zacheryasc
7ef7bd0b50
Crates continued to grow in number, but most are still quite small and feature specific. This refactor consolidates them.
62 lines
1.4 KiB
Rust
62 lines
1.4 KiB
Rust
#![no_std]
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use core::cell::UnsafeCell;
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use core::panic::PanicInfo;
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// --- bump allocator ---
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const HEAP_SIZE: usize = 65536;
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struct BumpAlloc {
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heap: UnsafeCell<[u8; HEAP_SIZE]>,
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offset: UnsafeCell<usize>,
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}
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unsafe impl Sync for BumpAlloc {}
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static ALLOC: BumpAlloc = BumpAlloc {
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heap: UnsafeCell::new([0u8; HEAP_SIZE]),
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offset: UnsafeCell::new(0),
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};
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#[unsafe(no_mangle)]
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pub extern "C" fn alloc(size: i32) -> i32 {
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unsafe {
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let offset = &mut *ALLOC.offset.get();
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let heap = &mut *ALLOC.heap.get();
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let align = 8;
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let start = (*offset + align - 1) & !(align - 1);
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let end = start + size as usize;
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if end > heap.len() {
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return 0; // OOM
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}
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*offset = end;
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heap.as_ptr().add(start) as i32
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}
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}
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// --- host import ---
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#[link(wasm_import_module = "swactor")]
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unsafe extern "C" {
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#[link_name = "send"]
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fn host_send(dest_ptr: i32, payload_ptr: i32, payload_len: i32);
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}
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/// Message format: first 32 bytes = destination address, rest = payload.
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/// Echo sends the payload portion back to the specified destination.
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#[unsafe(no_mangle)]
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pub extern "C" fn handle(ptr: i32, len: i32) {
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if len < 32 {
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return;
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}
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let dest_ptr = ptr;
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let payload_ptr = ptr + 32;
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let payload_len = len - 32;
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unsafe {
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host_send(dest_ptr, payload_ptr, payload_len);
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}
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}
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#[panic_handler]
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fn panic(_info: &PanicInfo) -> ! {
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loop {}
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}
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