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Trivial ChaCha cleanups #2764

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Merged
merged 2 commits into from
Dec 5, 2023
Merged

Trivial ChaCha cleanups #2764

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e0480b5
Drop unnecessary SIMD subtraction in ChaCha20 `round`
TheBlueMatt Nov 30, 2023
c79cf82
Add inline suggestion tags to ChaCha20 SIMD wrappers
TheBlueMatt Nov 30, 2023
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38 changes: 19 additions & 19 deletions lightning/src/util/chacha20.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ mod real_chacha {
struct u32x4(pub u32, pub u32, pub u32, pub u32);
impl ::core::ops::Add for u32x4 {
type Output = u32x4;
#[inline]
fn add(self, rhs: u32x4) -> u32x4 {
u32x4(self.0.wrapping_add(rhs.0),
self.1.wrapping_add(rhs.1),
Expand All @@ -30,6 +31,7 @@ mod real_chacha {
}
impl ::core::ops::Sub for u32x4 {
type Output = u32x4;
#[inline]
fn sub(self, rhs: u32x4) -> u32x4 {
u32x4(self.0.wrapping_sub(rhs.0),
self.1.wrapping_sub(rhs.1),
Expand All @@ -39,23 +41,27 @@ mod real_chacha {
}
impl ::core::ops::BitXor for u32x4 {
type Output = u32x4;
#[inline]
fn bitxor(self, rhs: u32x4) -> u32x4 {
u32x4(self.0 ^ rhs.0, self.1 ^ rhs.1, self.2 ^ rhs.2, self.3 ^ rhs.3)
}
}
impl ::core::ops::Shr<u32x4> for u32x4 {
impl ::core::ops::Shr<u8> for u32x4 {
type Output = u32x4;
fn shr(self, rhs: u32x4) -> u32x4 {
u32x4(self.0 >> rhs.0, self.1 >> rhs.1, self.2 >> rhs.2, self.3 >> rhs.3)
#[inline]
fn shr(self, shr: u8) -> u32x4 {
u32x4(self.0 >> shr, self.1 >> shr, self.2 >> shr, self.3 >> shr)
}
}
impl ::core::ops::Shl<u32x4> for u32x4 {
impl ::core::ops::Shl<u8> for u32x4 {
type Output = u32x4;
fn shl(self, rhs: u32x4) -> u32x4 {
u32x4(self.0 << rhs.0, self.1 << rhs.1, self.2 << rhs.2, self.3 << rhs.3)
#[inline]
fn shl(self, shl: u8) -> u32x4 {
u32x4(self.0 << shl, self.1 << shl, self.2 << shl, self.3 << shl)
}
}
impl u32x4 {
#[inline]
fn from_bytes(bytes: &[u8]) -> Self {
assert_eq!(bytes.len(), 4*4);
Self (
Expand Down Expand Up @@ -118,31 +124,25 @@ mod real_chacha {
macro_rules! round{
($state: expr) => {{
$state.a = $state.a + $state.b;
rotate!($state.d, $state.a, S16);
rotate!($state.d, $state.a, 16);
$state.c = $state.c + $state.d;
rotate!($state.b, $state.c, S12);
rotate!($state.b, $state.c, 12);
$state.a = $state.a + $state.b;
rotate!($state.d, $state.a, S8);
rotate!($state.d, $state.a, 8);
$state.c = $state.c + $state.d;
rotate!($state.b, $state.c, S7);
rotate!($state.b, $state.c, 7);
}}
}

macro_rules! rotate {
($a: expr, $b: expr, $c:expr) => {{
($a: expr, $b: expr, $rot: expr) => {{
let v = $a ^ $b;
let r = S32 - $c;
let r = 32 - $rot;
let right = v >> r;
$a = (v << $c) ^ right
$a = (v << $rot) ^ right
}}
}

const S32:u32x4 = u32x4(32, 32, 32, 32);
const S16:u32x4 = u32x4(16, 16, 16, 16);
const S12:u32x4 = u32x4(12, 12, 12, 12);
const S8:u32x4 = u32x4(8, 8, 8, 8);
const S7:u32x4 = u32x4(7, 7, 7, 7);

impl ChaCha20 {
pub fn new(key: &[u8], nonce: &[u8]) -> ChaCha20 {
assert!(key.len() == 16 || key.len() == 32);
Expand Down