openssl/crypto/bn/bn_asm.c

/* crypto/bn/bn_asm.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#ifndef BN_DEBUG
# undef NDEBUG                  /* avoid conflicting definitions */
# define NDEBUG
#endif

#include <stdio.h>
#include <assert.h>
#include "cryptlib.h"
#include "bn_lcl.h"

#if defined(BN_LLONG) || defined(BN_UMULT_HIGH)

BN_ULONG bn_mul_add_words(BN_ULONG *rp, const BN_ULONG *ap, int num,
                          BN_ULONG w)
{
    BN_ULONG c1 = 0;

    assert(num >= 0);
    if (num <= 0)
        return (c1);

    while (num & ~3) {
        mul_add(rp[0], ap[0], w, c1);
        mul_add(rp[1], ap[1], w, c1);
        mul_add(rp[2], ap[2], w, c1);
        mul_add(rp[3], ap[3], w, c1);
        ap += 4;
        rp += 4;
        num -= 4;
    }
    if (num) {
        mul_add(rp[0], ap[0], w, c1);
        if (--num == 0)
            return c1;
        mul_add(rp[1], ap[1], w, c1);
        if (--num == 0)
            return c1;
        mul_add(rp[2], ap[2], w, c1);
        return c1;
    }

    return (c1);
}

BN_ULONG bn_mul_words(BN_ULONG *rp, const BN_ULONG *ap, int num, BN_ULONG w)
{
    BN_ULONG c1 = 0;

    assert(num >= 0);
    if (num <= 0)
        return (c1);

    while (num & ~3) {
        mul(rp[0], ap[0], w, c1);
        mul(rp[1], ap[1], w, c1);
        mul(rp[2], ap[2], w, c1);
        mul(rp[3], ap[3], w, c1);
        ap += 4;
        rp += 4;
        num -= 4;
    }
    if (num) {
        mul(rp[0], ap[0], w, c1);
        if (--num == 0)
            return c1;
        mul(rp[1], ap[1], w, c1);
        if (--num == 0)
            return c1;
        mul(rp[2], ap[2], w, c1);
    }
    return (c1);
}

void bn_sqr_words(BN_ULONG *r, const BN_ULONG *a, int n)
{
    assert(n >= 0);
    if (n <= 0)
        return;
    while (n & ~3) {
        sqr(r[0], r[1], a[0]);
        sqr(r[2], r[3], a[1]);
        sqr(r[4], r[5], a[2]);
        sqr(r[6], r[7], a[3]);
        a += 4;
        r += 8;
        n -= 4;
    }
    if (n) {
        sqr(r[0], r[1], a[0]);
        if (--n == 0)
            return;
        sqr(r[2], r[3], a[1]);
        if (--n == 0)
            return;
        sqr(r[4], r[5], a[2]);
    }
}

#else                           /* !(defined(BN_LLONG) ||
                                 * defined(BN_UMULT_HIGH)) */

BN_ULONG bn_mul_add_words(BN_ULONG *rp, const BN_ULONG *ap, int num,
                          BN_ULONG w)
{
    BN_ULONG c = 0;
    BN_ULONG bl, bh;

    assert(num >= 0);
    if (num <= 0)
        return ((BN_ULONG)0);

    bl = LBITS(w);
    bh = HBITS(w);

    for (;;) {
        mul_add(rp[0], ap[0], bl, bh, c);
        if (--num == 0)
            break;
        mul_add(rp[1], ap[1], bl, bh, c);
        if (--num == 0)
            break;
        mul_add(rp[2], ap[2], bl, bh, c);
        if (--num == 0)
            break;
        mul_add(rp[3], ap[3], bl, bh, c);
        if (--num == 0)
            break;
        ap += 4;
        rp += 4;
    }
    return (c);
}

