1 /* crypto/bn/bn_nist.c */
3 * Written by Nils Larsch for the OpenSSL project
5 /* ====================================================================
6 * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
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9 * modification, are permitted provided that the following conditions
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51 * ====================================================================
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
62 #define BN_NIST_192_TOP (192+BN_BITS2-1)/BN_BITS2
63 #define BN_NIST_224_TOP (224+BN_BITS2-1)/BN_BITS2
64 #define BN_NIST_256_TOP (256+BN_BITS2-1)/BN_BITS2
65 #define BN_NIST_384_TOP (384+BN_BITS2-1)/BN_BITS2
66 #define BN_NIST_521_TOP (521+BN_BITS2-1)/BN_BITS2
69 static const BN_ULONG _nist_p_192[] =
70 {0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFEULL,
71 0xFFFFFFFFFFFFFFFFULL};
72 static const BN_ULONG _nist_p_224[] =
73 {0x0000000000000001ULL,0xFFFFFFFF00000000ULL,
74 0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL};
75 static const BN_ULONG _nist_p_256[] =
76 {0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL,
77 0x0000000000000000ULL,0xFFFFFFFF00000001ULL};
78 static const BN_ULONG _nist_p_384[] =
79 {0x00000000FFFFFFFFULL,0xFFFFFFFF00000000ULL,
80 0xFFFFFFFFFFFFFFFEULL,0xFFFFFFFFFFFFFFFFULL,
81 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL};
82 static const BN_ULONG _nist_p_521[] =
83 {0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
84 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
85 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
86 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
87 0x00000000000001FFULL};
89 static const BN_ULONG _nist_p_192[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFE,
90 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
91 static const BN_ULONG _nist_p_224[] = {0x00000001,0x00000000,0x00000000,
92 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
93 static const BN_ULONG _nist_p_256[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
94 0x00000000,0x00000000,0x00000000,0x00000001,0xFFFFFFFF};
95 static const BN_ULONG _nist_p_384[] = {0xFFFFFFFF,0x00000000,0x00000000,
96 0xFFFFFFFF,0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
97 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};
98 static const BN_ULONG _nist_p_521[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
99 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
100 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
101 0xFFFFFFFF,0x000001FF};
104 const BIGNUM *BN_get0_nist_prime_192(void)
106 static BIGNUM const_nist_192 = { (BN_ULONG *)_nist_p_192,
107 BN_NIST_192_TOP, BN_NIST_192_TOP, 0, BN_FLG_STATIC_DATA };
108 return &const_nist_192;
111 const BIGNUM *BN_get0_nist_prime_224(void)
113 static BIGNUM const_nist_224 = { (BN_ULONG *)_nist_p_224,
114 BN_NIST_224_TOP, BN_NIST_224_TOP, 0, BN_FLG_STATIC_DATA };
115 return &const_nist_224;
118 const BIGNUM *BN_get0_nist_prime_256(void)
120 static BIGNUM const_nist_256 = { (BN_ULONG *)_nist_p_256,
121 BN_NIST_256_TOP, BN_NIST_256_TOP, 0, BN_FLG_STATIC_DATA };
122 return &const_nist_256;
125 const BIGNUM *BN_get0_nist_prime_384(void)
127 static BIGNUM const_nist_384 = { (BN_ULONG *)_nist_p_384,
128 BN_NIST_384_TOP, BN_NIST_384_TOP, 0, BN_FLG_STATIC_DATA };
129 return &const_nist_384;
132 const BIGNUM *BN_get0_nist_prime_521(void)
134 static BIGNUM const_nist_521 = { (BN_ULONG *)_nist_p_521,
135 BN_NIST_521_TOP, BN_NIST_521_TOP, 0, BN_FLG_STATIC_DATA };
136 return &const_nist_521;
139 #define BN_NIST_ADD_ONE(a) while (!(*(a)=(*(a)+1)&BN_MASK2)) ++(a);
141 static void nist_cp_bn_0(BN_ULONG *buf, BN_ULONG *a, int top, int max)
144 BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);
