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-rw-r--r--libtommath/bn_mp_div.c81
1 files changed, 44 insertions, 37 deletions
diff --git a/libtommath/bn_mp_div.c b/libtommath/bn_mp_div.c
index de4ca04..3ca5d7f 100644
--- a/libtommath/bn_mp_div.c
+++ b/libtommath/bn_mp_div.c
@@ -1,4 +1,4 @@
-#include <tommath.h>
+#include <tommath_private.h>
#ifdef BN_MP_DIV_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
@@ -12,7 +12,7 @@
* The library is free for all purposes without any express
* guarantee it works.
*
- * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
+ * Tom St Denis, tstdenis82@gmail.com, http://libtom.org
*/
#ifdef BN_MP_DIV_SMALL
@@ -24,7 +24,7 @@ int mp_div(mp_int * a, mp_int * b, mp_int * c, mp_int * d)
int res, n, n2;
/* is divisor zero ? */
- if (mp_iszero (b) == 1) {
+ if (mp_iszero (b) == MP_YES) {
return MP_VAL;
}
@@ -40,9 +40,9 @@ int mp_div(mp_int * a, mp_int * b, mp_int * c, mp_int * d)
}
return res;
}
-
+
/* init our temps */
- if ((res = mp_init_multi(&ta, &tb, &tq, &q, NULL) != MP_OKAY)) {
+ if ((res = mp_init_multi(&ta, &tb, &tq, &q, NULL)) != MP_OKAY) {
return res;
}
@@ -50,7 +50,7 @@ int mp_div(mp_int * a, mp_int * b, mp_int * c, mp_int * d)
mp_set(&tq, 1);
n = mp_count_bits(a) - mp_count_bits(b);
if (((res = mp_abs(a, &ta)) != MP_OKAY) ||
- ((res = mp_abs(b, &tb)) != MP_OKAY) ||
+ ((res = mp_abs(b, &tb)) != MP_OKAY) ||
((res = mp_mul_2d(&tb, n, &tb)) != MP_OKAY) ||
((res = mp_mul_2d(&tq, n, &tq)) != MP_OKAY)) {
goto LBL_ERR;
@@ -71,7 +71,7 @@ int mp_div(mp_int * a, mp_int * b, mp_int * c, mp_int * d)
/* now q == quotient and ta == remainder */
n = a->sign;
- n2 = (a->sign == b->sign ? MP_ZPOS : MP_NEG);
+ n2 = (a->sign == b->sign) ? MP_ZPOS : MP_NEG;
if (c != NULL) {
mp_exch(c, &q);
c->sign = (mp_iszero(c) == MP_YES) ? MP_ZPOS : n2;
@@ -87,17 +87,17 @@ LBL_ERR:
#else
-/* integer signed division.
+/* integer signed division.
* c*b + d == a [e.g. a/b, c=quotient, d=remainder]
* HAC pp.598 Algorithm 14.20
*
- * Note that the description in HAC is horribly
- * incomplete. For example, it doesn't consider
- * the case where digits are removed from 'x' in
- * the inner loop. It also doesn't consider the
+ * Note that the description in HAC is horribly
+ * incomplete. For example, it doesn't consider
+ * the case where digits are removed from 'x' in
+ * the inner loop. It also doesn't consider the
* case that y has fewer than three digits, etc..
*
- * The overall algorithm is as described as
+ * The overall algorithm is as described as
* 14.20 from HAC but fixed to treat these cases.
