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