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// 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
// ----------------------------------------------------------------------------
// Reduce modulo group order, z := x mod n_384
// Input x[6]; output z[6]
//
// extern void bignum_mod_n384_6(uint64_t z[static 6], const uint64_t x[static 6]);
//
// Reduction is modulo the group order of the NIST curve P-384.
//
// Standard x86-64 ABI: RDI = z, RSI = x
// Microsoft x64 ABI: RCX = z, RDX = x
// ----------------------------------------------------------------------------
macro_rules! z {
() => {
"rdi"
};
}
macro_rules! x {
() => {
"rsi"
};
}
macro_rules! d0 {
() => {
"rdx"
};
}
macro_rules! d1 {
() => {
"rcx"
};
}
macro_rules! d2 {
() => {
"r8"
};
}
macro_rules! d3 {
() => {
"r9"
};
}
macro_rules! d4 {
() => {
"r10"
};
}
macro_rules! d5 {
() => {
"r11"
};
}
macro_rules! a {
() => {
"rax"
};
}
// Re-use the input pointer as a temporary once we're done
macro_rules! c {
() => {
"rsi"
};
}
/// Reduce modulo group order, z := x mod n_384
///
/// Input x[6]; output z[6]
///
/// Reduction is modulo the group order of the NIST curve P-384.
pub(crate) fn bignum_mod_n384(z: &mut [u64; 6], x: &[u64; 6]) {
// SAFETY: inline assembly. see [crate::low::inline_assembly_safety] for safety info.
unsafe {
core::arch::asm!(
Q!(" endbr64 " ),
// Load the input and compute x + (2^384 - n_384)
Q!(" mov " a!() ", 0x1313e695333ad68d"),
Q!(" mov " d0!() ", [" x!() "]"),
Q!(" add " d0!() ", " a!()),
Q!(" mov " d1!() ", 0xa7e5f24db74f5885"),
Q!(" adc " d1!() ", [" x!() "+ 8]"),
Q!(" mov " d2!() ", 0x389cb27e0bc8d220"),
Q!(" adc " d2!() ", [" x!() "+ 16]"),
Q!(" mov " d3!() ", [" x!() "+ 24]"),
Q!(" adc " d3!() ", 0"),
Q!(" mov " d4!() ", [" x!() "+ 32]"),
Q!(" adc " d4!() ", 0"),
Q!(" mov " d5!() ", [" x!() "+ 40]"),
Q!(" adc " d5!() ", 0"),
// Now CF is set iff 2^384 <= x + (2^384 - n_384), i.e. iff n_384 <= x.
// Create a mask for the condition x < n. We now want to subtract the
// masked (2^384 - n_384), but because we're running out of registers
// without using a save-restore sequence, we need some contortions.
// Create the lowest digit (re-using a kept from above)
Q!(" sbb " c!() ", " c!()),
Q!(" not " c!()),
Q!(" and " a!() ", " c!()),
// Do the first digit of addition and writeback
Q!(" sub " d0!() ", " a!()),
Q!(" mov " "[" z!() "], " d0!()),
// Preserve carry chain and do the next digit
Q!(" sbb " d0!() ", " d0!()),
Q!(" mov " a!() ", 0xa7e5f24db74f5885"),
Q!(" and " a!() ", " c!()),
Q!(" neg " d0!()),
Q!(" sbb " d1!() ", " a!()),
Q!(" mov " "[" z!() "+ 8], " d1!()),
// Preserve carry chain once more and do remaining digits
Q!(" sbb " d0!() ", " d0!()),
Q!(" mov " a!() ", 0x389cb27e0bc8d220"),
Q!(" and " a!() ", " c!()),
Q!(" neg " d0!()),
Q!(" sbb " d2!() ", " a!()),
Q!(" mov " "[" z!() "+ 16], " d2!()),
Q!(" sbb " d3!() ", 0"),
Q!(" mov " "[" z!() "+ 24], " d3!()),
Q!(" sbb " d4!() ", 0"),
Q!(" mov " "[" z!() "+ 32], " d4!()),
Q!(" sbb " d5!() ", 0"),
Q!(" mov " "[" z!() "+ 40], " d5!()),
inout("rdi") z.as_mut_ptr() => _,
inout("rsi") x.as_ptr() => _,
// clobbers
out("r10") _,
out("r11") _,
out("r8") _,
out("r9") _,
out("rax") _,
out("rcx") _,
out("rdx") _,
)
};
}