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Sub.s
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Sub.s
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/* The MIT License (MIT)
*
* Copyright (c) 2015 mehdi sotoodeh
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
.include "defines.inc"
/* _______________________________________________________________________
/*
/* Z = X - Y
/* U64 ecp_Sub(U64* Z, const U64* X, const U64* Y)
/* _______________________________________________________________________ */
PUBPROC ecp_Sub
.equ Z, ARG1
.equ X, ARG2
.equ Y, ARG3M
SaveArg3
LOADA X
SUBA 24(Y),16(Y),8(Y),(Y)
SBB ACL,ACL
STOREA Z
RestoreArg3
ret
/* _______________________________________________________________________
/*
/* Z = X - Y
/* void ecp_SubReduce(U64* Z, const U64* X, const U64* Y)
/* _______________________________________________________________________ */
PUBPROC ecp_SubReduce
SaveArg3
LOADA X
SUBA 24(Y),16(Y),8(Y),(Y)
sbb ACL,ACL
and $38,ACL
SUBA $0,$0,$0,ACL
sbb ACL,ACL
and $38,ACL
SUBA $0,$0,$0,ACL
STOREA Z
RestoreArg3
ret
/* _______________________________________________________________________
/*
/* void ecp_Mod(U64* X)
/* Constant-time
/* _______________________________________________________________________ */
PUBPROC ecp_Mod
.equ X, ARG1
push C1
or $-1,C1
LOADA X
mov C1,ACH
mov $-19,ACL
shr $1,ACH
SUBA ACH,C1,C1,ACL
/* Undo SUB if CF=1 */
sbb C1,C1 # 0 or -1
and C1,ACH # 0 or 07fffffffffffffffh
and C1,ACL # 0 or -19
ADDA ACH,C1,C1,ACL
/* There could be second P there */
or $-1,C1
mov C1,ACH
mov $-19,ACL
shr $1,ACH
SUBA ACH,C1,C1,ACL
/* Undo SUB if CF=1 */
sbb C1,C1 # 0 or -1
and C1,ACH # 0 or 07fffffffffffffffh
and C1,ACL # 0 or -19
ADDA ACH,C1,C1,ACL
STOREA X
pop C1
ret
/* _______________________________________________________________________
/*
/* compare X and Y, return non-zero if X<Y, else 0
/* int ecp_CmpLT(const U64* X, const U64* Y)
/* _______________________________________________________________________ */
PUBPROC ecp_CmpLT
.equ X, ARG1
.equ Y, ARG2
LOADA X
SUBA 24(Y),16(Y),8(Y),(Y)
SBB ACL,ACL
ret
/* _______________________________________________________________________
/*
/* compare X and Y, return non-zero if X != Y, else 0
/* int ecp_CmpNE(const U64* X, const U64* Y)
/* _______________________________________________________________________ */
PUBPROC ecp_CmpNE
.equ X, ARG1
.equ Y, ARG2
mov 24(X),ACL
mov 16(X),A2
xor 24(Y),ACL
xor 16(Y),A2
mov 8(X),A1
or A2,ACL
xor 8(Y),A1
mov (X),A0
or A1,ACL
xor (Y),A0
or A0,ACL
ret