BN_ULONG bn_mul_words(BN_ULONG *rp, const BN_ULONG *ap, int num, BN_ULONG w)
{
    BN_ULONG carry = 0;
    BN_ULONG bl, bh;

    assert(num >= 0);
    if (num <= 0)
        return ((BN_ULONG)0);

    bl = LBITS(w);
    bh = HBITS(w);

    for (;;) {
        mul(rp[0], ap[0], bl, bh, carry);
        if (--num == 0)
            break;
        mul(rp[1], ap[1], bl, bh, carry);
        if (--num == 0)
            break;
        mul(rp[2], ap[2], bl, bh, carry);
        if (--num == 0)
            break;
        mul(rp[3], ap[3], bl, bh, carry);
        if (--num == 0)
            break;
        ap += 4;
        rp += 4;
    }
    return (carry);
}

void bn_sqr_words(BN_ULONG *r, const BN_ULONG *a, int n)
{
    assert(n >= 0);
    if (n <= 0)
        return;
    for (;;) {
        sqr64(r[0], r[1], a[0]);
        if (--n == 0)
            break;

        sqr64(r[2], r[3], a[1]);
        if (--n == 0)
            break;

        sqr64(r[4], r[5], a[2]);
        if (--n == 0)
            break;

        sqr64(r[6], r[7], a[3]);
        if (--n == 0)
            break;

        a += 4;
        r += 8;
    }
}

#endif                          /* !(defined(BN_LLONG) ||
                                 * defined(BN_UMULT_HIGH)) */

#if defined(BN_LLONG) && defined(BN_DIV2W)

BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d)
{
    return ((BN_ULONG)(((((BN_ULLONG) h) << BN_BITS2) | l) / (BN_ULLONG) d));
}

#else

/* Divide h,l by d and return the result. */
/* I need to test this some more :-( */
BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d)
{
    BN_ULONG dh, dl, q, ret = 0, th, tl, t;
    int i, count = 2;

    if (d == 0)
        return (BN_MASK2);

    i = BN_num_bits_word(d);
    assert((i == BN_BITS2) || (h <= (BN_ULONG)1 << i));

    i = BN_BITS2 - i;
    if (h >= d)
        h -= d;

    if (i) {
        d <<= i;
        h = (h << i) | (l >> (BN_BITS2 - i));
        l <<= i;
    }
    dh = (d & BN_MASK2h) >> BN_BITS4;
    dl = (d & BN_MASK2l);
    for (;;) {
        if ((h >> BN_BITS4) == dh)
            q = BN_MASK2l;
        else
            q = h / dh;

        th = q * dh;
        tl = dl * q;
        for (;;) {
            t = h - th;
            if ((t & BN_MASK2h) ||
                ((tl) <= ((t << BN_BITS4) | ((l & BN_MASK2h) >> BN_BITS4))))
                break;
            q--;
            th -= dh;
            tl -= dl;
        }
        t = (tl >> BN_BITS4);
        tl = (tl << BN_BITS4) & BN_MASK2h;
        th += t;

        if (l < tl)
            th++;
        l -= tl;
        if (h < th) {
            h += d;
            q--;
        }
        h -= th;

        if (--count == 0)
            break;

        ret = q << BN_BITS4;
        h = ((h << BN_BITS4) | (l >> BN_BITS4)) & BN_MASK2;
        l = (l & BN_MASK2l) << BN_BITS4;
    }
    ret |= q;
    return (ret);
}
#endif                          /* !defined(BN_LLONG) && defined(BN_DIV2W) */

