mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
![Herbert Xu](/assets/img/avatar_default.png)
This patch removes a number of unused variables and marks others
as unused in order to silence compiler warnings about them.
Fixes: a8ea8bdd9d
("lib/mpi: Extend the MPI library")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
234 lines
5.9 KiB
C
234 lines
5.9 KiB
C
/* mpi-div.c - MPI functions
|
|
* Copyright (C) 1994, 1996, 1998, 2001, 2002,
|
|
* 2003 Free Software Foundation, Inc.
|
|
*
|
|
* This file is part of Libgcrypt.
|
|
*
|
|
* Note: This code is heavily based on the GNU MP Library.
|
|
* Actually it's the same code with only minor changes in the
|
|
* way the data is stored; this is to support the abstraction
|
|
* of an optional secure memory allocation which may be used
|
|
* to avoid revealing of sensitive data due to paging etc.
|
|
*/
|
|
|
|
#include "mpi-internal.h"
|
|
#include "longlong.h"
|
|
|
|
void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den);
|
|
void mpi_fdiv_qr(MPI quot, MPI rem, MPI dividend, MPI divisor);
|
|
|
|
void mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor)
|
|
{
|
|
int divisor_sign = divisor->sign;
|
|
MPI temp_divisor = NULL;
|
|
|
|
/* We need the original value of the divisor after the remainder has been
|
|
* preliminary calculated. We have to copy it to temporary space if it's
|
|
* the same variable as REM.
|
|
*/
|
|
if (rem == divisor) {
|
|
temp_divisor = mpi_copy(divisor);
|
|
divisor = temp_divisor;
|
|
}
|
|
|
|
mpi_tdiv_r(rem, dividend, divisor);
|
|
|
|
if (((divisor_sign?1:0) ^ (dividend->sign?1:0)) && rem->nlimbs)
|
|
mpi_add(rem, rem, divisor);
|
|
|
|
if (temp_divisor)
|
|
mpi_free(temp_divisor);
|
|
}
|
|
|
|
void mpi_fdiv_q(MPI quot, MPI dividend, MPI divisor)
|
|
{
|
|
MPI tmp = mpi_alloc(mpi_get_nlimbs(quot));
|
|
mpi_fdiv_qr(quot, tmp, dividend, divisor);
|
|
mpi_free(tmp);
|
|
}
|
|
|
|
void mpi_fdiv_qr(MPI quot, MPI rem, MPI dividend, MPI divisor)
|
|
{
|
|
int divisor_sign = divisor->sign;
|
|
MPI temp_divisor = NULL;
|
|
|
|
if (quot == divisor || rem == divisor) {
|
|
temp_divisor = mpi_copy(divisor);
|
|
divisor = temp_divisor;
|
|
}
|
|
|
|
mpi_tdiv_qr(quot, rem, dividend, divisor);
|
|
|
|
if ((divisor_sign ^ dividend->sign) && rem->nlimbs) {
|
|
mpi_sub_ui(quot, quot, 1);
|
|
mpi_add(rem, rem, divisor);
|
|
}
|
|
|
|
if (temp_divisor)
|
|
mpi_free(temp_divisor);
|
|
}
|
|
|
|
/* If den == quot, den needs temporary storage.
|
|
* If den == rem, den needs temporary storage.
|
|
* If num == quot, num needs temporary storage.
|
|
* If den has temporary storage, it can be normalized while being copied,
|
|
* i.e no extra storage should be allocated.
|
|
*/
|
|
|
|
void mpi_tdiv_r(MPI rem, MPI num, MPI den)
|
|
{
|
|
mpi_tdiv_qr(NULL, rem, num, den);
|
|
}
|
|
|
|
void mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den)
|
|
{
|
|
mpi_ptr_t np, dp;
|
|
mpi_ptr_t qp, rp;
|
|
mpi_size_t nsize = num->nlimbs;
|
|
mpi_size_t dsize = den->nlimbs;
|
|
mpi_size_t qsize, rsize;
|
|
mpi_size_t sign_remainder = num->sign;
|
|
mpi_size_t sign_quotient = num->sign ^ den->sign;
|
|
unsigned int normalization_steps;
|
|
mpi_limb_t q_limb;
|
|
mpi_ptr_t marker[5];
|
|
int markidx = 0;
|
|
|
|
/* Ensure space is enough for quotient and remainder.
|
|
* We need space for an extra limb in the remainder, because it's
|
|
* up-shifted (normalized) below.
|
|
*/
|
|
rsize = nsize + 1;
|
|
mpi_resize(rem, rsize);
|
|
|
|
qsize = rsize - dsize; /* qsize cannot be bigger than this. */
|
|
if (qsize <= 0) {
|
|
if (num != rem) {
|
|
rem->nlimbs = num->nlimbs;
|
|
rem->sign = num->sign;
|
|
MPN_COPY(rem->d, num->d, nsize);
|
|
}
|
|
if (quot) {
|
|
/* This needs to follow the assignment to rem, in case the
|
|
* numerator and quotient are the same.
