diff options
Diffstat (limited to 'gmp-6.3.0/mpn/generic/toom_interpolate_5pts.c')
| -rw-r--r-- | gmp-6.3.0/mpn/generic/toom_interpolate_5pts.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/gmp-6.3.0/mpn/generic/toom_interpolate_5pts.c b/gmp-6.3.0/mpn/generic/toom_interpolate_5pts.c new file mode 100644 index 0000000..466ab85 --- /dev/null +++ b/gmp-6.3.0/mpn/generic/toom_interpolate_5pts.c @@ -0,0 +1,198 @@ +/* mpn_toom_interpolate_5pts -- Interpolate for toom3, 33, 42. + + Contributed to the GNU project by Robert Harley. + Improvements by Paul Zimmermann and Marco Bodrato. + + THE FUNCTION IN THIS FILE IS INTERNAL WITH A MUTABLE INTERFACE. IT IS ONLY + SAFE TO REACH IT THROUGH DOCUMENTED INTERFACES. IN FACT, IT IS ALMOST + GUARANTEED THAT IT WILL CHANGE OR DISAPPEAR IN A FUTURE GNU MP RELEASE. + +Copyright 2000-2003, 2005-2007, 2009 Free Software Foundation, Inc. + +This file is part of the GNU MP Library. + +The GNU MP Library is free software; you can redistribute it and/or modify +it under the terms of either: + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at your + option) any later version. + +or + + * the GNU General Public License as published by the Free Software + Foundation; either version 2 of the License, or (at your option) any + later version. + +or both in parallel, as here. + +The GNU MP 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 General Public License +for more details. + +You should have received copies of the GNU General Public License and the +GNU Lesser General Public License along with the GNU MP Library. If not, +see https://www.gnu.org/licenses/. */ + +#include "gmp-impl.h" + +void +mpn_toom_interpolate_5pts (mp_ptr c, mp_ptr v2, mp_ptr vm1, + mp_size_t k, mp_size_t twor, int sa, + mp_limb_t vinf0) +{ + mp_limb_t cy, saved; + mp_size_t twok; + mp_size_t kk1; + mp_ptr c1, v1, c3, vinf; + + twok = k + k; + kk1 = twok + 1; + + c1 = c + k; + v1 = c1 + k; + c3 = v1 + k; + vinf = c3 + k; + +#define v0 (c) + /* (1) v2 <- v2-vm1 < v2+|vm1|, (16 8 4 2 1) - (1 -1 1 -1 1) = + thus 0 <= v2 < 50*B^(2k) < 2^6*B^(2k) (15 9 3 3 0) + */ + if (sa) + ASSERT_NOCARRY (mpn_add_n (v2, v2, vm1, kk1)); + else + ASSERT_NOCARRY (mpn_sub_n (v2, v2, vm1, kk1)); + + /* {c,2k} {c+2k,2k+1} {c+4k+1,2r-1} {t,2k+1} {t+2k+1,2k+1} {t+4k+2,2r} + v0 v1 hi(vinf) |vm1| v2-vm1 EMPTY */ + + ASSERT_NOCARRY (mpn_divexact_by3 (v2, v2, kk1)); /* v2 <- v2 / 3 */ + /* (5 3 1 1 0)*/ + + /* {c,2k} {c+2k,2k+1} {c+4k+1,2r-1} {t,2k+1} {t+2k+1,2k+1} {t+4k+2,2r} + v0 v1 hi(vinf) |vm1| (v2-vm1)/3 EMPTY */ + + /* (2) vm1 <- tm1 := (v1 - vm1) / 2 [(1 1 1 1 1) - (1 -1 1 -1 1)] / 2 = + tm1 >= 0 (0 1 0 1 0) + No carry comes out from {v1, kk1} +/- {vm1, kk1}, + and the division by two is exact. + If (sa!=0) the sign of vm1 is negative */ + if (sa) + { +#ifdef HAVE_NATIVE_mpn_rsh1add_n + mpn_rsh1add_n (vm1, v1, vm1, kk1); +#else + ASSERT_NOCARRY (mpn_add_n (vm1, v1, vm1, kk1)); + ASSERT_NOCARRY (mpn_rshift (vm1, vm1, kk1, 1)); +#endif + } + else + { +#ifdef HAVE_NATIVE_mpn_rsh1sub_n + mpn_rsh1sub_n (vm1, v1, vm1, kk1); +#else + ASSERT_NOCARRY (mpn_sub_n (vm1, v1, vm1, kk1)); + ASSERT_NOCARRY (mpn_rshift (vm1, vm1, kk1, 1)); +#endif + } + + /* {c,2k} {c+2k,2k+1} {c+4k+1,2r-1} {t,2k+1} {t+2k+1,2k+1} {t+4k+2,2r} + v0 v1 hi(vinf) tm1 (v2-vm1)/3 EMPTY */ + + /* (3) v1 <- t1 := v1 - v0 (1 1 1 1 1) - (0 0 0 0 1) = (1 1 1 1 0) + t1 >= 0 + */ + vinf[0] -= mpn_sub_n (v1, v1, c, twok); + + /* {c,2k} {c+2k,2k+1} {c+4k+1,2r-1} {t,2k+1} {t+2k+1,2k+1} {t+4k+2,2r} + v0 v1-v0 hi(vinf) tm1 (v2-vm1)/3 EMPTY */ + + /* (4) v2 <- t2 := ((v2-vm1)/3-t1)/2 = (v2-vm1-3*t1)/6 + t2 >= 0 [(5 3 1 1 0) - (1 1 1 1 0)]/2 = (2 1 0 0 0) + */ +#ifdef HAVE_NATIVE_mpn_rsh1sub_n + mpn_rsh1sub_n (v2, v2, v1, kk1); +#else + ASSERT_NOCARRY (mpn_sub_n (v2, v2, v1, kk1)); + ASSERT_NOCARRY (mpn_rshift (v2, v2, kk1, 1)); +#endif + + /* {c,2k} {c+2k,2k+1} {c+4k+1,2r-1} {t,2k+1} {t+2k+1,2k+1} {t+4k+2,2r} + v0 v1-v0 hi(vinf) tm1 (v2-vm1-3t1)/6 EMPTY */ + + /* (5) v1 <- t1-tm1 (1 1 1 1 0) - (0 1 0 1 0) = (1 0 1 0 0) + result is v1 >= 0 + */ + ASSERT_NOCARRY (mpn_sub_n (v1, v1, vm1, kk1)); + + /* We do not need to read the value in vm1, so we add it in {c+k, ...} */ + cy = mpn_add_n (c1, c1, vm1, kk1); + MPN_INCR_U (c3 + 1, twor + k - 1, cy); /* 2n-(3k+1) = 2r+k-1 */ + /* Memory allocated for vm1 is now free, it can be recycled ...*/ + + /* (6) v2 <- v2 - 2*vinf, (2 1 0 0 0) - 2*(1 0 0 0 0) = (0 1 0 0 0) + result is v2 >= 0 */ + saved = vinf[0]; /* Remember v1's highest byte (will be overwritten). */ + vinf[0] = vinf0; /* Set the right value for vinf0 */ +#ifdef HAVE_NATIVE_mpn_sublsh1_n_ip1 + cy = mpn_sublsh1_n_ip1 (v2, vinf, twor); +#else + /* Overwrite unused vm1 */ + cy = mpn_lshift (vm1, vinf, twor, 1); + cy += mpn_sub_n (v2, v2, vm1, twor); +#endif + MPN_DECR_U (v2 + twor, kk1 - twor, cy); + + /* Current matrix is + [1 0 0 0 0; vinf + 0 1 0 0 0; v2 + 1 0 1 0 0; v1 + 0 1 0 1 0; vm1 + 0 0 0 0 1] v0 + Some values already are in-place (we added vm1 in the correct position) + | vinf| v1 | v0 | + | vm1 | + One still is in a separated area + | +v2 | + We have to compute v1-=vinf; vm1 -= v2, + |-vinf| + | -v2 | + Carefully reordering operations we can avoid to compute twice the sum + of the high half of v2 plus the low half of vinf. + */ + + /* Add the high half of t2 in {vinf} */ + if ( LIKELY(twor > k + 1) ) { /* This is the expected flow */ + cy = mpn_add_n (vinf, vinf, v2 + k, k + 1); + MPN_INCR_U (c3 + kk1, twor - k - 1, cy); /* 2n-(5k+1) = 2r-k-1 */ + } else { /* triggered only by very unbalanced cases like + (k+k+(k-2))x(k+k+1) , should be handled by toom32 */ + ASSERT_NOCARRY (mpn_add_n (vinf, vinf, v2 + k, twor)); + } + /* (7) v1 <- v1 - vinf, (1 0 1 0 0) - (1 0 0 0 0) = (0 0 1 0 0) + result is >= 0 */ + /* Side effect: we also subtracted (high half) vm1 -= v2 */ + cy = mpn_sub_n (v1, v1, vinf, twor); /* vinf is at most twor long. */ + vinf0 = vinf[0]; /* Save again the right value for vinf0 */ + vinf[0] = saved; + MPN_DECR_U (v1 + twor, kk1 - twor, cy); /* Treat the last bytes. */ + + /* (8) vm1 <- vm1-v2 (0 1 0 1 0) - (0 1 0 0 0) = (0 0 0 1 0) + Operate only on the low half. + */ + cy = mpn_sub_n (c1, c1, v2, k); + MPN_DECR_U (v1, kk1, cy); + + /********************* Beginning the final phase **********************/ + + /* Most of the recomposition was done */ + + /* add t2 in {c+3k, ...}, but only the low half */ + cy = mpn_add_n (c3, c3, v2, k); + vinf[0] += cy; + ASSERT(vinf[0] >= cy); /* No carry */ + MPN_INCR_U (vinf, twor, vinf0); /* Add vinf0, propagate carry. */ + +#undef v0 +} |