26 lines
743 B
JavaScript
26 lines
743 B
JavaScript
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// 20.2.2.16 Math.fround(x)
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var $export = require('./_export')
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, sign = require('./_math-sign')
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, pow = Math.pow
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, EPSILON = pow(2, -52)
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, EPSILON32 = pow(2, -23)
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, MAX32 = pow(2, 127) * (2 - EPSILON32)
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, MIN32 = pow(2, -126);
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var roundTiesToEven = function(n){
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return n + 1 / EPSILON - 1 / EPSILON;
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};
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$export($export.S, 'Math', {
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fround: function fround(x){
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var $abs = Math.abs(x)
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, $sign = sign(x)
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, a, result;
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if($abs < MIN32)return $sign * roundTiesToEven($abs / MIN32 / EPSILON32) * MIN32 * EPSILON32;
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a = (1 + EPSILON32 / EPSILON) * $abs;
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result = a - (a - $abs);
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if(result > MAX32 || result != result)return $sign * Infinity;
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return $sign * result;
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}
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});
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