|
|
*/
|
|
quot->nlimbs = 0;
|
|
quot->sign = 0;
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (quot)
|
|
mpi_resize(quot, qsize);
|
|
|
|
/* Read pointers here, when reallocation is finished. */
|
|
np = num->d;
|
|
dp = den->d;
|
|
rp = rem->d;
|
|
|
|
/* Optimize division by a single-limb divisor. */
|
|
if (dsize == 1) {
|
|
mpi_limb_t rlimb;
|
|
if (quot) {
|
|
qp = quot->d;
|
|
rlimb = mpihelp_divmod_1(qp, np, nsize, dp[0]);
|
|
qsize -= qp[qsize - 1] == 0;
|
|
quot->nlimbs = qsize;
|
|
quot->sign = sign_quotient;
|
|
} else
|
|
rlimb = mpihelp_mod_1(np, nsize, dp[0]);
|
|
rp[0] = rlimb;
|
|
rsize = rlimb != 0?1:0;
|
|
rem->nlimbs = rsize;
|
|
rem->sign = sign_remainder;
|
|
return;
|
|
}
|
|
|
|
|
|
if (quot) {
|
|
qp = quot->d;
|
|
/* Make sure QP and NP point to different objects. Otherwise the
|
|
* numerator would be gradually overwritten by the quotient limbs.
|
|
*/
|
|
if (qp == np) { /* Copy NP object to temporary space. */
|
|
np = marker[markidx++] = mpi_alloc_limb_space(nsize);
|
|
MPN_COPY(np, qp, nsize);
|
|
}
|
|
} else /* Put quotient at top of remainder. */
|
|
qp = rp + dsize;
|
|
|
|
normalization_steps = count_leading_zeros(dp[dsize - 1]);
|
|
|
|
/* Normalize the denominator, i.e. make its most significant bit set by
|
|
* shifting it NORMALIZATION_STEPS bits to the left. Also shift the
|
|
* numerator the same number of steps (to keep the quotient the same!).
|
|
*/
|
|
if (normalization_steps) {
|
|
mpi_ptr_t tp;
|
|
mpi_limb_t nlimb;
|
|
|
|
/* Shift up the denominator setting the most significant bit of
|
|
* the most significant word. Use temporary storage not to clobber
|
|
* the original contents of the denominator.
|
|
*/
|
|
tp = marker[markidx++] = mpi_alloc_limb_space(dsize);
|
|
mpihelp_lshift(tp, dp, dsize, normalization_steps);
|
|
dp = tp;
|
|
|
|
/* Shift up the numerator, possibly introducing a new most
|
|
* significant word. Move the shifted numerator in the remainder
|
|
* meanwhile.
|
|
*/
|
|
nlimb = mpihelp_lshift(rp, np, nsize, normalization_steps);
|
|
if (nlimb) {
|
|
rp[nsize] = nlimb;
|
|
rsize = nsize + 1;
|
|
} else
|
|
rsize = nsize;
|
|
} else {
|
|
/* The denominator is already normalized, as required. Copy it to
|
|
* temporary space if it overlaps with the quotient or remainder.
|
|
*/
|
|
if (dp == rp || (quot && (dp == qp))) {
|
|
mpi_ptr_t tp;
|
|
|
|
tp = marker[markidx++] = mpi_alloc_limb_space(dsize);
|
|
MPN_COPY(tp, dp, dsize);
|
|
dp = tp;
|
|
}
|
|
|
|
/* Move the numerator to the remainder. */
|
|
if (rp != np)
|
|
MPN_COPY(rp, np, nsize);
|
|
|
|
rsize = nsize;
|
|
}
|
|
|
|
q_limb = mpihelp_divrem(qp, 0, rp, rsize, dp, dsize);
|
|
|
|
if (quot) {
|
|
qsize = rsize - dsize;
|
|
if (q_limb) {
|
|
qp[qsize] = q_limb;
|
|
qsize += 1;
|
|
}
|
|
|
|
quot->nlimbs = qsize;
|
|
quot->sign = sign_quotient;
|
|
}
|
|
|
|
rsize = dsize;
|
|
MPN_NORMALIZE(rp, rsize);
|
|
|
|
if (normalization_steps && rsize) {
|
|
mpihelp_rshift(rp, rp, rsize, normalization_steps);
|
|
rsize -= rp[rsize - 1] == 0?1:0;
|
|
}
|
|
|
|
rem->nlimbs = rsize;
|
|
rem->sign = sign_remainder;
|
|
while (markidx) {
|
|
markidx--;
|
|
mpi_free_limb_space(marker[markidx]);
|
|
}
|
|
}
|