From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- lib/mpi/mpi-mul.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) create mode 100644 lib/mpi/mpi-mul.c (limited to 'lib/mpi/mpi-mul.c') diff --git a/lib/mpi/mpi-mul.c b/lib/mpi/mpi-mul.c new file mode 100644 index 000000000..7f4eda856 --- /dev/null +++ b/lib/mpi/mpi-mul.c @@ -0,0 +1,92 @@ +/* mpi-mul.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" + +void mpi_mul(MPI w, MPI u, MPI v) +{ + mpi_size_t usize, vsize, wsize; + mpi_ptr_t up, vp, wp; + mpi_limb_t cy; + int usign, vsign, sign_product; + int assign_wp = 0; + mpi_ptr_t tmp_limb = NULL; + + if (u->nlimbs < v->nlimbs) { + /* Swap U and V. */ + usize = v->nlimbs; + usign = v->sign; + up = v->d; + vsize = u->nlimbs; + vsign = u->sign; + vp = u->d; + } else { + usize = u->nlimbs; + usign = u->sign; + up = u->d; + vsize = v->nlimbs; + vsign = v->sign; + vp = v->d; + } + sign_product = usign ^ vsign; + wp = w->d; + + /* Ensure W has space enough to store the result. */ + wsize = usize + vsize; + if (w->alloced < wsize) { + if (wp == up || wp == vp) { + wp = mpi_alloc_limb_space(wsize); + assign_wp = 1; + } else { + mpi_resize(w, wsize); + wp = w->d; + } + } else { /* Make U and V not overlap with W. */ + if (wp == up) { + /* W and U are identical. Allocate temporary space for U. */ + up = tmp_limb = mpi_alloc_limb_space(usize); + /* Is V identical too? Keep it identical with U. */ + if (wp == vp) + vp = up; + /* Copy to the temporary space. */ + MPN_COPY(up, wp, usize); + } else if (wp == vp) { + /* W and V are identical. Allocate temporary space for V. */ + vp = tmp_limb = mpi_alloc_limb_space(vsize); + /* Copy to the temporary space. */ + MPN_COPY(vp, wp, vsize); + } + } + + if (!vsize) + wsize = 0; + else { + mpihelp_mul(wp, up, usize, vp, vsize, &cy); + wsize -= cy ? 0:1; + } + + if (assign_wp) + mpi_assign_limb_space(w, wp, wsize); + w->nlimbs = wsize; + w->sign = sign_product; + if (tmp_limb) + mpi_free_limb_space(tmp_limb); +} +EXPORT_SYMBOL_GPL(mpi_mul); + +void mpi_mulm(MPI w, MPI u, MPI v, MPI m) +{ + mpi_mul(w, u, v); + mpi_tdiv_r(w, w, m); +} +EXPORT_SYMBOL_GPL(mpi_mulm); -- cgit v1.2.3