#ifdef BN_LLONG
BN_ULONG bn_add_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b,
                      int n)
{
    BN_ULLONG ll = 0;

    assert(n >= 0);
    if (n <= 0)
        return ((BN_ULONG)0);

    for (;;) {
        ll += (BN_ULLONG) a[0] + b[0];
        r[0] = (BN_ULONG)ll & BN_MASK2;
        ll >>= BN_BITS2;
        if (--n <= 0)
            break;

        ll += (BN_ULLONG) a[1] + b[1];
        r[1] = (BN_ULONG)ll & BN_MASK2;
        ll >>= BN_BITS2;
        if (--n <= 0)
            break;

        ll += (BN_ULLONG) a[2] + b[2];
        r[2] = (BN_ULONG)ll & BN_MASK2;
        ll >>= BN_BITS2;
        if (--n <= 0)
            break;

        ll += (BN_ULLONG) a[3] + b[3];
        r[3] = (BN_ULONG)ll & BN_MASK2;
        ll >>= BN_BITS2;
        if (--n <= 0)
            break;

        a += 4;
        b += 4;
        r += 4;
    }
    return ((BN_ULONG)ll);
}
#else                           /* !BN_LLONG */
BN_ULONG bn_add_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b,
                      int n)
{
    BN_ULONG c, l, t;

    assert(n >= 0);
    if (n <= 0)
        return ((BN_ULONG)0);

    c = 0;
    for (;;) {
        t = a[0];
        t = (t + c) & BN_MASK2;
        c = (t < c);
        l = (t + b[0]) & BN_MASK2;
        c += (l < t);
        r[0] = l;
        if (--n <= 0)
            break;

        t = a[1];
        t = (t + c) & BN_MASK2;
        c = (t < c);
        l = (t + b[1]) & BN_MASK2;
        c += (l < t);
        r[1] = l;
        if (--n <= 0)
            break;

        t = a[2];
        t = (t + c) & BN_MASK2;
        c = (t < c);
        l = (t + b[2]) & BN_MASK2;
        c += (l < t);
        r[2] = l;
        if (--n <= 0)
            break;

        t = a[3];
        t = (t + c) & BN_MASK2;
        c = (t < c);
        l = (t + b[3]) & BN_MASK2;
        c += (l < t);
        r[3] = l;
        if (--n <= 0)
            break;

        a += 4;
        b += 4;
        r += 4;
    }
    return ((BN_ULONG)c);
}
#endif                          /* !BN_LLONG */

BN_ULONG bn_sub_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b,
                      int n)
{
    BN_ULONG t1, t2;
    int c = 0;

    assert(n >= 0);
    if (n <= 0)
        return ((BN_ULONG)0);

    for (;;) {
        t1 = a[0];
        t2 = b[0];
        r[0] = (t1 - t2 - c) & BN_MASK2;
        if (t1 != t2)
            c = (t1 < t2);
        if (--n <= 0)
            break;

        t1 = a[1];
        t2 = b[1];
        r[1] = (t1 - t2 - c) & BN_MASK2;
        if (t1 != t2)
            c = (t1 < t2);
        if (--n <= 0)
            break;

        t1 = a[2];
        t2 = b[2];
        r[2] = (t1 - t2 - c) & BN_MASK2;
        if (t1 != t2)
            c = (t1 < t2);
        if (--n <= 0)
            break;

        t1 = a[3];
        t2 = b[3];
        r[3] = (t1 - t2 - c) & BN_MASK2;
        if (t1 != t2)
            c = (t1 < t2);
        if (--n <= 0)
            break;

        a += 4;
        b += 4;
        r += 4;
    }
    return (c);
}

#ifdef BN_MUL_COMBA

# undef bn_mul_comba8
# undef bn_mul_comba4
# undef bn_sqr_comba8
# undef bn_sqr_comba4

/* mul_add_c(a,b,c0,c1,c2)  -- c+=a*b for three word number c=(c2,c1,c0) */
/* mul_add_c2(a,b,c0,c1,c2) -- c+=2*a*b for three word number c=(c2,c1,c0) */
/* sqr_add_c(a,i,c0,c1,c2)  -- c+=a[i]^2 for three word number c=(c2,c1,c0) */
/*
 * sqr_add_c2(a,i,c0,c1,c2) -- c+=2*a[i]*a[j] for three word number
 * c=(c2,c1,c0)
 */