145 for (i = (top); i != 0; i--)
147 for (i = (max) - (top); i != 0; i--)
148 *_tmp1++ = (BN_ULONG) 0;
151 static void nist_cp_bn(BN_ULONG *buf, BN_ULONG *a, int top)
154 BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);
155 for (i = (top); i != 0; i--)
160 #define bn_cp_64(to, n, from, m) (to)[n] = (m>=0)?((from)[m]):0;
161 #define bn_64_set_0(to, n) (to)[n] = (BN_ULONG)0;
163 #define bn_cp_32(to, n, from, m) (to)[n] = (m>=0)?((from)[m]):0;
164 #define bn_32_set_0(to, n) (to)[n] = (BN_ULONG)0;
166 #define bn_cp_64(to, n, from, m) \
168 bn_cp_32(to, (n)*2, from, (m)*2); \
169 bn_cp_32(to, (n)*2+1, from, (m)*2+1); \
171 #define bn_64_set_0(to, n) \
173 bn_32_set_0(to, (n)*2); \
174 bn_32_set_0(to, (n)*2+1); \
177 #define bn_cp_32(to, n, from, m) (to)[n] = (m>=0)?((from)[m]):0;
178 #define bn_32_set_0(to, n) (to)[n] = (BN_ULONG)0;
180 #endif /* BN_BITS2 != 64 */
183 #define nist_set_192(to, from, a1, a2, a3) \
185 if (a3 != 0) bn_cp_64(to, 0, from, (a3) - 3) else bn_64_set_0(to, 0)\
186 bn_cp_64(to, 1, from, (a2) - 3) \
187 if (a1 != 0) bn_cp_64(to, 2, from, (a1) - 3) else bn_64_set_0(to, 2)\
190 int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
195 register BN_ULONG *r_d, *a_d = a->d;
196 BN_ULONG t_d[BN_NIST_192_TOP],
197 buf[BN_NIST_192_TOP],
198 c_d[BN_NIST_192_TOP],
202 i = BN_ucmp(field, a);
209 return (r == a) ? 1 : (BN_copy(r ,a) != NULL);
211 if (top == BN_NIST_192_TOP)
212 return BN_usub(r, a, field);
216 if (!bn_wexpand(r, BN_NIST_192_TOP))
219 nist_cp_bn(r_d, a_d, BN_NIST_192_TOP);
224 nist_cp_bn_0(buf, a_d + BN_NIST_192_TOP, top - BN_NIST_192_TOP, BN_NIST_192_TOP);
226 nist_set_192(t_d, buf, 0, 3, 3);
227 carry = bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
228 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_192,BN_NIST_192_TOP);
229 mask = ~mask | (0-(size_t)carry);
230 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
232 nist_set_192(t_d, buf, 4, 4, 0);
233 carry = bn_add_words(r_d, res, t_d, BN_NIST_192_TOP);
234 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_192,BN_NIST_192_TOP);
235 mask = ~mask | (0-(size_t)carry);
236 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
238 nist_set_192(t_d, buf, 5, 5, 5)
239 carry = bn_add_words(r_d, res, t_d, BN_NIST_192_TOP);
240 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_192,BN_NIST_192_TOP);
241 mask = ~mask | (0-(size_t)carry);
242 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
244 nist_cp_bn(r_d, res, BN_NIST_192_TOP);
245 r->top = BN_NIST_192_TOP;
251 #define nist_set_224(to, from, a1, a2, a3, a4, a5, a6, a7) \
253 if (a7 != 0) bn_cp_32(to, 0, from, (a7) - 7) else bn_32_set_0(to, 0)\
254 if (a6 != 0) bn_cp_32(to, 1, from, (a6) - 7) else bn_32_set_0(to, 1)\
255 if (a5 != 0) bn_cp_32(to, 2, from, (a5) - 7) else bn_32_set_0(to, 2)\
256 if (a4 != 0) bn_cp_32(to, 3, from, (a4) - 7) else bn_32_set_0(to, 3)\
257 if (a3 != 0) bn_cp_32(to, 4, from, (a3) - 7) else bn_32_set_0(to, 4)\
258 if (a2 != 0) bn_cp_32(to, 5, from, (a2) - 7) else bn_32_set_0(to, 5)\
259 if (a1 != 0) bn_cp_32(to, 6, from, (a1) - 7) else bn_32_set_0(to, 6)\
262 int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
268 BN_ULONG *r_d, *a_d = a->d;
269 BN_ULONG t_d[BN_NIST_224_TOP],
270 buf[BN_NIST_224_TOP],
271 c_d[BN_NIST_224_TOP],
275 i = BN_ucmp(field, a);
282 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
284 if (top == BN_NIST_224_TOP)
285 return BN_usub(r, a, field);
289 if (!bn_wexpand(r, BN_NIST_224_TOP))
292 nist_cp_bn(r_d, a_d, BN_NIST_224_TOP);
297 nist_cp_bn_0(buf, a_d + BN_NIST_224_TOP, top - BN_NIST_224_TOP, BN_NIST_224_TOP);
299 nist_set_224(t_d, buf, 10, 9, 8, 7, 0, 0, 0);
300 carry = bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
301 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
