rcore-tutorial/user/src/bin/peterson.rs

78 lines
No EOL
1.9 KiB
Rust

#![no_std]
#![no_main]
#![feature(core_intrinsics)]
#![feature(asm)]
#[macro_use]
extern crate user_lib;
extern crate alloc;
extern crate core;
use user_lib::{thread_create, waittid, exit, sleep};
use core::sync::atomic::{AtomicUsize, Ordering};
use alloc::vec::Vec;
const N: usize = 3;
static mut TURN: usize = 0;
static mut FLAG: [bool; 2] = [false; 2];
static GUARD: AtomicUsize = AtomicUsize::new(0);
fn critical_test_enter() {
assert_eq!(GUARD.fetch_add(1, Ordering::SeqCst), 0);
}
fn critical_test_claim() {
assert_eq!(GUARD.load(Ordering::SeqCst), 1);
}
fn critical_test_exit() {
assert_eq!(GUARD.fetch_sub(1, Ordering::SeqCst), 1);
}
fn peterson_enter_critical(id: usize, peer_id: usize) {
println!("Thread[{}] try enter", id);
vstore!(&FLAG[id], true);
vstore!(&TURN, peer_id);
memory_fence!();
while vload!(&FLAG[peer_id]) && vload!(&TURN) == peer_id {
println!("Thread[{}] enter fail", id);
sleep(1);
println!("Thread[{}] retry enter", id);
}
println!("Thread[{}] enter", id);
}
fn peterson_exit_critical(id: usize) {
vstore!(&FLAG[id], false);
println!("Thread[{}] exit", id);
}
pub fn thread_fn(id: usize) -> ! {
println!("Thread[{}] init.", id);
let peer_id: usize = id ^ 1;
for _ in 0..N {
peterson_enter_critical(id, peer_id);
critical_test_enter();
for _ in 0..3 {
critical_test_claim();
sleep(2);
}
critical_test_exit();
peterson_exit_critical(id);
}
exit(0)
}
#[no_mangle]
pub fn main() -> i32 {
let mut v = Vec::new();
v.push(thread_create(thread_fn as usize, 0));
// v.push(thread_create(thread_fn as usize, 1));
for tid in v.iter() {
let exit_code = waittid(*tid as usize);
assert_eq!(exit_code, 0, "thread conflict happened!");
println!("thread#{} exited with code {}", tid, exit_code);
}
println!("main thread exited.");
0
}