/*
 * Keep in mind that carrying into high part of multiplication result
 * can not overflow, because it cannot be all-ones.
 */
# ifdef BN_LLONG
#  define mul_add_c(a,b,c0,c1,c2) \
        t=(BN_ULLONG)a*b; \
        t1=(BN_ULONG)Lw(t); \
        t2=(BN_ULONG)Hw(t); \
        c0=(c0+t1)&BN_MASK2; if ((c0) < t1) t2++; \
        c1=(c1+t2)&BN_MASK2; if ((c1) < t2) c2++;

#  define mul_add_c2(a,b,c0,c1,c2) \
        t=(BN_ULLONG)a*b; \
        tt=(t+t)&BN_MASK; \
        if (tt < t) c2++; \
        t1=(BN_ULONG)Lw(tt); \
        t2=(BN_ULONG)Hw(tt); \
        c0=(c0+t1)&BN_MASK2;  \
        if ((c0 < t1) && (((++t2)&BN_MASK2) == 0)) c2++; \
        c1=(c1+t2)&BN_MASK2; if ((c1) < t2) c2++;

#  define sqr_add_c(a,i,c0,c1,c2) \
        t=(BN_ULLONG)a[i]*a[i]; \
        t1=(BN_ULONG)Lw(t); \
        t2=(BN_ULONG)Hw(t); \
        c0=(c0+t1)&BN_MASK2; if ((c0) < t1) t2++; \
        c1=(c1+t2)&BN_MASK2; if ((c1) < t2) c2++;

#  define sqr_add_c2(a,i,j,c0,c1,c2) \
        mul_add_c2((a)[i],(a)[j],c0,c1,c2)

# elif defined(BN_UMULT_LOHI)

#  define mul_add_c(a,b,c0,c1,c2) {       \
        BN_ULONG ta=(a),tb=(b);         \
        BN_UMULT_LOHI(t1,t2,ta,tb);     \
        c0 += t1; t2 += (c0<t1)?1:0;    \
        c1 += t2; c2 += (c1<t2)?1:0;    \
        }

#  define mul_add_c2(a,b,c0,c1,c2) {      \
        BN_ULONG ta=(a),tb=(b),t0;      \
        BN_UMULT_LOHI(t0,t1,ta,tb);     \
        c0 += t0; t2 = t1+((c0<t0)?1:0);\
        c1 += t2; c2 += (c1<t2)?1:0;    \
        c0 += t0; t1 += (c0<t0)?1:0;    \
        c1 += t1; c2 += (c1<t1)?1:0;    \
        }

#  define sqr_add_c(a,i,c0,c1,c2) {       \
        BN_ULONG ta=(a)[i];             \
        BN_UMULT_LOHI(t1,t2,ta,ta);     \
        c0 += t1; t2 += (c0<t1)?1:0;    \
        c1 += t2; c2 += (c1<t2)?1:0;    \
        }

#  define sqr_add_c2(a,i,j,c0,c1,c2)    \
        mul_add_c2((a)[i],(a)[j],c0,c1,c2)

# elif defined(BN_UMULT_HIGH)

#  define mul_add_c(a,b,c0,c1,c2) {       \
        BN_ULONG ta=(a),tb=(b);         \
        t1 = ta * tb;                   \
        t2 = BN_UMULT_HIGH(ta,tb);      \
        c0 += t1; t2 += (c0<t1)?1:0;    \
        c1 += t2; c2 += (c1<t2)?1:0;    \
        }

#  define mul_add_c2(a,b,c0,c1,c2) {      \
        BN_ULONG ta=(a),tb=(b),t0;      \
        t1 = BN_UMULT_HIGH(ta,tb);      \
        t0 = ta * tb;                   \
        c0 += t0; t2 = t1+((c0<t0)?1:0);\
        c1 += t2; c2 += (c1<t2)?1:0;    \
        c0 += t0; t1 += (c0<t0)?1:0;    \
        c1 += t1; c2 += (c1<t1)?1:0;    \
        }

