Commit d5aa14dd authored by Emilia Kasper's avatar Emilia Kasper
Browse files

Remove memcpy unrolling in bn_lib.c 



Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
Reviewed-by: default avatarAndy Polyakov <appro@openssl.org>
parent c26f655f

crypto/bn/bn_lib.c

+10 −80
Original line number Diff line number Diff line
@@ -245,9 +245,7 @@ BIGNUM *BN_new(void) 
/* The caller MUST check that words > b->dmax before calling this */

static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)

{

    BN_ULONG *A, *a = NULL;

    const BN_ULONG *B;

    int i;

    BN_ULONG *a = NULL;



    bn_check_top(b);
@@ -260,56 +258,18 @@ static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words) 
        return (NULL);

    }

    if (BN_get_flags(b, BN_FLG_SECURE))

        a = A = OPENSSL_secure_zalloc(words * sizeof(*a));

        a = OPENSSL_secure_zalloc(words * sizeof(*a));

    else

        a = A = OPENSSL_zalloc(words * sizeof(*a));

    if (A == NULL) {

        a = OPENSSL_zalloc(words * sizeof(*a));

    if (a == NULL) {

        BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);

        return (NULL);

    }



#if 1

    B = b->d;

    /* Check if the previous number needs to be copied */

    if (B != NULL) {

        for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {

            /*

             * The fact that the loop is unrolled

             * 4-wise is a tribute to Intel. It's

             * the one that doesn't have enough

             * registers to accommodate more data.

             * I'd unroll it 8-wise otherwise:-)

             *

             *              <appro@fy.chalmers.se>

             */

            BN_ULONG a0, a1, a2, a3;

            a0 = B[0];

            a1 = B[1];

            a2 = B[2];

            a3 = B[3];

            A[0] = a0;

            A[1] = a1;

            A[2] = a2;

            A[3] = a3;

        }

        switch (b->top & 3) {

        case 3:

            A[2] = B[2];

        case 2:

            A[1] = B[1];

        case 1:

            A[0] = B[0];

        case 0:

            /* Without the "case 0" some old optimizers got this wrong. */

            ;

        }

    }

#else

    memset(A, 0, sizeof(*A) * words);

    memcpy(A, b->d, sizeof(b->d[0]) * b->top);

#endif

    assert(b->top <= words);

    memcpy(a, b->d, sizeof(*a) * b->top);



    return (a);

    return a;

}



/*
@@ -361,49 +321,19 @@ BIGNUM *BN_dup(const BIGNUM *a) 


BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)

{

    int i;

    BN_ULONG *A;

    const BN_ULONG *B;



    bn_check_top(b);



    if (a == b)

        return (a);

        return a;

    if (bn_wexpand(a, b->top) == NULL)

        return (NULL);

        return NULL;



#if 1

    A = a->d;

    B = b->d;

    for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {

        BN_ULONG a0, a1, a2, a3;

        a0 = B[0];

        a1 = B[1];

        a2 = B[2];

        a3 = B[3];

        A[0] = a0;

        A[1] = a1;

        A[2] = a2;

        A[3] = a3;

    }

    /* ultrix cc workaround, see comments in bn_expand_internal */

    switch (b->top & 3) {

    case 3:

        A[2] = B[2];

    case 2:

        A[1] = B[1];

    case 1:

        A[0] = B[0];

    case 0:;

    }

#else

    memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);

#endif



    a->top = b->top;

    a->neg = b->neg;

    bn_check_top(a);

    return (a);

    return a;

}



void BN_swap(BIGNUM *a, BIGNUM *b)