tls: P256: change logic so that we don't need double-wide vectors everywhere

Change sp_256to512z_mont_{mul,sqr}_8 to not require/zero upper 256 bits.
There is only one place where we actually used that (and that's why there
used to be zeroing memset of top half!). Fix up that place.
As a bonus, 256x256->512 multiply no longer needs to care for
"r overlaps a or b" case.

This shrinks sp_point structure as well, not just temporaries.

function                                             old     new   delta
sp_256to512z_mont_mul_8                              150       -    -150
sp_256_mont_mul_8                                      -     147    +147
sp_256to512z_mont_sqr_8                                7       -      -7
sp_256_mont_sqr_8                                      -       7      +7
sp_256_ecc_mulmod_8                                  494     543     +49
sp_512to256_mont_reduce_8                            243     249      +6
sp_256_point_from_bin2x32                             73      70      -3
sp_256_proj_point_dbl_8                              353     345      -8
sp_256_proj_point_add_8                              544     499     -45
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 2/3 up/down: 209/-213)           Total: -4 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

0 files changed, 0 insertions, 0 deletions