302 mask = ~mask | (0-(size_t)carry);
303 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
305 nist_set_224(t_d, buf, 0, 13, 12, 11, 0, 0, 0);
306 carry = bn_add_words(r_d, res, t_d, BN_NIST_224_TOP);
307 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
308 mask = ~mask | (0-(size_t)carry);
309 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
311 nist_set_224(t_d, buf, 13, 12, 11, 10, 9, 8, 7);
313 carry = bn_sub_words(r_d, res, t_d, BN_NIST_224_TOP);
314 bn_add_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
315 mask = 0-(size_t)carry;
316 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
318 if (bn_sub_words(r_d, res, t_d, BN_NIST_224_TOP))
319 bn_add_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP);
321 nist_set_224(t_d, buf, 0, 0, 0, 0, 13, 12, 11);
323 carry = bn_sub_words(r_d, res, t_d, BN_NIST_224_TOP);
324 bn_add_words(c_d,r_d,_nist_p_224,BN_NIST_224_TOP);
325 mask = 0-(size_t)carry;
326 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
328 nist_cp_bn(r_d, res, BN_NIST_224_TOP);
330 if (bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP))
331 bn_add_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP);
333 r->top = BN_NIST_224_TOP;
337 #else /* BN_BITS!=32 */
342 #define nist_set_256(to, from, a1, a2, a3, a4, a5, a6, a7, a8) \
344 if (a8 != 0) bn_cp_32(to, 0, from, (a8) - 8) else bn_32_set_0(to, 0)\
345 if (a7 != 0) bn_cp_32(to, 1, from, (a7) - 8) else bn_32_set_0(to, 1)\
346 if (a6 != 0) bn_cp_32(to, 2, from, (a6) - 8) else bn_32_set_0(to, 2)\
347 if (a5 != 0) bn_cp_32(to, 3, from, (a5) - 8) else bn_32_set_0(to, 3)\
348 if (a4 != 0) bn_cp_32(to, 4, from, (a4) - 8) else bn_32_set_0(to, 4)\
349 if (a3 != 0) bn_cp_32(to, 5, from, (a3) - 8) else bn_32_set_0(to, 5)\
350 if (a2 != 0) bn_cp_32(to, 6, from, (a2) - 8) else bn_32_set_0(to, 6)\
351 if (a1 != 0) bn_cp_32(to, 7, from, (a1) - 8) else bn_32_set_0(to, 7)\
354 int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
360 register BN_ULONG *a_d = a->d, *r_d;
361 BN_ULONG t_d[BN_NIST_256_TOP],
362 buf[BN_NIST_256_TOP],
363 c_d[BN_NIST_256_TOP],
367 i = BN_ucmp(field, a);
374 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
376 if (top == BN_NIST_256_TOP)
377 return BN_usub(r, a, field);
381 if (!bn_wexpand(r, BN_NIST_256_TOP))
384 nist_cp_bn(r_d, a_d, BN_NIST_256_TOP);
389 nist_cp_bn_0(buf, a_d + BN_NIST_256_TOP, top - BN_NIST_256_TOP, BN_NIST_256_TOP);
392 nist_set_256(t_d, buf, 15, 14, 13, 12, 11, 0, 0, 0);
394 nist_set_256(c_d,buf, 0, 15, 14, 13, 12, 0, 0, 0);
395 carry = bn_add_words(t_d, t_d, c_d, BN_NIST_256_TOP);
396 mask = 0-(size_t)bn_sub_words(c_d,t_d,_nist_p_256,BN_NIST_256_TOP);
397 mask = ~mask | (0-(size_t)carry);
398 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)t_d&~mask));
400 carry = bn_add_words(t_d, res, res, BN_NIST_256_TOP);
401 mask = 0-(size_t)bn_sub_words(c_d,t_d,_nist_p_256,BN_NIST_256_TOP);
402 mask = ~mask | (0-(size_t)carry);
403 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)t_d&~mask));
405 carry = bn_add_words(r_d, r_d, res, BN_NIST_256_TOP);
406 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
407 mask = ~mask | (0-(size_t)carry);
408 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
411 nist_set_256(t_d, buf, 15, 14, 0, 0, 0, 10, 9, 8);
412 carry = bn_add_words(r_d, res, t_d, BN_NIST_256_TOP);
413 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
414 mask = ~mask | (0-(size_t)carry);
415 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
418 nist_set_256(t_d, buf, 8, 13, 15, 14, 13, 11, 10, 9);
419 carry = bn_add_words(r_d, res, t_d, BN_NIST_256_TOP);
420 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
421 mask = ~mask | (0-(size_t)carry);
422 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