#  define sqr_add_c(a,i,c0,c1,c2) {       \
        BN_ULONG ta=(a)[i];             \
        t1 = ta * ta;                   \
        t2 = BN_UMULT_HIGH(ta,ta);      \
        c0 += t1; t2 += (c0<t1)?1:0;    \
        c1 += t2; c2 += (c1<t2)?1:0;    \
        }

#  define sqr_add_c2(a,i,j,c0,c1,c2)      \
        mul_add_c2((a)[i],(a)[j],c0,c1,c2)

# else                          /* !BN_LLONG */
#  define mul_add_c(a,b,c0,c1,c2) \
        t1=LBITS(a); t2=HBITS(a); \
        bl=LBITS(b); bh=HBITS(b); \
        mul64(t1,t2,bl,bh); \
        c0=(c0+t1)&BN_MASK2; if ((c0) < t1) t2++; \
        c1=(c1+t2)&BN_MASK2; if ((c1) < t2) c2++;

#  define mul_add_c2(a,b,c0,c1,c2) \
        t1=LBITS(a); t2=HBITS(a); \
        bl=LBITS(b); bh=HBITS(b); \
        mul64(t1,t2,bl,bh); \
        if (t2 & BN_TBIT) c2++; \
        t2=(t2+t2)&BN_MASK2; \
        if (t1 & BN_TBIT) t2++; \
        t1=(t1+t1)&BN_MASK2; \
        c0=(c0+t1)&BN_MASK2;  \
        if ((c0 < t1) && (((++t2)&BN_MASK2) == 0)) c2++; \
        c1=(c1+t2)&BN_MASK2; if ((c1) < t2) c2++;

#  define sqr_add_c(a,i,c0,c1,c2) \
        sqr64(t1,t2,(a)[i]); \
        c0=(c0+t1)&BN_MASK2; if ((c0) < t1) t2++; \
        c1=(c1+t2)&BN_MASK2; if ((c1) < t2) c2++;

#  define sqr_add_c2(a,i,j,c0,c1,c2) \
        mul_add_c2((a)[i],(a)[j],c0,c1,c2)
# endif                         /* !BN_LLONG */

void bn_mul_comba8(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
{
# ifdef BN_LLONG
    BN_ULLONG t;
# else
    BN_ULONG bl, bh;
# endif
    BN_ULONG t1, t2;
    BN_ULONG c1, c2, c3;

