asm.js是一个底层、格外为 JavaScript 子集优化的编译器。这是 Mozilla 研究项目，类似 Emscripten, Mandreel, 和 LLJS,这个示例让我们简单学习一下asm.js的使用
复制代码 代码如下:
function mymodule(global, foreign, buffer) {
"use asm";
// -------------------------------------------------------------------------
// SECTION 1: imports
var H32 = new global.Int32Array(buffer);
var HU32 = new global.Uint32Array(buffer);
var log = foreign.consoleDotLog;
// -------------------------------------------------------------------------
// SECTION 2: functions
function f(x, y, z, w) {
// SECTION A: parameter type declarations
x = x|0; // int parameter
y = +y; // double parameter
// SECTION B: function body
log(x|0); // call into FFI -- must force the sign
log(y); // call into FFI -- already know it's a double
x = (x+3)|0; // signed addition
// SECTION C: unconditional return
return ((((x+1)|0)>>>0)/(x|0))>>>0; // compound expression
}
function g() {
g_f = +g_i; // read/write globals
return;
}
function g2() {
return;
}
function h(i, x) {
i = i|0;
x = x|0;
H32[(i&0xffffffff)>>4] = x; // masked by 2^k-1, shifted by byte count
ftable_2[(x-2)&2](); // dynamic call of functions in table 2
}
// -------------------------------------------------------------------------
// SECTION 3: function tables
var ftable_1 = [f];
var ftable_2 = [g, g2]; // all of the same type
// -------------------------------------------------------------------------
// SECTION 4: globals
var g_i = 0; // int global
var g_f = 0.0; // double global
// -------------------------------------------------------------------------
// SECTION 5: exports
return { f_export: f, goop: g };
}