diff options
author | tege <tege@gmplib.org> | 2002-04-20 16:42:23 +0200 |
---|---|---|
committer | tege <tege@gmplib.org> | 2002-04-20 16:42:23 +0200 |
commit | 3c7d00eb181e32917f7e8aac2d94f0ffde56056b (patch) | |
tree | 31732a62b53c3e1dfcc3afcabbc5e26f25d646c2 /mpz/fdiv_qr_ui.c | |
parent | 145ab235c286e4cacc64909886cbec3b217ce13b (diff) | |
download | gmp-3c7d00eb181e32917f7e8aac2d94f0ffde56056b.tar.gz |
Nailify.
Diffstat (limited to 'mpz/fdiv_qr_ui.c')
-rw-r--r-- | mpz/fdiv_qr_ui.c | 94 |
1 files changed, 71 insertions, 23 deletions
diff --git a/mpz/fdiv_qr_ui.c b/mpz/fdiv_qr_ui.c index 7d26ec6de..2ff0f27e1 100644 --- a/mpz/fdiv_qr_ui.c +++ b/mpz/fdiv_qr_ui.c @@ -26,36 +26,84 @@ MA 02111-1307, USA. */ unsigned long int mpz_fdiv_qr_ui (mpz_ptr quot, mpz_ptr rem, mpz_srcptr dividend, unsigned long int divisor) { - mp_size_t dividend_size; - mp_size_t size; - mp_ptr quot_ptr; - mp_limb_t remainder_limb; + mp_size_t ns, nn, qn; + mp_ptr np, qp; + mp_limb_t rl; if (divisor == 0) DIVIDE_BY_ZERO; - dividend_size = dividend->_mp_size; - size = ABS (dividend_size); - - if (quot->_mp_alloc < size) - _mpz_realloc (quot, size); - - quot_ptr = quot->_mp_d; - - remainder_limb = mpn_divmod_1 (quot_ptr, dividend->_mp_d, size, - (mp_limb_t) divisor); - - if (remainder_limb != 0 && dividend_size < 0) + ns = SIZ(dividend); + if (ns == 0) { - mpn_incr_u (quot_ptr, (mp_limb_t) 1); - remainder_limb = divisor - remainder_limb; + SIZ(quot) = 0; + SIZ(rem) = 0; + return 0; } - size -= size != 0 && quot_ptr[size - 1] == 0; - quot->_mp_size = dividend_size >= 0 ? size : -size; + nn = ABS(ns); + MPZ_REALLOC (quot, nn); + qp = PTR(quot); + np = PTR(dividend); - rem->_mp_d[0] = remainder_limb; - rem->_mp_size = remainder_limb != 0; +#if GMP_NAIL_BITS != 0 + if (divisor > GMP_NUMB_MAX) + { + mp_limb_t dp[2]; + mp_ptr rp; + mp_size_t rn; + + MPZ_REALLOC (rem, 2); + rp = PTR(rem); + + if (nn == 1) /* tdiv_qr requirements; tested above for 0 */ + { + qp[0] = 0; + qn = 1; /* a white lie, fixed below */ + rl = np[0]; + rp[0] = rl; + } + else + { + dp[0] = divisor & GMP_NUMB_MASK; + dp[1] = divisor >> GMP_NUMB_BITS; + mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2); + rl = rp[0] + (rp[1] << GMP_NUMB_BITS); + qn = nn - 2 + 1; + } + + if (rl != 0 && ns < 0) + { + mpn_incr_u (qp, (mp_limb_t) 1); + rl = divisor - rl; + rp[0] = rl & GMP_NUMB_MASK; + rp[1] = rl >> GMP_NUMB_BITS; + } + + qn -= qp[qn - 1] == 0; qn -= qn != 0 && qp[qn - 1] == 0; + rn = 1 + (rl > GMP_NUMB_MAX); rn -= (rp[rn - 1] == 0); + SIZ(rem) = rn; + } + else +#endif + { + rl = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, (mp_limb_t) divisor); + if (rl == 0) + SIZ(rem) = 0; + else + { + if (ns < 0) + { + mpn_incr_u (qp, (mp_limb_t) 1); + rl = divisor - rl; + } + + PTR(rem)[0] = rl; + SIZ(rem) = rl != 0; + } + qn = nn - (qp[nn - 1] == 0); + } - return remainder_limb; + SIZ(quot) = ns >= 0 ? qn : -qn; + return rl; } |