    c1 = 0;
    c2 = 0;
    c3 = 0;
    mul_add_c(a[0], b[0], c1, c2, c3);
    r[0] = c1;
    c1 = 0;
    mul_add_c(a[0], b[1], c2, c3, c1);
    mul_add_c(a[1], b[0], c2, c3, c1);
    r[1] = c2;
    c2 = 0;
    mul_add_c(a[2], b[0], c3, c1, c2);
    mul_add_c(a[1], b[1], c3, c1, c2);
    mul_add_c(a[0], b[2], c3, c1, c2);
    r[2] = c3;
    c3 = 0;
    mul_add_c(a[0], b[3], c1, c2, c3);
    mul_add_c(a[1], b[2], c1, c2, c3);
    mul_add_c(a[2], b[1], c1, c2, c3);
    mul_add_c(a[3], b[0], c1, c2, c3);
    r[3] = c1;
    c1 = 0;
    mul_add_c(a[4], b[0], c2, c3, c1);
    mul_add_c(a[3], b[1], c2, c3, c1);
    mul_add_c(a[2], b[2], c2, c3, c1);
    mul_add_c(a[1], b[3], c2, c3, c1);
    mul_add_c(a[0], b[4], c2, c3, c1);
    r[4] = c2;
    c2 = 0;
    mul_add_c(a[0], b[5], c3, c1, c2);
    mul_add_c(a[1], b[4], c3, c1, c2);
    mul_add_c(a[2], b[3], c3, c1, c2);
    mul_add_c(a[3], b[2], c3, c1, c2);
    mul_add_c(a[4], b[1], c3, c1, c2);
    mul_add_c(a[5], b[0], c3, c1, c2);
    r[5] = c3;
    c3 = 0;
    mul_add_c(a[6], b[0], c1, c2, c3);
    mul_add_c(a[5], b[1], c1, c2, c3);
    mul_add_c(a[4], b[2], c1, c2, c3);
    mul_add_c(a[3], b[3], c1, c2, c3);
    mul_add_c(a[2], b[4], c1, c2, c3);
    mul_add_c(a[1], b[5], c1, c2, c3);
    mul_add_c(a[0], b[6], c1, c2, c3);
    r[6] = c1;
    c1 = 0;
    mul_add_c(a[0], b[7], c2, c3, c1);
    mul_add_c(a[1], b[6], c2, c3, c1);
    mul_add_c(a[2], b[5], c2, c3, c1);
    mul_add_c(a[3], b[4], c2, c3, c1);
    mul_add_c(a[4], b[3], c2, c3, c1);
    mul_add_c(a[5], b[2], c2, c3, c1);
    mul_add_c(a[6], b[1], c2, c3, c1);
    mul_add_c(a[7], b[0], c2, c3, c1);
    r[7] = c2;
    c2 = 0;
    mul_add_c(a[7], b[1], c3, c1, c2);
    mul_add_c(a[6], b[2], c3, c1, c2);
    mul_add_c(a[5], b[3], c3, c1, c2);
    mul_add_c(a[4], b[4], c3, c1, c2);
    mul_add_c(a[3], b[5], c3, c1, c2);
    mul_add_c(a[2], b[6], c3, c1, c2);
    mul_add_c(a[1], b[7], c3, c1, c2);
    r[8] = c3;
    c3 = 0;
    mul_add_c(a[2], b[7], c1, c2, c3);
    mul_add_c(a[3], b[6], c1, c2, c3);
    mul_add_c(a[4], b[5], c1, c2, c3);
    mul_add_c(a[5], b[4], c1, c2, c3);
    mul_add_c(a[6], b[3], c1, c2, c3);
    mul_add_c(a[7], b[2], c1, c2, c3);
    r[9] = c1;
    c1 = 0;
    mul_add_c(a[7], b[3], c2, c3, c1);
    mul_add_c(a[6], b[4], c2, c3, c1);
    mul_add_c(a[5], b[5], c2, c3, c1);
    mul_add_c(a[4], b[6], c2, c3, c1);
    mul_add_c(a[3], b[7], c2, c3, c1);
    r[10] = c2;
    c2 = 0;
    mul_add_c(a[4], b[7], c3, c1, c2);
    mul_add_c(a[5], b[6], c3, c1, c2);
    mul_add_c(a[6], b[5], c3, c1, c2);
    mul_add_c(a[7], b[4], c3, c1, c2);
    r[11] = c3;
    c3 = 0;
    mul_add_c(a[7], b[5], c1, c2, c3);
    mul_add_c(a[6], b[6], c1, c2, c3);
    mul_add_c(a[5], b[7], c1, c2, c3);
    r[12] = c1;
    c1 = 0;
    mul_add_c(a[6], b[7], c2, c3, c1);
    mul_add_c(a[7], b[6], c2, c3, c1);
    r[13] = c2;
    c2 = 0;
    mul_add_c(a[7], b[7], c3, c1, c2);
    r[14] = c3;
    r[15] = c1;
}

void bn_mul_comba4(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
{
# ifdef BN_LLONG
    BN_ULLONG t;
# else
    BN_ULONG bl, bh;
# endif
    BN_ULONG t1, t2;
    BN_ULONG c1, c2, c3;

