1 /* mpn_toom3_sqr -- Square {ap,an}.
3 Contributed to the GNU project by Torbjorn Granlund.
4 Additional improvements by Marco Bodrato.
6 THE FUNCTION IN THIS FILE IS INTERNAL WITH A MUTABLE INTERFACE. IT IS ONLY
7 SAFE TO REACH IT THROUGH DOCUMENTED INTERFACES. IN FACT, IT IS ALMOST
8 GUARANTEED THAT IT WILL CHANGE OR DISAPPEAR IN A FUTURE GNU MP RELEASE.
10 Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
12 This file is part of the GNU MP Library.
14 The GNU MP Library is free software; you can redistribute it and/or modify
15 it under the terms of the GNU Lesser General Public License as published by
16 the Free Software Foundation; either version 3 of the License, or (at your
17 option) any later version.
19 The GNU MP Library is distributed in the hope that it will be useful, but
20 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
21 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
22 License for more details.
24 You should have received a copy of the GNU Lesser General Public License
25 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
31 /* Evaluate in: -1, 0, +1, +2, +inf
38 v1 = (a0+ a1+ a2)^2 # A(1)^2 ah <= 2
39 vm1 = (a0- a1+ a2)^2 # A(-1)^2 |ah| <= 1
40 v2 = (a0+2a1+4a2)^2 # A(2)^2 ah <= 6
41 vinf= a2 ^2 # A(inf)^2
44 #if TUNE_PROGRAM_BUILD
45 #define MAYBE_sqr_basecase 1
46 #define MAYBE_sqr_toom3 1
48 #define MAYBE_sqr_basecase \
49 (SQR_TOOM3_THRESHOLD < 3 * SQR_TOOM2_THRESHOLD)
50 #define MAYBE_sqr_toom3 \
51 (SQR_TOOM4_THRESHOLD >= 3 * SQR_TOOM3_THRESHOLD)
54 #define TOOM3_SQR_REC(p, a, n, ws) \
56 if (MAYBE_sqr_basecase \
57 && BELOW_THRESHOLD (n, SQR_TOOM2_THRESHOLD)) \
58 mpn_sqr_basecase (p, a, n); \
59 else if (! MAYBE_sqr_toom3 \
60 || BELOW_THRESHOLD (n, SQR_TOOM3_THRESHOLD)) \
61 mpn_toom2_sqr (p, a, n, ws); \
63 mpn_toom3_sqr (p, a, n, ws); \
67 mpn_toom3_sqr (mp_ptr pp,
68 mp_srcptr ap, mp_size_t an,
74 mp_ptr as1, asm1, as2;
80 n = (an + 2) / (size_t) 3;
84 ASSERT (0 < s && s <= n);
86 as1 = scratch + 4 * n + 4;
87 asm1 = scratch + 2 * n + 2;
92 /* Compute as1 and asm1. */
93 cy = mpn_add (gp, a0, n, a2, s);
94 #if HAVE_NATIVE_mpn_add_n_sub_n
95 if (cy == 0 && mpn_cmp (gp, a1, n) < 0)
97 cy = mpn_add_n_sub_n (as1, asm1, a1, gp, n);
103 cy2 = mpn_add_n_sub_n (as1, asm1, gp, a1, n);
104 as1[n] = cy + (cy2 >> 1);
105 asm1[n] = cy - (cy & 1);
108 as1[n] = cy + mpn_add_n (as1, gp, a1, n);
109 if (cy == 0 && mpn_cmp (gp, a1, n) < 0)
111 mpn_sub_n (asm1, a1, gp, n);
116 cy -= mpn_sub_n (asm1, gp, a1, n);
122 #if HAVE_NATIVE_mpn_rsblsh1_n
123 cy = mpn_add_n (as2, a2, as1, s);
125 cy = mpn_add_1 (as2 + s, as1 + s, n - s, cy);
127 cy = 2 * cy + mpn_rsblsh1_n (as2, a0, as2, n);
129 #if HAVE_NATIVE_mpn_addlsh1_n
130 cy = mpn_addlsh1_n (as2, a1, a2, s);
132 cy = mpn_add_1 (as2 + s, a1 + s, n - s, cy);
133 cy = 2 * cy + mpn_addlsh1_n (as2, a0, as2, n);
135 cy = mpn_add_n (as2, a2, as1, s);
137 cy = mpn_add_1 (as2 + s, as1 + s, n - s, cy);
139 cy = 2 * cy + mpn_lshift (as2, as2, n, 1);
140 cy -= mpn_sub_n (as2, as2, a0, n);
145 ASSERT (as1[n] <= 2);
146 ASSERT (asm1[n] <= 1);
148 #define v0 pp /* 2n */
149 #define v1 (pp + 2 * n) /* 2n+1 */
150 #define vinf (pp + 4 * n) /* s+s */
151 #define vm1 scratch /* 2n+1 */
152 #define v2 (scratch + 2 * n + 1) /* 2n+2 */
153 #define scratch_out (scratch + 5 * n + 5)
155 /* vm1, 2n+1 limbs */
156 #ifdef SMALLER_RECURSION
157 TOOM3_SQR_REC (vm1, asm1, n, scratch_out);
160 cy = asm1[n] + mpn_add_n (vm1 + n, vm1 + n, asm1, n);
162 cy += mpn_add_n (vm1 + n, vm1 + n, asm1, n);
165 TOOM3_SQR_REC (vm1, asm1, n + 1, scratch_out);
168 TOOM3_SQR_REC (v2, as2, n + 1, scratch_out); /* v2, 2n+1 limbs */
170 TOOM3_SQR_REC (vinf, a2, s, scratch_out); /* vinf, s+s limbs */
172 vinf0 = vinf[0]; /* v1 overlaps with this */
174 #ifdef SMALLER_RECURSION
176 TOOM3_SQR_REC (v1, as1, n, scratch_out);
179 cy = as1[n] + mpn_add_n (v1 + n, v1 + n, as1, n);
181 else if (as1[n] != 0)
183 #if HAVE_NATIVE_mpn_addlsh1_n
184 cy = 2 * as1[n] + mpn_addlsh1_n (v1 + n, v1 + n, as1, n);
186 cy = 2 * as1[n] + mpn_addmul_1 (v1 + n, as1, n, CNST_LIMB(2));
193 cy += mpn_add_n (v1 + n, v1 + n, as1, n);
195 else if (as1[n] != 0)
197 #if HAVE_NATIVE_mpn_addlsh1_n
198 cy += mpn_addlsh1_n (v1 + n, v1 + n, as1, n);
200 cy += mpn_addmul_1 (v1 + n, as1, n, CNST_LIMB(2));
206 TOOM3_SQR_REC (v1, as1, n + 1, scratch_out);
210 TOOM3_SQR_REC (v0, ap, n, scratch_out); /* v0, 2n limbs */
212 mpn_toom_interpolate_5pts (pp, v2, vm1, n, s + s, 0, vinf0);