425 nist_set_256(t_d, buf, 10, 8, 0, 0, 0, 13, 12, 11);
427 carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
428 bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
429 mask = 0-(size_t)carry;
430 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
432 if (bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP))
433 bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
436 nist_set_256(t_d, buf, 11, 9, 0, 0, 15, 14, 13, 12);
438 carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
439 bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
440 mask = 0-(size_t)carry;
441 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
443 if (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP))
444 bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
447 nist_set_256(t_d, buf, 12, 0, 10, 9, 8, 15, 14, 13);
449 carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
450 bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
451 mask = 0-(size_t)carry;
452 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
454 if (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP))
455 bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
458 nist_set_256(t_d, buf, 13, 0, 11, 10, 9, 0, 15, 14);
460 carry = bn_sub_words(r_d, res, t_d, BN_NIST_256_TOP);
461 bn_add_words(c_d,r_d,_nist_p_256,BN_NIST_256_TOP);
462 mask = 0-(size_t)carry;
463 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
465 nist_cp_bn(r_d, res, BN_NIST_384_TOP);
467 if (bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP))
468 bn_add_words(r_d,r_d,_nist_p_256,BN_NIST_256_TOP);
470 r->top = BN_NIST_256_TOP;
474 #else /* BN_BITS!=32 */
479 #define nist_set_384(to,from,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12) \
481 if (a12 != 0) bn_cp_32(to, 0, from, (a12) - 12) else bn_32_set_0(to, 0)\
482 if (a11 != 0) bn_cp_32(to, 1, from, (a11) - 12) else bn_32_set_0(to, 1)\
483 if (a10 != 0) bn_cp_32(to, 2, from, (a10) - 12) else bn_32_set_0(to, 2)\
484 if (a9 != 0) bn_cp_32(to, 3, from, (a9) - 12) else bn_32_set_0(to, 3)\
485 if (a8 != 0) bn_cp_32(to, 4, from, (a8) - 12) else bn_32_set_0(to, 4)\
486 if (a7 != 0) bn_cp_32(to, 5, from, (a7) - 12) else bn_32_set_0(to, 5)\
487 if (a6 != 0) bn_cp_32(to, 6, from, (a6) - 12) else bn_32_set_0(to, 6)\
488 if (a5 != 0) bn_cp_32(to, 7, from, (a5) - 12) else bn_32_set_0(to, 7)\
489 if (a4 != 0) bn_cp_32(to, 8, from, (a4) - 12) else bn_32_set_0(to, 8)\
490 if (a3 != 0) bn_cp_32(to, 9, from, (a3) - 12) else bn_32_set_0(to, 9)\
491 if (a2 != 0) bn_cp_32(to, 10, from, (a2) - 12) else bn_32_set_0(to, 10)\
492 if (a1 != 0) bn_cp_32(to, 11, from, (a1) - 12) else bn_32_set_0(to, 11)\
495 int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
501 register BN_ULONG *r_d, *a_d = a->d;
502 BN_ULONG t_d[BN_NIST_384_TOP],
503 buf[BN_NIST_384_TOP],
504 c_d[BN_NIST_384_TOP],
508 i = BN_ucmp(field, a);
515 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
517 if (top == BN_NIST_384_TOP)
518 return BN_usub(r, a, field);
522 if (!bn_wexpand(r, BN_NIST_384_TOP))
525 nist_cp_bn(r_d, a_d, BN_NIST_384_TOP);
530 nist_cp_bn_0(buf, a_d + BN_NIST_384_TOP, top - BN_NIST_384_TOP, BN_NIST_384_TOP);
533 nist_set_256(t_d, buf, 0, 0, 0, 0, 0, 23-4, 22-4, 21-4);
536 register BN_ULONG *ap,t,c;
539 for (i = 3; i != 0; --i)
542 *(ap++)=((t<<1)|c)&BN_MASK2;
547 carry = bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2),
548 t_d, BN_NIST_256_TOP);
550 * we need if (result>=modulus) subtract(result,modulus);
551 * in n-bit space this can be expressed as
552 * if (carry || result>=modulus) subtract(result,modulus);
553 * the catch is that comparison implies subtraction and
554 * therefore one can write tmp=subtract(result,modulus);
555 * and then if(carry || !borrow) result=tmp; this's what
556 * happens below, but without explicit if:-) a.
