diff options
author | Kent Boortz <kent@mysql.se> | 2000-08-02 18:48:06 +0200 |
---|---|---|
committer | Kent Boortz <kent@mysql.se> | 2000-08-02 18:48:06 +0200 |
commit | efe82bb8e93212508c8b292754422df81ef8fbc2 (patch) | |
tree | 6789e688820ffb0661381f240f10f765a8286025 /mpfr/mul_ui.c | |
parent | a54783120893faf758d85daee13c0a88c3296553 (diff) | |
download | gmp-efe82bb8e93212508c8b292754422df81ef8fbc2.tar.gz |
Experimental version of mpfr
Diffstat (limited to 'mpfr/mul_ui.c')
-rw-r--r-- | mpfr/mul_ui.c | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/mpfr/mul_ui.c b/mpfr/mul_ui.c new file mode 100644 index 000000000..db4c39a90 --- /dev/null +++ b/mpfr/mul_ui.c @@ -0,0 +1,84 @@ +/* mpfr_mul_ui -- multiply a floating-point number by a machine integer + +Copyright (C) 1999 PolKA project, Inria Lorraine and Loria + +This file is part of the MPFR Library. + +The MPFR Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Library General Public License as published by +the Free Software Foundation; either version 2 of the License, or (at your +option) any later version. + +The MPFR Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public +License for more details. + +You should have received a copy of the GNU Library General Public License +along with the MPFR Library; see the file COPYING.LIB. If not, write to +the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +MA 02111-1307, USA. */ + +#include <stdio.h> +#include "gmp.h" +#include "gmp-impl.h" +#include "longlong.h" +#include "mpfr.h" + +void +#if __STDC__ +mpfr_mul_ui(mpfr_ptr y, mpfr_srcptr x, unsigned long u, unsigned char RND_MODE) +#else +mpfr_mul_ui() + mpfr_ptr y; + mpfr_srcptr x; + unsigned long u; + unsigned char RND_MODE; +#endif +{ + mp_limb_t carry, *my, *old_my; unsigned long c; + unsigned long xsize, ysize, cnt, dif; + TMP_DECL(marker); + + TMP_MARK(marker); + my = MANT(y); + ysize = (PREC(y)-1)/BITS_PER_MP_LIMB + 1; + xsize = (PREC(x)-1)/BITS_PER_MP_LIMB + 1; + + if (ysize < xsize) { + old_my = my; + my = (mp_ptr) TMP_ALLOC (xsize * BYTES_PER_MP_LIMB); + dif=0; + } + else dif=ysize-xsize; + + carry = mpn_mul_1(my+dif, MANT(x), xsize, u); + MPN_ZERO(my, dif); + + /* WARNING: count_leading_zeros is undefined for carry=0 */ + if (carry) count_leading_zeros(cnt, carry); + else cnt=BITS_PER_MP_LIMB; + + c = mpfr_round_raw(my, my, PREC(x), (SIGN(x)<0), + PREC(y)-BITS_PER_MP_LIMB+cnt, RND_MODE); + + /* If cnt = 1111111111111 and c = 1 we shall get depressed */ + if (c && (carry == (((mp_limb_t)1) << (BITS_PER_MP_LIMB - cnt)) - 1)) + { + cnt--; + mpn_rshift(my, my, ysize, BITS_PER_MP_LIMB - cnt); + my[ysize - 1] |= ((mp_limb_t) 1) << (BITS_PER_MP_LIMB - 1); + } + else + { + /* Warning: mpn_rshift is undefined for shift=0 */ + if (cnt!=BITS_PER_MP_LIMB) + mpn_rshift(my, my, ysize, BITS_PER_MP_LIMB - cnt); + my[ysize - 1] |= (carry << cnt); + } + EXP(y) = EXP(x) + BITS_PER_MP_LIMB - cnt; + if (ysize < xsize) MPN_COPY(old_my, my, ysize); + /* set sign */ + if (SIGN(y) != SIGN(x)) CHANGE_SIGN(y); + TMP_FREE(marker); +} |