46 lines
985 B
Rust
46 lines
985 B
Rust
|
#![no_std]
|
||
|
|
|
||
|
|
use core::cell::UnsafeCell;
|
||
|
|
use core::panic::PanicInfo;
|
||
|
|
|
||
|
|
// --- bump allocator ---
|
||
|
|
const HEAP_SIZE: usize = 65536;
|
||
|
|
|
||
|
|
struct BumpAlloc {
|
||
|
|
heap: UnsafeCell<[u8; HEAP_SIZE]>,
|
||
|
|
offset: UnsafeCell<usize>,
|
||
|
|
}
|
||
|
|
|
||
|
|
unsafe impl Sync for BumpAlloc {}
|
||
|
|
|
||
|
|
static ALLOC: BumpAlloc = BumpAlloc {
|
||
|
|
heap: UnsafeCell::new([0u8; HEAP_SIZE]),
|
||
|
|
offset: UnsafeCell::new(0),
|
||
|
|
};
|
||
|
|
|
||
|
|
#[unsafe(no_mangle)]
|
||
|
|
pub extern "C" fn alloc(size: i32) -> i32 {
|
||
|
|
unsafe {
|
||
|
|
let offset = &mut *ALLOC.offset.get();
|
||
|
|
let heap = &mut *ALLOC.heap.get();
|
||
|
|
let align = 8;
|
||
|
|
let start = (*offset + align - 1) & !(align - 1);
|
||
|
|
let end = start + size as usize;
|
||
|
|
if end > heap.len() {
|
||
|
|
return 0; // OOM
|
||
|
|
}
|
||
|
|
*offset = end;
|
||
|
|
heap.as_ptr().add(start) as i32
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#[unsafe(no_mangle)]
|
||
|
|
pub extern "C" fn handle(_ptr: i32, _len: i32) {
|
||
|
|
// Silent: receive bytes, do nothing
|
||
|
|
}
|
||
|
|
|
||
|
|
#[panic_handler]
|
||
|
|
fn panic(_info: &PanicInfo) -> ! {
|
||
|
|
loop {}
|
||
|
|
}
|