    c1 = 0;
    c2 = 0;
    c3 = 0;
    mul_add_c(a[0], b[0], c1, c2, c3);
    r[0] = c1;
    c1 = 0;
    mul_add_c(a[0], b[1], c2, c3, c1);
    mul_add_c(a[1], b[0], c2, c3, c1);
    r[1] = c2;
    c2 = 0;
    mul_add_c(a[2], b[0], c3, c1, c2);
    mul_add_c(a[1], b[1], c3, c1, c2);
    mul_add_c(a[0], b[2], c3, c1, c2);
    r[2] = c3;
    c3 = 0;
    mul_add_c(a[0], b[3], c1, c2, c3);
    mul_add_c(a[1], b[2], c1, c2, c3);
    mul_add_c(a[2], b[1], c1, c2, c3);
    mul_add_c(a[3], b[0], c1, c2, c3);
    r[3] = c1;
    c1 = 0;
    mul_add_c(a[3], b[1], c2, c3, c1);
    mul_add_c(a[2], b[2], c2, c3, c1);
    mul_add_c(a[1], b[3], c2, c3, c1);
    r[4] = c2;
    c2 = 0;
    mul_add_c(a[2], b[3], c3, c1, c2);
    mul_add_c(a[3], b[2], c3, c1, c2);
    r[5] = c3;
    c3 = 0;
    mul_add_c(a[3], b[3], c1, c2, c3);
    r[6] = c1;
    r[7] = c2;
}

void bn_sqr_comba8(BN_ULONG *r, const BN_ULONG *a)
{
# ifdef BN_LLONG
    BN_ULLONG t, tt;
# else
    BN_ULONG bl, bh;
# endif
    BN_ULONG t1, t2;
    BN_ULONG c1, c2, c3;

    c1 = 0;
    c2 = 0;
    c3 = 0;
    sqr_add_c(a, 0, c1, c2, c3);
    r[0] = c1;
    c1 = 0;
    sqr_add_c2(a, 1, 0, c2, c3, c1);
    r[1] = c2;
    c2 = 0;
    sqr_add_c(a, 1, c3, c1, c2);
    sqr_add_c2(a, 2, 0, c3, c1, c2);
    r[2] = c3;
    c3 = 0;
    sqr_add_c2(a, 3, 0, c1, c2, c3);
    sqr_add_c2(a, 2, 1, c1, c2, c3);
    r[3] = c1;
    c1 = 0;
    sqr_add_c(a, 2, c2, c3, c1);
    sqr_add_c2(a, 3, 1, c2, c3, c1);
    sqr_add_c2(a, 4, 0, c2, c3, c1);
    r[4] = c2;
    c2 = 0;
    sqr_add_c2(a, 5, 0, c3, c1, c2);
    sqr_add_c2(a, 4, 1, c3, c1, c2);
    sqr_add_c2(a, 3, 2, c3, c1, c2);
    r[5] = c3;
    c3 = 0;
    sqr_add_c(a, 3, c1, c2, c3);
    sqr_add_c2(a, 4, 2, c1, c2, c3);
    sqr_add_c2(a, 5, 1, c1, c2, c3);
    sqr_add_c2(a, 6, 0, c1, c2, c3);
    r[6] = c1;
    c1 = 0;
    sqr_add_c2(a, 7, 0, c2, c3, c1);
    sqr_add_c2(a, 6, 1, c2, c3, c1);
    sqr_add_c2(a, 5, 2, c2, c3, c1);
    sqr_add_c2(a, 4, 3, c2, c3, c1);
    r[7] = c2;
    c2 = 0;
    sqr_add_c(a, 4, c3, c1, c2);
    sqr_add_c2(a, 5, 3, c3, c1, c2);
    sqr_add_c2(a, 6, 2, c3, c1, c2);
    sqr_add_c2(a, 7, 1, c3, c1, c2);
    r[8] = c3;
    c3 = 0;
    sqr_add_c2(a, 7, 2, c1, c2, c3);
    sqr_add_c2(a, 6, 3, c1, c2, c3);
    sqr_add_c2(a, 5, 4, c1, c2, c3);
    r[9] = c1;
    c1 = 0;
    sqr_add_c(a, 5, c2, c3, c1);
    sqr_add_c2(a, 6, 4, c2, c3, c1);
    sqr_add_c2(a, 7, 3, c2, c3, c1);
    r[10] = c2;
    c2 = 0;
    sqr_add_c2(a, 7, 4, c3, c1, c2);
    sqr_add_c2(a, 6, 5, c3, c1, c2);
    r[11] = c3;
    c3 = 0;
    sqr_add_c(a, 6, c1, c2, c3);
    sqr_add_c2(a, 7, 5, c1, c2, c3);
    r[12] = c1;
    c1 = 0;
    sqr_add_c2(a, 7, 6, c2, c3, c1);
    r[13] = c2;
    c2 = 0;
    sqr_add_c(a, 7, c3, c1, c2);
    r[14] = c3;
    r[15] = c1;
}

