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denoland-deno/core/examples/wasm.js
Divy Srivastava ca66978a5a
feat(ops): fast calls for Wasm (#16776)
This PR introduces Wasm ops. These calls are optimized for entry from
Wasm land.

The `#[op(wasm)]` attribute is opt-in. 

Last parameter `Option<&mut [u8]>` is the memory slice of the Wasm
module *when entered from a Fast API call*. Otherwise, the user is
expected to implement logic to obtain the memory if `None`

```rust
#[op(wasm)]
pub fn op_args_get(
  offset: i32,
  buffer_offset: i32,
  memory: Option<&mut [u8]>,
) {
  // ...
}
```
2022-11-27 19:24:28 +05:30

28 lines
1 KiB
JavaScript

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
// asc wasm.ts --exportStart --initialMemory 6400 -O -o wasm.wasm
// deno-fmt-ignore
const bytes = new Uint8Array([
0, 97, 115, 109, 1, 0, 0, 0, 1, 4, 1, 96, 0, 0, 2,
15, 1, 3, 111, 112, 115, 7, 111, 112, 95, 119, 97, 115, 109, 0,
0, 3, 3, 2, 0, 0, 5, 4, 1, 0, 128, 50, 7, 36, 4,
7, 111, 112, 95, 119, 97, 115, 109, 0, 0, 4, 99, 97, 108, 108,
0, 1, 6, 109, 101, 109, 111, 114, 121, 2, 0, 6, 95, 115, 116,
97, 114, 116, 0, 2, 10, 10, 2, 4, 0, 16, 0, 11, 3, 0,
1, 11
]);
const { ops } = Deno.core;
const module = new WebAssembly.Module(bytes);
const instance = new WebAssembly.Instance(module, { ops });
ops.op_set_wasm_mem(instance.exports.memory);
instance.exports.call();
const memory = instance.exports.memory;
const view = new Uint8Array(memory.buffer);
if (view[0] !== 69) {
throw new Error("Expected first byte to be 69");
}