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|
// Test that `extern "custom"` functions can be called from assembly, and defined using a naked
// function, and `global_asm!` with an `extern "custom"` block.
//
//@ run-pass
//@ only-x86_64
#![feature(abi_custom)]
use std::arch::{asm, global_asm, naked_asm};
#[unsafe(naked)]
unsafe extern "custom" fn double() {
naked_asm!("add rax, rax", "ret");
}
global_asm!(
// work around macOS prefixing symbols with _
" .globl {0}",
"{0}:",
" add rax, 1",
" ret",
sym increment,
);
unsafe extern "custom" {
fn increment();
}
#[repr(transparent)]
struct Thing(u64);
impl Thing {
#[unsafe(naked)]
unsafe extern "custom" fn is_even() {
naked_asm!("test al, 1", "sete al", "ret");
}
}
trait BitwiseNot {
#[unsafe(naked)]
unsafe extern "custom" fn bitwise_not() {
naked_asm!("not rax", "ret");
}
}
impl BitwiseNot for Thing {}
#[unsafe(naked)]
unsafe extern "C" fn const_generic<const N: u64>() {
naked_asm!(
"mov rax, {}",
"ret",
const N,
);
}
pub fn main() {
let mut x: u64 = 21;
unsafe { asm!("call {}", sym double, inout("rax") x) };
assert_eq!(x, 42);
let mut x: u64 = 41;
unsafe { asm!("call {}", sym increment, inout("rax") x) };
assert_eq!(x, 42);
let mut x: u8;
unsafe { asm!("call {}", sym Thing::is_even, inout("al") 42u8 => x) };
assert!(x != 0);
let mut x: u64 = 42;
unsafe { asm!("call {}", sym Thing::bitwise_not, inout("rax") x) };
assert_eq!(x, !42);
// Create and call in `asm!` an `extern "custom"` function pointer.
fn caller(f: unsafe extern "custom" fn(), mut x: u64) -> u64 {
unsafe { asm!("call {}", in(reg) f, inout("rax") x) };
x
}
assert_eq!(caller(double, 2), 4);
let x: u64;
unsafe { asm!("call {}", sym const_generic::<42>, out("rax") x) };
assert_eq!(x, 42);
let x: u64;
unsafe { asm!("call {}", sym const_generic::<84>, out("rax") x) };
assert_eq!(x, 84);
}
|
