/*
* TEE_BigIntExtendedGcd
*/
void TEE_BigIntComputeExtendedGcd(TEE_BigInt *gcd, TEE_BigInt *u,
TEE_BigInt *v, const TEE_BigInt *op1,
const TEE_BigInt *op2)
{
mpanum mpa_gcd_res = (mpa_num_base *)gcd;
mpanum mpa_u = (mpa_num_base *)u;
mpanum mpa_v = (mpa_num_base *)v;
mpanum mpa_op1 = (mpa_num_base *)op1;
mpanum mpa_op2 = (mpa_num_base *)op2;
mpa_extended_gcd(mpa_gcd_res, mpa_u, mpa_v, mpa_op1, mpa_op2, mempool);
}
/*------------------------------------------------------------
*
* mpa_inv_mod
*
*/
int mpa_inv_mod(mpanum dest,
const mpanum op, const mpanum n, mpa_scratch_mem pool)
{
mpanum gcd;
mpanum tmp_dest;
int mem_marker;
int res;
if (mpa_cmp_short(op, 1) == 0) {
mpa_set_S32(dest, 1);
return 0;
}
mem_marker = (dest == op);
if (mem_marker)
mpa_alloc_static_temp_var(&tmp_dest, pool);
else
tmp_dest = dest;
mpa_alloc_static_temp_var(&gcd, pool);
/* The function mpa_extended_gcd behaves badly if tmp_dest = op */
mpa_extended_gcd(gcd, tmp_dest, NULL, op, n, pool);
res = mpa_cmp_short(gcd, 1);
if (mem_marker) {
mpa_copy(dest, tmp_dest);
mpa_free_static_temp_var(&tmp_dest, pool);
}
mpa_free_static_temp_var(&gcd, pool);
if (res == 0) {
while (mpa_cmp_short(dest, 0) < 0)
mpa_add(dest, dest, n, pool);
return 0;
} else {
return -1;
}
}
