OpenXM_contrib/gmp/mpn/generic/scan0.c - diff

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version 1.1.1.2, 2000/09/09 14:12:27

version 1.1.1.3, 2003/08/25 16:06:20

Line 1

/* mpn_scan0 -- Scan from a given bit position for the next clear bit.

This file is part of the GNU MP Library.

Line 28 MA 02111-1307, USA. */

2. Bit index should be 'unsigned'?

Argument constraints:

1. U must sooner ot later have a limb with a clear bit.

1. U must sooner or later have a limb with a clear bit.

unsigned long int

#if __STDC__

mpn_scan0 (register mp_srcptr up,

#else

mpn_scan0 (up, starting_bit)

#endif

{

mp_size_t starting_word;

mp_limb_t alimb;

Line 47 mpn_scan0 (up, starting_bit)

Line 41 mpn_scan0 (up, starting_bit)

mp_srcptr p;

/* Start at the word implied by STARTING_BIT. */

starting_word = starting_bit / BITS_PER_MP_LIMB;

starting_word = starting_bit / GMP_NUMB_BITS;

p = up + starting_word;

alimb = ~*p++;

alimb = *p++ ^ GMP_NUMB_MASK;

/* Mask off any bits before STARTING_BIT in the first limb. */

alimb &= - (mp_limb_t) 1 << (starting_bit % BITS_PER_MP_LIMB);

alimb &= - (mp_limb_t) 1 << (starting_bit % GMP_NUMB_BITS);

while (alimb == 0)

alimb = ~*p++;

alimb = *p++ ^ GMP_NUMB_MASK;

count_leading_zeros (cnt, alimb & -alimb);

count_trailing_zeros (cnt, alimb);

return (p - up) * BITS_PER_MP_LIMB - 1 - cnt;

return (p - up - 1) * GMP_NUMB_BITS + cnt;

}