1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
// generated source. do not edit.
#![allow(non_upper_case_globals, unused_macros, unused_imports)]
use crate::low::macros::*;
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0 OR ISC OR MIT-0
// ----------------------------------------------------------------------------
// Negate modulo p_384, z := (-x) mod p_384, assuming x reduced
// Input x[6]; output z[6]
//
// extern void bignum_neg_p384(uint64_t z[static 6], const uint64_t x[static 6]);
//
// Standard ARM ABI: X0 = z, X1 = x
// ----------------------------------------------------------------------------
macro_rules! z {
() => {
"x0"
};
}
macro_rules! x {
() => {
"x1"
};
}
macro_rules! p {
() => {
"x2"
};
}
macro_rules! t {
() => {
"x3"
};
}
macro_rules! d0 {
() => {
"x4"
};
}
macro_rules! d1 {
() => {
"x5"
};
}
macro_rules! d2 {
() => {
"x6"
};
}
macro_rules! d3 {
() => {
"x7"
};
}
macro_rules! d4 {
() => {
"x8"
};
}
macro_rules! d5 {
() => {
"x9"
};
}
/// Negate modulo p_384, z := (-x) mod p_384, assuming x reduced
///
/// Input x[6]; output z[6]
pub(crate) fn bignum_neg_p384(z: &mut [u64; 6], x: &[u64; 6]) {
// SAFETY: inline assembly. see [crate::low::inline_assembly_safety] for safety info.
unsafe {
core::arch::asm!(
// Load the 6 digits of x
Q!(" ldp " d0!() ", " d1!() ", [" x!() "]"),
Q!(" ldp " d2!() ", " d3!() ", [" x!() ", #16]"),
Q!(" ldp " d4!() ", " d5!() ", [" x!() ", #32]"),
// Set a bitmask p for the input being nonzero, so that we avoid doing
// -0 = p_384 and hence maintain strict modular reduction
Q!(" orr " p!() ", " d0!() ", " d1!()),
Q!(" orr " t!() ", " d2!() ", " d3!()),
Q!(" orr " p!() ", " p!() ", " t!()),
Q!(" orr " t!() ", " d4!() ", " d5!()),
Q!(" orr " p!() ", " p!() ", " t!()),
Q!(" cmp " p!() ", #0"),
Q!(" csetm " p!() ", ne"),
// Mask the complicated lower three words of p_384 = [-1;-1;-1;n2;n1;n0]
// and subtract, using mask itself for upper digits
Q!(" and " t!() ", " p!() ", #0x00000000ffffffff"),
Q!(" subs " d0!() ", " t!() ", " d0!()),
Q!(" and " t!() ", " p!() ", #0xffffffff00000000"),
Q!(" sbcs " d1!() ", " t!() ", " d1!()),
Q!(" and " t!() ", " p!() ", #0xfffffffffffffffe"),
Q!(" sbcs " d2!() ", " t!() ", " d2!()),
Q!(" sbcs " d3!() ", " p!() ", " d3!()),
Q!(" sbcs " d4!() ", " p!() ", " d4!()),
Q!(" sbc " d5!() ", " p!() ", " d5!()),
// Write back the result
Q!(" stp " d0!() ", " d1!() ", [" z!() "]"),
Q!(" stp " d2!() ", " d3!() ", [" z!() ", #16]"),
Q!(" stp " d4!() ", " d5!() ", [" z!() ", #32]"),
// Return
inout("x0") z.as_mut_ptr() => _,
inout("x1") x.as_ptr() => _,
// clobbers
out("x2") _,
out("x3") _,
out("x4") _,
out("x5") _,
out("x6") _,
out("x7") _,
out("x8") _,
out("x9") _,
)
};
}