void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)
{
    BN_ULONG *rr;
    if (na < nb) {
        int itmp;
        BN_ULONG *ltmp;
        itmp = na;
        na = nb;
        nb = itmp;
        ltmp = a;
        a = b;
        b = ltmp;
    }
    rr = &(r[na]);
    if (nb <= 0) {
        (void)bn_mul_words(r, a, na, 0);
        return;
    } else
        rr[0] = bn_mul_words(r, a, na, b[0]);
    for (;;) {
        if (--nb <= 0)
            return;
        rr[1] = bn_mul_add_words(&(r[1]), a, na, b[1]);
        if (--nb <= 0)
            return;
        rr[2] = bn_mul_add_words(&(r[2]), a, na, b[2]);
        if (--nb <= 0)
            return;
        rr[3] = bn_mul_add_words(&(r[3]), a, na, b[3]);
        if (--nb <= 0)
            return;
        rr[4] = bn_mul_add_words(&(r[4]), a, na, b[4]);
        rr += 4;
        r += 4;
        b += 4;
    }
}
['static int test_div_recip()\n{\n    BIGNUM *a, *b, *c, *d, *e;\n    BN_RECP_CTX *recp;\n    int i;\n    recp = BN_RECP_CTX_new();\n    a = BN_new();\n    b = BN_new();\n    c = BN_new();\n    d = BN_new();\n    e = BN_new();\n    for (i = 0; i < NUM0 + NUM1; i++) {\n        if (i < NUM1) {\n            BN_bntest_rand(a, 400, 0, 0);\n            BN_copy(b, a);\n            BN_lshift(a, a, i);\n            BN_add_word(a, i);\n        } else\n            BN_bntest_rand(b, 50 + 3 * (i - NUM1), 0, 0);\n        a->neg = rand_neg();\n        b->neg = rand_neg();\n        BN_RECP_CTX_set(recp, b, ctx);\n        BN_div_recp(d, c, a, recp, ctx);\n        BN_mul(e, d, b, ctx);\n        BN_add(d, e, c);\n        BN_sub(d, d, a);\n        if (!BN_is_zero(d)) {\n            printf("Reciprocal division test failed!\\n");\n            printf("a=");\n            BN_print_fp(stdout, a);\n            printf("\\nb=");\n            BN_print_fp(stdout, b);\n            printf("\\n");\n            return 0;\n        }\n    }\n    BN_free(a);\n    BN_free(b);\n    BN_free(c);\n    BN_free(d);\n    BN_free(e);\n    BN_RECP_CTX_free(recp);\n    return 1;\n}', 'int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx)\n{\n    if (!BN_copy(&(recp->N), d))\n        return 0;\n    BN_zero(&(recp->Nr));\n    recp->num_bits = BN_num_bits(d);\n    recp->shift = 0;\n    return (1);\n}', 'BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)\n{\n    int i;\n    BN_ULONG *A;\n    const BN_ULONG *B;\n    bn_check_top(b);\n    if (a == b)\n        return (a);\n    if (bn_wexpand(a, b->top) == NULL)\n        return (NULL);\n#if 1\n    A = a->d;\n    B = b->d;\n    for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {\n        BN_ULONG a0, a1, a2, a3;\n        a0 = B[0];\n        a1 = B[1];\n        a2 = B[2];\n        a3 = B[3];\n        A[0] = a0;\n        A[1] = a1;\n        A[2] = a2;\n        A[3] = a3;\n    }\n    switch (b->top & 3) {\n    case 3:\n        A[2] = B[2];\n    case 2:\n        A[1] = B[1];\n    case 1:\n        A[0] = B[0];\n    case 0:;\n    }\n#else\n    memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);\n#endif\n    a->top = b->top;\n    a->neg = b->neg;\n    bn_check_top(a);\n    return (a);\n}', 'int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,\n                BN_RECP_CTX *recp, BN_CTX *ctx)\n{\n    int i, j, ret = 0;\n    BIGNUM *a, *b, *d, *r;\n    BN_CTX_start(ctx);\n    a = BN_CTX_get(ctx);\n    b = BN_CTX_get(ctx);\n    if (dv != NULL)\n        d = dv;\n    else\n        d = BN_CTX_get(ctx);\n    if (rem != NULL)\n        r = rem;\n    else\n        r = BN_CTX_get(ctx);\n    if (a == NULL || b == NULL || d == NULL || r == NULL)\n        goto err;\n    if (BN_ucmp(m, &(recp->N)) < 0) {\n        BN_zero(d);\n        if (!BN_copy(r, m)) {\n            BN_CTX_end(ctx);\n            return 0;\n        }\n        BN_CTX_end(ctx);\n        return (1);\n    }\n    i = BN_num_bits(m);\n    j = recp->num_bits << 1;\n    if (j > i)\n        i = j;\n    if (i != recp->shift)\n        recp->shift = BN_reciprocal(&(recp->Nr), &(recp->N), i, ctx);\n    if (recp->shift == -1)\n        goto err;\n    if (!BN_rshift(a, m, recp->num_bits))\n        goto err;\n    if (!BN_mul(b, a, &(recp->Nr), ctx))\n        goto err;\n    if (!BN_rshift(d, b, i - recp->num_bits))\n        goto err;\n    d->neg = 0;\n    if (!BN_mul(b, &(recp->N), d, ctx))\n        goto err;\n    if (!BN_usub(r, m, b))\n        goto err;\n    r->neg = 0;\n    j = 0;\n    while (BN_ucmp(r, &(recp->N)) >= 0) {\n        if (j++ > 2) {\n            BNerr(BN_F_BN_DIV_RECP, BN_R_BAD_RECIPROCAL);\n            goto err;\n        }\n        if (!BN_usub(r, r, &(recp->N)))\n            goto err;\n        if (!BN_add_word(d, 1))\n            goto err;\n    }\n    r->neg = BN_is_zero(r) ? 0 : m->neg;\n    d->neg = m->neg ^ recp->N.neg;\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    bn_check_top(dv);\n    bn_check_top(rem);\n    return (ret);\n}', 'int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)\n{\n    int ret = 0;\n    int top, al, bl;\n    BIGNUM *rr;\n#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)\n    int i;\n#endif\n#ifdef BN_RECURSION\n    BIGNUM *t = NULL;\n    int j = 0, k;\n#endif\n    bn_check_top(a);\n    bn_check_top(b);\n    bn_check_top(r);\n    al = a->top;\n    bl = b->top;\n    if ((al == 0) || (bl == 0)) {\n        BN_zero(r);\n        return (1);\n    }\n    top = al + bl;\n    BN_CTX_start(ctx);\n    if ((r == a) || (r == b)) {\n        if ((rr = BN_CTX_get(ctx)) == NULL)\n            goto err;\n    } else\n        rr = r;\n    rr->neg = a->neg ^ b->neg;\n#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)\n    i = al - bl;\n#endif\n#ifdef BN_MUL_COMBA\n    if (i == 0) {\n# if 0\n        if (al == 4) {\n            if (bn_wexpand(rr, 8) == NULL)\n                goto err;\n            rr->top = 8;\n            bn_mul_comba4(rr->d, a->d, b->d);\n            goto end;\n        }\n# endif\n        if (al == 8) {\n            if (bn_wexpand(rr, 16) == NULL)\n                goto err;\n            rr->top = 16;\n            bn_mul_comba8(rr->d, a->d, b->d);\n            goto end;\n        }\n    }\n#endif\n#ifdef BN_RECURSION\n    if ((al >= BN_MULL_SIZE_NORMAL) && (bl >= BN_MULL_SIZE_NORMAL)) {\n        if (i >= -1 && i <= 1) {\n            if (i >= 0) {\n                j = BN_num_bits_word((BN_ULONG)al);\n            }\n            if (i == -1) {\n                j = BN_num_bits_word((BN_ULONG)bl);\n            }\n            j = 1 << (j - 1);\n            assert(j <= al || j <= bl);\n            k = j + j;\n            t = BN_CTX_get(ctx);\n            if (t == NULL)\n                goto err;\n            if (al > j || bl > j) {\n                if (bn_wexpand(t, k * 4) == NULL)\n                    goto err;\n                if (bn_wexpand(rr, k * 4) == NULL)\n                    goto err;\n                bn_mul_part_recursive(rr->d, a->d, b->d,\n                                      j, al - j, bl - j, t->d);\n            } else {\n                if (bn_wexpand(t, k * 2) == NULL)\n                    goto err;\n                if (bn_wexpand(rr, k * 2) == NULL)\n                    goto err;\n                bn_mul_recursive(rr->d, a->d, b->d, j, al - j, bl - j, t->d);\n            }\n            rr->top = top;\n            goto end;\n        }\n# if 0\n        if (i == 1 && !BN_get_flags(b, BN_FLG_STATIC_DATA)) {\n            BIGNUM *tmp_bn = (BIGNUM *)b;\n            if (bn_wexpand(tmp_bn, al) == NULL)\n                goto err;\n            tmp_bn->d[bl] = 0;\n            bl++;\n            i--;\n        } else if (i == -1 && !BN_get_flags(a, BN_FLG_STATIC_DATA)) {\n            BIGNUM *tmp_bn = (BIGNUM *)a;\n            if (bn_wexpand(tmp_bn, bl) == NULL)\n                goto err;\n            tmp_bn->d[al] = 0;\n            al++;\n            i++;\n        }\n        if (i == 0) {\n            j = BN_num_bits_word((BN_ULONG)al);\n            j = 1 << (j - 1);\n            k = j + j;\n            t = BN_CTX_get(ctx);\n            if (al == j) {\n                if (bn_wexpand(t, k * 2) == NULL)\n                    goto err;\n                if (bn_wexpand(rr, k * 2) == NULL)\n                    goto err;\n                bn_mul_recursive(rr->d, a->d, b->d, al, t->d);\n            } else {\n                if (bn_wexpand(t, k * 4) == NULL)\n                    goto err;\n                if (bn_wexpand(rr, k * 4) == NULL)\n                    goto err;\n                bn_mul_part_recursive(rr->d, a->d, b->d, al - j, j, t->d);\n            }\n            rr->top = top;\n            goto end;\n        }\n# endif\n    }\n#endif\n    if (bn_wexpand(rr, top) == NULL)\n        goto err;\n    rr->top = top;\n    bn_mul_normal(rr->d, a->d, al, b->d, bl);\n#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)\n end:\n#endif\n    bn_correct_top(rr);\n    if (r != rr && BN_copy(r, rr) == NULL)\n        goto err;\n    ret = 1;\n err:\n    bn_check_top(r);\n    BN_CTX_end(ctx);\n    return (ret);\n}', 'void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n,\n                           int tna, int tnb, BN_ULONG *t)\n{\n    int i, j, n2 = n * 2;\n    int c1, c2, neg;\n    BN_ULONG ln, lo, *p;\n    if (n < 8) {\n        bn_mul_normal(r, a, n + tna, b, n + tnb);\n        return;\n    }\n    c1 = bn_cmp_part_words(a, &(a[n]), tna, n - tna);\n    c2 = bn_cmp_part_words(&(b[n]), b, tnb, tnb - n);\n    neg = 0;\n    switch (c1 * 3 + c2) {\n    case -4:\n        bn_sub_part_words(t, &(a[n]), a, tna, tna - n);\n        bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb);\n        break;\n    case -3:\n    case -2:\n        bn_sub_part_words(t, &(a[n]), a, tna, tna - n);\n        bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n);\n        neg = 1;\n        break;\n    case -1:\n    case 0:\n    case 1:\n    case 2:\n        bn_sub_part_words(t, a, &(a[n]), tna, n - tna);\n        bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb);\n        neg = 1;\n        break;\n    case 3:\n    case 4:\n        bn_sub_part_words(t, a, &(a[n]), tna, n - tna);\n        bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n);\n        break;\n    }\n# if 0\n    if (n == 4) {\n        bn_mul_comba4(&(t[n2]), t, &(t[n]));\n        bn_mul_comba4(r, a, b);\n        bn_mul_normal(&(r[n2]), &(a[n]), tn, &(b[n]), tn);\n        memset(&r[n2 + tn * 2], 0, sizeof(*r) * (n2 - tn * 