22 releases
0.2.0 | Mar 29, 2019 |
---|---|
0.1.7 | Mar 14, 2019 |
0.0.13 | Mar 7, 2019 |
0.0.2 | Feb 9, 2019 |
30 downloads per month
Used in 2 crates
47KB
1.5K
SLoC
Wasmly
This is a minimalistic web assembly tool for creating modules from arrays of bytes. This helps you develop much more closer to how web assembly apps exist at a low level.
If you check this project out and just want to get the dependencies to setup:
make setup
Go into any example directory:
make
make serve
Then open a browser to http://localhost:9999
Check the console for output!
If you are using this as a npm module
npm install wasmly
Very Simple Modules
If all you are doing is writing a single exported "main" function that takes in inputs, returns an output, and exposes "memory". Try this to save boiler plate:
var fs = require('fs');
let {makeSimple,int,I32,I32_CONST,END} = require("wasmly");
// main() -> i32
app = makeSimple([],[I32],[
vec([]), // no local variables
I32_CONST, int(42), // return 42
END
])
fs.writeFileSync('out.wasm',Buffer.from(app))
Simplest Module Possible
If you are trying to create the most simplest module from scratch. This has no functions
var fs = require('fs');
let {flatten,MAGIC_NUMBER,VERSION_1} = require("wasmly");
app = [
MAGIC_NUMBER,
VERSION_1,
]
// this is just a nested array of bytes:
// [[[0, 97, 115, 109]][[1, 0, 0, 0]]]
fs.writeFileSync('out.wasm',Buffer.from(flatten(app)))
Not very useful!
main()
From Scratch
...
// main() -> i32 { return 42 }
main_function_signature = [FUNC,vec([]),vec([I32])] // function signature returns 42
main_function_code = bytevec([
vec([]), // no local variables
[I32_CONST, int(42)], // return 42
END
])
//lets make memory at least 2 pages and at most 10 pages long
memory = [LIMIT_MIN_MAX,uint(2),uint(10)]
// put it all together as a module
app = [
MAGIC_NUMBER,
VERSION_1,
[SECTION_TYPE,bytevec(vec([main_function_signature]))],
[SECTION_FUNCTION,bytevec(vec([int(0)]))],
[SECTION_MEMORY,bytevec(vec([memory]))],
[SECTION_EXPORT,bytevec(vec([
[str("main"),DESC_FUNCTION,0],
[str("memory"),DESC_MEMORY,0]
]))],
[SECTION_CODE,bytevec(vec([main_function_code]))]
]
...
Memory Allocator
Let's make a very simple memory allocator.
...
// malloc(length:i32) -> i32 { ... }
malloc_function_signature = [FUNC,vec([I32]),vec([I32])] // function signature returns 42
malloc_function_code = bytevec([
vec([
[1, I32] // current_heap:i32
]),
// current_heap = global.heap
GLOBAL_GET, 0,
LOCAL_SET, 1,
// memorycurrent_heap = length
GLOBAL_GET, 0,
LOCAL_GET, 0,
I32_STORE, 0, 0,
// global.heap = current_heap + 1 + length
LOCAL_GET, 1,
I32_CONST, 1,
I32_ADD,
LOCAL_GET, 0,
I32_ADD,
GLOBAL_SET, 0,
// return current_heap + 1
LOCAL_GET, 1,
I32_CONST, 5,
I32_ADD,
END
])
// create a heap global set to zero
heap_global = [I32,MUTABLE,I32_CONST, int(0),END]
//lets make memory at least 2 pages and at most 10 pages long
memory = [LIMIT_MIN_MAX,uint(2),uint(10)]
// put it all together as a module
app = [
MAGIC_NUMBER,
VERSION_1,
[SECTION_TYPE,bytevec(vec([malloc_function_signature]))],
[SECTION_FUNCTION,bytevec(vec([0]))],
[SECTION_MEMORY,bytevec(vec([memory]))],
[SECTION_GLOBAL,bytevec(vec([heap_global]))],
[SECTION_EXPORT,bytevec(vec([
[str("malloc"),DESC_FUNCTION,0],
[str("memory"),DESC_MEMORY,0],
[str("heap"),DESC_GLOBAL,0]
]))],
[SECTION_CODE,bytevec(vec([malloc_function_code]))]
]
...