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|
extern crate psm;
psm::psm_stack_manipulation! {
yes {
use std::alloc;
const STACK_ALIGN: usize = 4096;
const FRAME_SIZE: usize = 4096;
const FIB_COUNTS: [(usize, u64); 3] = [
(8, 21),
(16, 987),
(24, 46368),
];
#[inline(never)]
fn fib(n: usize) -> u64 {
unsafe {
let layout = alloc::Layout::from_size_align(FRAME_SIZE, STACK_ALIGN).unwrap();
let new_stack = alloc::alloc(layout);
assert!(!new_stack.is_null(), "allocations must succeed!");
let r = match n {
0 => 0,
1 => 1,
_ => {
psm::on_stack(new_stack, FRAME_SIZE, || {
fib(n - 1) + fib(n - 2)
})
}
};
alloc::dealloc(new_stack, layout);
r
}
}
fn main() {
for &(n, expected) in FIB_COUNTS.iter() {
let res = fib(n);
assert_eq!(res, expected);
println!("fib({}) = {}", n, res);
}
}
}
no {
fn main() {
eprintln!("Stack manipulation not supported by this target");
}
}
}
#[test]
fn run_example() {
main()
}
|
