Commit 8500c6e0 authored by Niels Möller's avatar Niels Möller

x86_64 assembly for ecc_256_redc.

parent 59eb1aa1
2013-03-06 Niels Möller <nisse@lysator.liu.se>
* x86_64/ecc-256-redc.asm: New file, 2.5 time speedup.
* x86_64/ecc-224-modp.asm: New file, 5 time speedup over C
version.
......
C nettle, low-level cryptographics library
C
C Copyright (C) 2013 Niels Möller
C
C The nettle library is free software; you can redistribute it and/or modify
C it under the terms of the GNU Lesser General Public License as published by
C the Free Software Foundation; either version 2.1 of the License, or (at your
C option) any later version.
C
C The nettle library is distributed in the hope that it will be useful, but
C WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
C or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
C License for more details.
C
C You should have received a copy of the GNU Lesser General Public License
C along with the nettle library; see the file COPYING.LIB. If not, write to
C the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
C MA 02111-1301, USA.
.file "ecc-256-redc.asm"
define(<RP>, <%rsi>)
define(<U0>, <%rdi>) C Overlaps unused ecc input
define(<U1>, <%rcx>)
define(<U2>, <%rax>)
define(<U3>, <%rdx>)
define(<U4>, <%r8>)
define(<U5>, <%r9>)
define(<U6>, <%r10>)
define(<F0>, <%r11>)
define(<F1>, <%r12>)
define(<F2>, <%rbx>)
define(<F3>, <%rbp>)
C FOLD(x), sets (F3,F2,F1,F0) <-- (x << 224) - (x << 128) - (x<<32)
define(<FOLD>, <
mov $1, F2
mov $1, F3
shl <$>32, F2
shr <$>32, F3
xor F0,F0
xor F1,F1
sub F2, F0
sbb F3, F1
sbb $1, F2
sbb <$>0, F3
>)
PROLOGUE(nettle_ecc_256_redc)
W64_ENTRY(2, 0)
C save all registers that need to be saved
push %rbx
push %rbp
push %r12
mov (RP), U0
FOLD(U0)
mov 8(RP), U1
mov 16(RP), U2
mov 24(RP), U3
sub F0, U1
sbb F1, U2
sbb F2, U3
sbb F3, U0 C Add in later
FOLD(U1)
mov 32(RP), U4
sub F0, U2
sbb F1, U3
sbb F2, U4
sbb F3, U1
FOLD(U2)
mov 40(RP), U5
sub F0, U3
sbb F1, U4
sbb F2, U5
sbb F3, U2
FOLD(U3)
mov 48(RP), U6
sub F0, U4
sbb F1, U5
sbb F2, U6
sbb F3, U3
add U4, U0
adc U5, U1
adc U6, U2
adc 56(RP), U3
C If carry, we need to add in
C 2^256 - p = <0xfffffffe, 0xff..ff, 0xffffffff00000000, 1>
sbb F2, F2
mov F2, F0
mov F2, F1
mov XREG(F2), XREG(F3)
neg F0
shl $32, F1
and $-2, XREG(F3)
add F0, U0
mov U0, (RP)
adc F1, U1
mov U1, 8(RP)
adc F2, U2
mov U2, 16(RP)
adc F3, U3
mov U3, 24(RP)
pop %r12
pop %rbp
pop %rbx
W64_EXIT(2, 0)
ret
EPILOGUE(nettle_ecc_256_redc)
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