2));\n    } else\n# endif\n    if (n == 8) {\n        bn_mul_comba8(&(t[n2]), t, &(t[n]));\n        bn_mul_comba8(r, a, b);\n        bn_mul_normal(&(r[n2]), &(a[n]), tna, &(b[n]), tnb);\n        memset(&r[n2 + tna + tnb], 0, sizeof(*r) * (n2 - tna - tnb));\n    } else {\n        p = &(t[n2 * 2]);\n        bn_mul_recursive(&(t[n2]), t, &(t[n]), n, 0, 0, p);\n        bn_mul_recursive(r, a, b, n, 0, 0, p);\n        i = n / 2;\n        if (tna > tnb)\n            j = tna - i;\n        else\n            j = tnb - i;\n        if (j == 0) {\n            bn_mul_recursive(&(r[n2]), &(a[n]), &(b[n]),\n                             i, tna - i, tnb - i, p);\n            memset(&r[n2 + i * 2], 0, sizeof(*r) * (n2 - i * 2));\n        } else if (j > 0) {\n            bn_mul_part_recursive(&(r[n2]), &(a[n]), &(b[n]),\n                                  i, tna - i, tnb - i, p);\n            memset(&(r[n2 + tna + tnb]), 0,\n                   sizeof(BN_ULONG) * (n2 - tna - tnb));\n        } else {\n            memset(&r[n2], 0, sizeof(*r) * n2);\n            if (tna < BN_MUL_RECURSIVE_SIZE_NORMAL\n                && tnb < BN_MUL_RECURSIVE_SIZE_NORMAL) {\n                bn_mul_normal(&(r[n2]), &(a[n]), tna, &(b[n]), tnb);\n            } else {\n                for (;;) {\n                    i /= 2;\n                    if (i < tna || i < tnb) {\n                        bn_mul_part_recursive(&(r[n2]),\n                                              &(a[n]), &(b[n]),\n                                              i, tna - i, tnb - i, p);\n                        break;\n                    } else if (i == tna || i == tnb) {\n                        bn_mul_recursive(&(r[n2]),\n                                         &(a[n]), &(b[n]),\n                                         i, tna - i, tnb - i, p);\n                        break;\n                    }\n                }\n            }\n        }\n    }\n    c1 = (int)(bn_add_words(t, r, &(r[n2]), n2));\n    if (neg) {\n        c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2));\n    } else {\n        c1 += (int)(bn_add_words(&(t[n2]), &(t[n2]), t, n2));\n    }\n    c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2));\n    if (c1) {\n        p = &(r[n + n2]);\n        lo = *p;\n        ln = (lo + c1) & BN_MASK2;\n        *p = ln;\n        if (ln < (BN_ULONG)c1) {\n            do {\n                p++;\n                lo = *p;\n                ln = (lo + 1) & BN_MASK2;\n                *p = ln;\n            } while (ln == 0);\n        }\n    }\n}', 'void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)\n{\n    BN_ULONG *rr;\n    if (na < nb) {\n        int itmp;\n        BN_ULONG *ltmp;\n        itmp = na;\n        na = nb;\n        nb = itmp;\n        ltmp = a;\n        a = b;\n        b = ltmp;\n    }\n    rr = &(r[na]);\n    if (nb <= 0) {\n        (void)bn_mul_words(r, a, na, 0);\n        return;\n    } else\n        rr[0] = bn_mul_words(r, a, na, b[0]);\n    for (;;) {\n        if (--nb <= 0)\n            return;\n        rr[1] = bn_mul_add_words(&(r[1]), a, na, b[1]);\n        if (--nb <= 0)\n            return;\n        rr[2] = bn_mul_add_words(&(r[2]), a, na, b[2]);\n        if (--nb <= 0)\n            return;\n        rr[3] = bn_mul_add_words(&(r[3]), a, na, b[3]);\n        if (--nb <= 0)\n            return;\n        rr[4] = bn_mul_add_words(&(r[4]), a, na, b[4]);\n        rr += 4;\n        r += 4;\n        b += 4;\n    }\n}']