| // Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| #![feature(asm)] |
| |
| #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] |
| fn read(ptr: &u32) -> u32 { |
| let out: u32; |
| unsafe { |
| asm!("mov $1, $0" : "=r" (out) : "*m" (ptr)); |
| } |
| out |
| } |
| |
| #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] |
| fn write(ptr: &mut u32, val: u32) { |
| unsafe { |
| asm!("mov $1, $0" : "=*m" (ptr) : "r" (val)); |
| } |
| } |
| |
| #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] |
| fn replace(ptr: &mut u32, val: u32) -> u32 { |
| let out: u32; |
| unsafe { |
| asm!("mov $0, $1; mov $2, $0" : "+*m" (ptr), "=&r" (out) : "r" (val)); |
| } |
| out |
| } |
| |
| #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] |
| pub fn main() { |
| let a = 1; |
| assert_eq!(read(&a), 1); |
| let mut b = 2; |
| write(&mut b, 3); |
| assert_eq!(b, 3); |
| let mut c = 4; |
| assert_eq!(replace(&mut c, 5), 4); |
| assert_eq!(c, 5); |
| } |
| |
| #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))] |
| pub fn main() {} |