*/
int mp_div (mp_int * a, mp_int * b, mp_int * c, mp_int * d)
@@ -106,7 +106,7 @@ int mp_div (mp_int * a, mp_int * b, mp_int * c, mp_int * d)
int res, n, t, i, norm, neg;
/* is divisor zero ? */
- if (mp_iszero (b) == 1) {
+ if (mp_iszero (b) == MP_YES) {
return MP_VAL;
}
@@ -187,51 +187,52 @@ int mp_div (mp_int * a, mp_int * b, mp_int * c, mp_int * d)
continue;
}
- /* step 3.1 if xi == yt then set q{i-t-1} to b-1,
+ /* step 3.1 if xi == yt then set q{i-t-1} to b-1,
* otherwise set q{i-t-1} to (xi*b + x{i-1})/yt */
if (x.dp[i] == y.dp[t]) {
- q.dp[i - t - 1] = ((((mp_digit)1) << DIGIT_BIT) - 1);
+ q.dp[(i - t) - 1] = ((((mp_digit)1) << DIGIT_BIT) - 1);
} else {
mp_word tmp;
tmp = ((mp_word) x.dp[i]) << ((mp_word) DIGIT_BIT);
tmp |= ((mp_word) x.dp[i - 1]);
tmp /= ((mp_word) y.dp[t]);
- if (tmp > (mp_word) MP_MASK)
+ if (tmp > (mp_word) MP_MASK) {
tmp = MP_MASK;
- q.dp[i - t - 1] = (mp_digit) (tmp & (mp_word) (MP_MASK));
+ }
+ q.dp[(i - t) - 1] = (mp_digit) (tmp & (mp_word) (MP_MASK));
}
- /* while (q{i-t-1} * (yt * b + y{t-1})) >
- xi * b**2 + xi-1 * b + xi-2
-
- do q{i-t-1} -= 1;
+ /* while (q{i-t-1} * (yt * b + y{t-1})) >
+ xi * b**2 + xi-1 * b + xi-2
+
+ do q{i-t-1} -= 1;
*/
- q.dp[i - t - 1] = (q.dp[i - t - 1] + 1) & MP_MASK;
+ q.dp[(i - t) - 1] = (q.dp[(i - t) - 1] + 1) & MP_MASK;
do {
- q.dp[i - t - 1] = (q.dp[i - t - 1] - 1) & MP_MASK;
+ q.dp[(i - t) - 1] = (q.dp[(i - t) - 1] - 1) & MP_MASK;
/* find left hand */
mp_zero (&t1);
- t1.dp[0] = (t - 1 < 0) ? 0 : y.dp[t - 1];
+ t1.dp[0] = ((t - 1) < 0) ? 0 : y.dp[t - 1];
t1.dp[1] = y.dp[t];
t1.used = 2;
- if ((res = mp_mul_d (&t1, q.dp[i - t - 1], &t1)) != MP_OKAY) {
+ if ((res = mp_mul_d (&t1, q.dp[(i - t) - 1], &t1)) != MP_OKAY) {
goto LBL_Y;
}
/* find right hand */
- t2.dp[0] = (i - 2 < 0) ? 0 : x.dp[i - 2];
- t2.dp[1] = (i - 1 < 0) ? 0 : x.dp[i - 1];
+ t2.dp[0] = ((i - 2) < 0) ? 0 : x.dp[i - 2];
+ t2.dp[1] = ((i - 1) < 0) ? 0 : x.dp[i - 1];
t2.dp[2] = x.dp[i];
t2.used = 3;
} while (mp_cmp_mag(&t1, &t2) == MP_GT);
/* step 3.3 x = x - q{i-t-1} * y * b**{i-t-1} */
- if ((res = mp_mul_d (&y, q.dp[i - t - 1], &t1)) != MP_OKAY) {
+ if ((res = mp_mul_d (&y, q.dp[(i - t) - 1], &t1)) != MP_OKAY) {
goto LBL_Y;
}
- if ((res = mp_lshd (&t1, i - t - 1)) != MP_OKAY) {
+ if ((res = mp_lshd (&t1, (i - t) - 1)) != MP_OKAY) {
goto LBL_Y;
}
@@ -244,23 +245,23 @@ int mp_div (mp_int * a, mp_int * b, mp_int * c, mp_int * d)
if ((res = mp_copy (&y, &t1)) != MP_OKAY) {
goto LBL_Y;
}
- if ((res = mp_lshd (&t1, i - t - 1)) != MP_OKAY) {
+ if ((res = mp_lshd (&t1, (i - t) - 1)) != MP_OKAY) {
goto LBL_Y;
}
if ((res = mp_add (&x, &t1, &x)) != MP_OKAY) {
goto LBL_Y;
}
- q.dp[i - t - 1] = (q.dp[i - t - 1] - 1UL) & MP_MASK;
+ q.dp[(i - t) - 1] = (q.dp[(i - t) - 1] - 1UL) & MP_MASK;
}
}
- /* now q is the quotient and x is the remainder
- * [which we have to normalize]
+ /* now q is the quotient and x is the remainder
+ * [which we have to normalize]
*/
-
+
/* get sign before writing to c */
- x.sign = x.used == 0 ? MP_ZPOS : a->sign;
+ x.sign = (x.used == 0) ? MP_ZPOS : a->sign;
if (c != NULL) {
mp_clamp (&q);
@@ -269,7 +270,9 @@ int mp_div (mp_int * a, mp_int * b, mp_int * c, mp_int * d)
}
if (d != NULL) {
- mp_div_2d (&x, norm, &x, NULL);
+ if ((res = mp_div_2d (&x, norm, &x, NULL)) != MP_OKAY) {
+ goto LBL_Y;
+ }
mp_exch (&x, d);
}
@@ -286,3 +289,7 @@ LBL_Q:mp_clear (&q);
#endif
#endif
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */
generated by cgit v0.12 at 2024-11-12 00:11:20 (GMT)