docs: working selfhosted example

Signed-off-by: Henry Gressmann <mail@henrygressmann.de>

1 files changed, 19 insertions, 28 deletions

diff --git a/examples/rust/src/tinywasm.rs b/examples/rust/src/tinywasm.rs
index 4edde66..52af7b9 100644
--- a/examples/rust/src/tinywasm.rs
+++ b/examples/rust/src/tinywasm.rs
@@ -1,41 +1,32 @@
-#![no_std]
 #![no_main]
+use tinywasm::{Extern, FuncContext};
 
-use embedded_alloc::Heap;
-// use tinywasm::{Extern, FuncContext};
-
-#[cfg(not(test))]
-#[panic_handler]
-fn panic(_info: &core::panic::PanicInfo) -> ! {
-    core::arch::wasm32::unreachable()
+#[link(wasm_import_module = "env")]
+extern "C" {
+    fn printi32(x: i32);
 }
 
-#[global_allocator]
-static HEAP: Heap = Heap::empty();
-
 #[no_mangle]
-pub unsafe extern "C" fn _start() {
-    // Initialize the allocator BEFORE you use it
-    {
-        use core::mem::MaybeUninit;
-        const HEAP_SIZE: usize = 1024;
-        static mut HEAP_MEM: [MaybeUninit<u8>; HEAP_SIZE] = [MaybeUninit::uninit(); HEAP_SIZE];
-        unsafe { HEAP.init(HEAP_MEM.as_ptr() as usize, HEAP_SIZE) }
-    }
-
-    // now the allocator is ready types like Box, Vec can be used.
+pub extern "C" fn hello() {
     let _ = run();
 }
 
 fn run() -> tinywasm::Result<()> {
-    // let module = tinywasm::Module::parse_bytes(include_bytes!("../out/hello.wasm"))?;
-    // let mut store = tinywasm::Store::default();
+    let module = tinywasm::Module::parse_bytes(include_bytes!("../../wasm/hello.wasm"))?;
+    let mut store = tinywasm::Store::default();
+    let mut imports = tinywasm::Imports::new();
 
-    // let mut imports = tinywasm::Imports::new();
-    // imports.define("env", "printi32", Extern::typed_func(|_: FuncContext<'_>, _: i32| Ok(())))?;
+    imports.define(
+        "env",
+        "printi32",
+        Extern::typed_func(|_: FuncContext<'_>, v: i32| {
+            unsafe { printi32(v) }
+            Ok(())
+        }),
+    )?;
+    let instance = module.instantiate(&mut store, Some(imports))?;
 
-    // let instance = module.instantiate(&mut store, Some(imports))?;
-    // let add_and_print = instance.typed_func::<(i32, i32), ()>(&mut store, "add_and_print")?;
-    // add_and_print.call(&mut store, (1, 2))?;
+    let add_and_print = instance.typed_func::<(i32, i32), ()>(&mut store, "add_and_print")?;
+    add_and_print.call(&mut store, (1, 2))?;
     Ok(())
 }