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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
// ----------------------------------------------------------------------------
// Add, z := x + y
// Inputs x[m], y[n]; outputs function return (carry-out) and z[p]
//
// extern uint64_t bignum_add(uint64_t p, uint64_t *z, uint64_t m,
// const uint64_t *x, uint64_t n, const uint64_t *y);
//
// Does the z := x + y operation, truncating modulo p words in general and
// returning a top carry (0 or 1) in the p'th place, only adding the input
// words below p (as well as m and n respectively) to get the sum and carry.
//
// Standard ARM ABI: X0 = p, X1 = z, X2 = m, X3 = x, X4 = n, X5 = y, returns X0
// ----------------------------------------------------------------------------
macro_rules! p {
() => {
"x0"
};
}
macro_rules! z {
() => {
"x1"
};
}
macro_rules! m {
() => {
"x2"
};
}
macro_rules! x {
() => {
"x3"
};
}
macro_rules! n {
() => {
"x4"
};
}
macro_rules! y {
() => {
"x5"
};
}
macro_rules! i {
() => {
"x6"
};
}
macro_rules! a {
() => {
"x7"
};
}
macro_rules! d {
() => {
"x8"
};
}
/// Add, z := x + y
///
/// Inputs x[m], y[n]; outputs function return (carry-out) and z[p]
///
/// Does the z := x + y operation, truncating modulo p words in general and
/// returning a top carry (0 or 1) in the p'th place, only adding the input
/// words below p (as well as m and n respectively) to get the sum and carry.
pub(crate) fn bignum_add(z: &mut [u64], x: &[u64], y: &[u64]) -> u64 {
let ret: u64;
// SAFETY: inline assembly. see [crate::low::inline_assembly_safety] for safety info.
unsafe {
core::arch::asm!(
// First clamp the two input sizes m := min(p,m) and n := min(p,n) since
// we'll never need words past the p'th. Can now assume m <= p and n <= p.
// Then compare the modified m and n and branch accordingly
Q!(" cmp " m!() ", " p!()),
Q!(" csel " m!() ", " p!() ", " m!() ", cs"),
Q!(" cmp " n!() ", " p!()),
Q!(" csel " n!() ", " p!() ", " n!() ", cs"),
Q!(" cmp " m!() ", " n!()),
Q!(" bcc " Label!("bignum_add_ylonger", 2, After)),
// The case where x is longer or of the same size (p >= m >= n)
Q!(" sub " p!() ", " p!() ", " m!()),
Q!(" sub " m!() ", " m!() ", " n!()),
Q!(" ands " i!() ", xzr, xzr"),
Q!(" cbz " n!() ", " Label!("bignum_add_xmainskip", 3, After)),
Q!(Label!("bignum_add_xmainloop", 4) ":"),
Q!(" ldr " a!() ", [" x!() ", " i!() ", lsl #3]"),
Q!(" ldr " d!() ", [" y!() ", " i!() ", lsl #3]"),
Q!(" adcs " a!() ", " a!() ", " d!()),
Q!(" str " a!() ", [" z!() ", " i!() ", lsl #3]"),
Q!(" add " i!() ", " i!() ", #1"),
Q!(" sub " n!() ", " n!() ", #1"),
Q!(" cbnz " n!() ", " Label!("bignum_add_xmainloop", 4, Before)),
Q!(Label!("bignum_add_xmainskip", 3) ":"),
Q!(" cbz " m!() ", " Label!("bignum_add_xtopskip", 5, After)),
Q!(Label!("bignum_add_xtoploop", 6) ":"),
Q!(" ldr " a!() ", [" x!() ", " i!() ", lsl #3]"),
Q!(" adcs " a!() ", " a!() ", xzr"),
Q!(" str " a!() ", [" z!() ", " i!() ", lsl #3]"),
Q!(" add " i!() ", " i!() ", #1"),
Q!(" sub " m!() ", " m!() ", #1"),
Q!(" cbnz " m!() ", " Label!("bignum_add_xtoploop", 6, Before)),
Q!(Label!("bignum_add_xtopskip", 5) ":"),
Q!(" cbnz " p!() ", " Label!("bignum_add_tails", 7, After)),
Q!(" cset " "x0, cs"),
// linear hoisting in -> ret after bignum_add_tail
Q!(" b " Label!("hoist_finish", 8, After)),
// The case where y is longer (p >= n > m)
Q!(Label!("bignum_add_ylonger", 2) ":"),
Q!(" sub " p!() ", " p!() ", " n!()),
Q!(" sub " n!() ", " n!() ", " m!()),
Q!(" ands " i!() ", xzr, xzr"),
Q!(" cbz " m!() ", " Label!("bignum_add_ytoploop", 9, After)),
Q!(Label!("bignum_add_ymainloop", 12) ":"),
Q!(" ldr " a!() ", [" x!() ", " i!() ", lsl #3]"),
Q!(" ldr " d!() ", [" y!() ", " i!() ", lsl #3]"),
Q!(" adcs " a!() ", " a!() ", " d!()),
Q!(" str " a!() ", [" z!() ", " i!() ", lsl #3]"),
Q!(" add " i!() ", " i!() ", #1"),
Q!(" sub " m!() ", " m!() ", #1"),
Q!(" cbnz " m!() ", " Label!("bignum_add_ymainloop", 12, Before)),
Q!(Label!("bignum_add_ytoploop", 9) ":"),
Q!(" ldr " a!() ", [" y!() ", " i!() ", lsl #3]"),
Q!(" adcs " a!() ", xzr, " a!()),
Q!(" str " a!() ", [" z!() ", " i!() ", lsl #3]"),
Q!(" add " i!() ", " i!() ", #1"),
Q!(" sub " n!() ", " n!() ", #1"),
Q!(" cbnz " n!() ", " Label!("bignum_add_ytoploop", 9, Before)),
Q!(Label!("bignum_add_ytopskip", 13) ":"),
Q!(" cbnz " p!() ", " Label!("bignum_add_tails", 7, After)),
Q!(" cset " "x0, cs"),
Q!(" b " Label!("hoist_finish", 8, After)),
// Adding a non-trivial tail, when p > max(m,n)
Q!(Label!("bignum_add_tails", 7) ":"),
Q!(" cset " a!() ", cs"),
Q!(" str " a!() ", [" z!() ", " i!() ", lsl #3]"),
Q!(" b " Label!("bignum_add_tail", 14, After)),
Q!(Label!("bignum_add_tailloop", 15) ":"),
Q!(" str " "xzr, [" z!() ", " i!() ", lsl #3]"),
Q!(Label!("bignum_add_tail", 14) ":"),
Q!(" add " i!() ", " i!() ", #1"),
Q!(" sub " p!() ", " p!() ", #1"),
Q!(" cbnz " p!() ", " Label!("bignum_add_tailloop", 15, Before)),
Q!(" mov " "x0, xzr"),
Q!(Label!("hoist_finish", 8) ":"),
inout("x0") z.len() => ret,
inout("x1") z.as_mut_ptr() => _,
inout("x2") x.len() => _,
inout("x3") x.as_ptr() => _,
inout("x4") y.len() => _,
inout("x5") y.as_ptr() => _,
// clobbers
out("x6") _,
out("x7") _,
out("x8") _,
)
};
ret
}