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December 28, 2016 21:11
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asm.js sample
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function fast_fib_module(stdlib, foreign, heap) { | |
"use asm"; | |
function fib(n) { | |
n = n|0; | |
// nはint(符号の有無が不明の状態) | |
// 3はfixnum(0~2^31) | |
// 比較するためにnをシフト演算でunsignedに変換する | |
if (n >>> 0 < 3) { | |
return 1|0; | |
} | |
// fibの引数の型はintなのでintのサブセットであるsigned intで渡す | |
return (fib((n-1)|0) + fib((n-2)|0))|0; | |
} | |
return { | |
fib:fib | |
}; | |
} | |
fast_fib = fast_fib_module(window).fib; | |
function slow_fib(n) { | |
if (n < 3) { | |
return 1; | |
} | |
return slow_fib(n-1) + slow_fib(n-2); | |
} | |
function fast_check(n) { | |
console.time("ASM:fib(" + n + ")"); | |
console.log(fast_fib(n)); | |
console.timeEnd("ASM:fib(" + n + ")"); | |
} | |
function slow_check(n) { | |
console.time("NORMAL:fib(" + n + ")"); | |
console.log(slow_fib(n)); | |
console.timeEnd("NORMAL:fib(" + n + ")"); | |
} |
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[01:40:15.035] fast_check(35) | |
[01:40:15.037] undefined | |
[01:40:15.037] ASM:fib(35): タイマー開始 | |
[01:40:15.076] 9227465 | |
[01:40:15.076] ASM:fib(35): 39ms | |
-- | |
[01:40:21.539] slow_check(35) | |
[01:40:21.541] undefined | |
[01:40:21.541] NORMAL:fib(35): タイマー開始 | |
[01:40:26.163] 9227465 | |
[01:40:26.163] NORMAL:fib(35): 4622ms |
When I try this i Firefox (27.0), I get this re. line 15: "TypeError: asm.js type error: non-expression-statement call must be coerced"
Does that explain why slow_check is faster than fast_check?
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How do I use this in my browser? Do I need more than your fibonacci.js to see the effect of ASM? Do I have to use a special version of Firefox?