h2-mod/deps/libtommath/mp_signed_rsh.c

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2024-03-07 03:33:59 -05:00
#include "tommath_private.h"
#ifdef MP_SIGNED_RSH_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* shift right by a certain bit count with sign extension */
mp_err mp_signed_rsh(const mp_int *a, int b, mp_int *c)
{
mp_err err;
if (!mp_isneg(a)) {
return mp_div_2d(a, b, c, NULL);
}
if ((err = mp_add_d(a, 1uL, c)) != MP_OKAY) {
return err;
}
err = mp_div_2d(c, b, c, NULL);
return (err == MP_OKAY) ? mp_sub_d(c, 1uL, c) : err;
}
#endif