void bn_sqr_comba4(BN_ULONG *r, const BN_ULONG *a)
{
# ifdef BN_LLONG
    BN_ULLONG t, tt;
# else
    BN_ULONG bl, bh;
# endif
    BN_ULONG t1, t2;
    BN_ULONG c1, c2, c3;

    c1 = 0;
    c2 = 0;
    c3 = 0;
    sqr_add_c(a, 0, c1, c2, c3);
    r[0] = c1;
    c1 = 0;
    sqr_add_c2(a, 1, 0, c2, c3, c1);
    r[1] = c2;
    c2 = 0;
    sqr_add_c(a, 1, c3, c1, c2);
    sqr_add_c2(a, 2, 0, c3, c1, c2);
    r[2] = c3;
    c3 = 0;
    sqr_add_c2(a, 3, 0, c1, c2, c3);
    sqr_add_c2(a, 2, 1, c1, c2, c3);
    r[3] = c1;
    c1 = 0;
    sqr_add_c(a, 2, c2, c3, c1);
    sqr_add_c2(a, 3, 1, c2, c3, c1);
    r[4] = c2;
    c2 = 0;
    sqr_add_c2(a, 3, 2, c3, c1, c2);
    r[5] = c3;
    c3 = 0;
    sqr_add_c(a, 3, c1, c2, c3);
    r[6] = c1;
    r[7] = c2;
}
#else                           /* !BN_MUL_COMBA */

/* hmm... is it faster just to do a multiply? */
# undef bn_sqr_comba4
void bn_sqr_comba4(BN_ULONG *r, BN_ULONG *a)
{
    BN_ULONG t[8];
    bn_sqr_normal(r, a, 4, t);
}

# undef bn_sqr_comba8
void bn_sqr_comba8(BN_ULONG *r, BN_ULONG *a)
{
    BN_ULONG t[16];
    bn_sqr_normal(r, a, 8, t);
}

void bn_mul_comba4(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
{
    r[4] = bn_mul_words(&(r[0]), a, 4, b[0]);
    r[5] = bn_mul_add_words(&(r[1]), a, 4, b[1]);
    r[6] = bn_mul_add_words(&(r[2]), a, 4, b[2]);
    r[7] = bn_mul_add_words(&(r[3]), a, 4, b[3]);
}

void bn_mul_comba8(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
{
    r[8] = bn_mul_words(&(r[0]), a, 8, b[0]);
    r[9] = bn_mul_add_words(&(r[1]), a, 8, b[1]);
    r[10] = bn_mul_add_words(&(r[2]), a, 8, b[2]);
    r[11] = bn_mul_add_words(&(r[3]), a, 8, b[3]);
    r[12] = bn_mul_add_words(&(r[4]), a, 8, b[4]);
    r[13] = bn_mul_add_words(&(r[5]), a, 8, b[5]);
    r[14] = bn_mul_add_words(&(r[6]), a, 8, b[6]);
    r[15] = bn_mul_add_words(&(r[7]), a, 8, b[7]);
}

#endif                          /* !BN_MUL_COMBA */