558 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
559 mask = ~mask | (0-(size_t)carry);
560 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
563 carry = bn_add_words(r_d, res, buf, BN_NIST_384_TOP);
564 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
565 mask = ~mask | (0-(size_t)carry);
566 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
569 nist_set_384(t_d,buf,20,19,18,17,16,15,14,13,12,23,22,21);
570 carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
571 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
572 mask = ~mask | (0-(size_t)carry);
573 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
576 nist_set_384(t_d,buf,19,18,17,16,15,14,13,12,20,0,23,0);
577 carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
578 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
579 mask = ~mask | (0-(size_t)carry);
580 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
583 nist_set_384(t_d, buf,0,0,0,0,23,22,21,20,0,0,0,0);
584 carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
585 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
586 mask = ~mask | (0-(size_t)carry);
587 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
590 nist_set_384(t_d,buf,0,0,0,0,0,0,23,22,21,0,0,20);
591 carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP);
592 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
593 mask = ~mask | (0-(size_t)carry);
594 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
597 nist_set_384(t_d,buf,22,21,20,19,18,17,16,15,14,13,12,23);
599 carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP);
600 bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
601 mask = 0-(size_t)carry;
602 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
604 if (bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP))
605 bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP);
608 nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,22,21,20,0);
610 carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP);
611 bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
612 mask = 0-(size_t)carry;
613 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
615 if (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP))
616 bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP);
619 nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,23,0,0,0);
621 carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP);
622 bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP);
623 mask = 0-(size_t)carry;
624 res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask));
626 nist_cp_bn(r_d, res, BN_NIST_384_TOP);
628 if (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP))
629 bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP);
631 r->top = BN_NIST_384_TOP;
635 #else /* BN_BITS!=32 */
640 int BN_nist_mod_521(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
644 #define BN_NIST_521_TOP_MASK (BN_ULONG)0x1FF
646 #define BN_NIST_521_TOP_MASK (BN_ULONG)0x1FF
652 /* check whether a reduction is necessary */
654 if (top < BN_NIST_521_TOP || ( top == BN_NIST_521_TOP &&
655 (!(a->d[BN_NIST_521_TOP-1] & ~(BN_NIST_521_TOP_MASK)))))
656 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
659 tmp = BN_CTX_get(ctx);
663 if (!bn_wexpand(tmp, BN_NIST_521_TOP))
665 nist_cp_bn(tmp->d, a->d, BN_NIST_521_TOP);
667 tmp->top = BN_NIST_521_TOP;
668 tmp->d[BN_NIST_521_TOP-1] &= BN_NIST_521_TOP_MASK;
671 if (!BN_rshift(r, a, 521))
674 if (!BN_uadd(r, tmp, r))
678 if (top == BN_NIST_521_TOP &&
679 (r_d[BN_NIST_521_TOP-1] & ~(BN_NIST_521_TOP_MASK)))
682 r->d[BN_NIST_521_TOP-1] &= BN_NIST_521_TOP_MASK;