1 /* mpiutil.ac  -  Utility functions for MPI
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * You should have received a copy of the GNU General Public License
18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
21 #include "mpi-internal.h"
56 			return -EFAULT;  in mpi_init()
59 		constants[idx]->flags = (16|32);  in mpi_init()
66 /* Return a constant MPI descripbed by NO which is one of the
81  * Note:  It was a bad idea to use the number of limbs to allocate
82  *	  because on a alpha the limbs are large but we normally need
83  *	  integers of n bits - So we should change this to bits (or bytes).
85  *	  But mpi_alloc is used in a lot of places :-)
89 	MPI a;  in mpi_alloc()  local
91 	a = kmalloc(sizeof *a, GFP_KERNEL);  in mpi_alloc()
92 	if (!a)  in mpi_alloc()
93 		return a;  in mpi_alloc()
96 		a->d = mpi_alloc_limb_space(nlimbs);  in mpi_alloc()
97 		if (!a->d) {  in mpi_alloc()
98 			kfree(a);  in mpi_alloc()
102 		a->d = NULL;  in mpi_alloc()
105 	a->alloced = nlimbs;  in mpi_alloc()
106 	a->nlimbs = 0;  in mpi_alloc()
107 	a->sign = 0;  in mpi_alloc()
108 	a->flags = 0;  in mpi_alloc()
109 	a->nbits = 0;  in mpi_alloc()
110 	return a;  in mpi_alloc()
124 void mpi_free_limb_space(mpi_ptr_t a)  in mpi_free_limb_space()  argument
126 	if (!a)  in mpi_free_limb_space()
129 	kfree_sensitive(a);  in mpi_free_limb_space()
132 void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)  in mpi_assign_limb_space()  argument
134 	mpi_free_limb_space(a->d);  in mpi_assign_limb_space()
135 	a->d = ap;  in mpi_assign_limb_space()
136 	a->alloced = nlimbs;  in mpi_assign_limb_space()
140  * Resize the array of A to NLIMBS. the additional space is cleared
143 int mpi_resize(MPI a, unsigned nlimbs)  in mpi_resize()  argument
147 	if (nlimbs <= a->alloced)  in mpi_resize()
150 	if (a->d) {  in mpi_resize()
153 			return -ENOMEM;  in mpi_resize()
154 		memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));  in mpi_resize()
155 		kfree_sensitive(a->d);  in mpi_resize()
156 		a->d = p;  in mpi_resize()
158 		a->d = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL);  in mpi_resize()
159 		if (!a->d)  in mpi_resize()
160 			return -ENOMEM;  in mpi_resize()
162 	a->alloced = nlimbs;  in mpi_resize()
166 void mpi_clear(MPI a)  in mpi_clear()  argument
168 	if (!a)  in mpi_clear()
170 	a->nlimbs = 0;  in mpi_clear()
171 	a->flags = 0;  in mpi_clear()
175 void mpi_free(MPI a)  in mpi_free()  argument
177 	if (!a)  in mpi_free()
180 	if (a->flags & 4)  in mpi_free()
181 		kfree_sensitive(a->d);  in mpi_free()
183 		mpi_free_limb_space(a->d);  in mpi_free()
185 	if (a->flags & ~7)  in mpi_free()
187 	kfree(a);  in mpi_free()
195 MPI mpi_copy(MPI a)  in mpi_copy()  argument
200 	if (a) {  in mpi_copy()
201 		b = mpi_alloc(a->nlimbs);  in mpi_copy()
202 		b->nlimbs = a->nlimbs;  in mpi_copy()
203 		b->sign = a->sign;  in mpi_copy()
204 		b->flags = a->flags;  in mpi_copy()
205 		b->flags &= ~(16|32); /* Reset the immutable and constant flags. */  in mpi_copy()
206 		for (i = 0; i < b->nlimbs; i++)  in mpi_copy()
207 			b->d[i] = a->d[i];  in mpi_copy()
215  * a value as large as the one given in the argument and allocates it
216  * with the same flags as A.
218 MPI mpi_alloc_like(MPI a)  in mpi_alloc_like()  argument
222 	if (a) {  in mpi_alloc_like()
223 		b = mpi_alloc(a->nlimbs);  in mpi_alloc_like()
224 		b->nlimbs = 0;  in mpi_alloc_like()
225 		b->sign = 0;  in mpi_alloc_like()
226 		b->flags = a->flags;  in mpi_alloc_like()
238 		mpi_assign_limb_space(w, u->d, u->alloced);  in mpi_snatch()
239 		w->nlimbs = u->nlimbs;  in mpi_snatch()
240 		w->sign   = u->sign;  in mpi_snatch()
241 		w->flags  = u->flags;  in mpi_snatch()
242 		u->alloced = 0;  in mpi_snatch()
243 		u->nlimbs = 0;  in mpi_snatch()
244 		u->d = NULL;  in mpi_snatch()
253 	mpi_size_t usize = u->nlimbs;  in mpi_set()
254 	int usign = u->sign;  in mpi_set()
259 	wp = w->d;  in mpi_set()
260 	up = u->d;  in mpi_set()
262 	w->nlimbs = usize;  in mpi_set()
263 	w->flags = u->flags;  in mpi_set()
264 	w->flags &= ~(16|32); /* Reset the immutable and constant flags.  */  in mpi_set()
265 	w->sign = usign;  in mpi_set()
278 	w->d[0] = u;  in mpi_set_ui()
279 	w->nlimbs = u ? 1 : 0;  in mpi_set_ui()
280 	w->sign = 0;  in mpi_set_ui()
281 	w->flags = 0;  in mpi_set_ui()
289 	w->d[0] = u;  in mpi_alloc_set_ui()
290 	w->nlimbs = u ? 1 : 0;  in mpi_alloc_set_ui()
291 	w->sign = 0;  in mpi_alloc_set_ui()
296  * Swap the value of A and B, when SWAP is 1.
298  * This implementation should be constant-time regardless of SWAP.
300 void mpi_swap_cond(MPI a, MPI b, unsigned long swap)  in mpi_swap_cond()  argument
304 	mpi_limb_t mask = ((mpi_limb_t)0) - swap;  in mpi_swap_cond()
307 	if (a->alloced > b->alloced)  in mpi_swap_cond()
308 		nlimbs = b->alloced;  in mpi_swap_cond()
310 		nlimbs = a->alloced;  in mpi_swap_cond()
311 	if (a->nlimbs > nlimbs || b->nlimbs > nlimbs)  in mpi_swap_cond()
315 		x = mask & (a->d[i] ^ b->d[i]);  in mpi_swap_cond()
316 		a->d[i] = a->d[i] ^ x;  in mpi_swap_cond()
317 		b->d[i] = b->d[i] ^ x;  in mpi_swap_cond()
320 	x = mask & (a->nlimbs ^ b->nlimbs);  in mpi_swap_cond()
321 	a->nlimbs = a->nlimbs ^ x;  in mpi_swap_cond()
322 	b->nlimbs = b->nlimbs ^ x;  in mpi_swap_cond()
324 	x = mask & (a->sign ^ b->sign);  in mpi_swap_cond()
325 	a->sign = a->sign ^ x;  in mpi_swap_cond()
326 	b->sign = b->sign ^ x;  in mpi_swap_cond()