTEGER_PACK_LSWORD_FIRST|INTEGER_PACK_NATIVE_BYTE_ORDER); val_numbits = SIZET2NUM(numbytes); val_numbits = rb_funcall(val_numbits, '*', 1, LONG2FIX(CHAR_BIT)); - assert(rb_equal(val_numbits, v)); if (nlz_bits_in_msbyte) val_numbits = rb_funcall(val_numbits, '-', 1, LONG2FIX(nlz_bits_in_msbyte)); + assert(rb_equal(val_numbits, v)); word_numbits_v = SIZET2NUM(word_numbits); div_mod = rb_funcall(val_numbits, rb_intern("divmod"), 1, word_numbits_v); div = RARRAY_AREF(div_mod, 0); @@ -2850,6 +2854,8 @@ bigsub_core(BDIGIT *xds, long xn, BDIGIT *yds, long yn, BDIGIT *zds, long zn) zds[i++] = BIGLO(num); num = BIGDN(num); } + if (xds == zds && xn == zn) + return; while (i < xn) { zds[i] = xds[i]; i++; @@ -2860,6 +2866,15 @@ bigsub_core(BDIGIT *xds, long xn, BDIGIT *yds, long yn, BDIGIT *zds, long zn) } } +static void +bary_sub(BDIGIT *zds, size_t zn, BDIGIT *xds, size_t xn, BDIGIT *yds, size_t yn) +{ + assert(yn <= xn); + assert(xn <= zn); + + bigsub_core(xds, xn, yds, yn, zds, zn); +} + static VALUE bigsub(VALUE x, VALUE y) { |