Function pack

test/form/samples/supports-core-js/_expected.js:6137–6193

(number, mantissaLength, bytes)

	var LN2 = Math.LN2;

	var pack = function (number, mantissaLength, bytes) {
	  var buffer = $Array(bytes);
	  var exponentLength = bytes * 8 - mantissaLength - 1;
	  var eMax = (1 << exponentLength) - 1;
	  var eBias = eMax >> 1;
	  var rt = mantissaLength === 23 ? pow(2, -24) - pow(2, -77) : 0;
	  var sign = number < 0 || number === 0 && 1 / number < 0 ? 1 : 0;
	  var index = 0;
	  var exponent, mantissa, c;
	  number = abs(number);
	  // eslint-disable-next-line no-self-compare -- NaN check
	  if (number !== number || number === Infinity) {
	    // eslint-disable-next-line no-self-compare -- NaN check
	    mantissa = number !== number ? 1 : 0;
	    exponent = eMax;
	  } else {
	    exponent = floor(log(number) / LN2);
	    c = pow(2, -exponent);
	    if (number * c < 1) {
	      exponent--;
	      c *= 2;
	    }
	    if (exponent + eBias >= 1) {
	      number += rt / c;
	    } else {
	      number += rt * pow(2, 1 - eBias);
	    }
	    if (number * c >= 2) {
	      exponent++;
	      c /= 2;
	    }
	    if (exponent + eBias >= eMax) {
	      mantissa = 0;
	      exponent = eMax;
	    } else if (exponent + eBias >= 1) {
	      mantissa = (number * c - 1) * pow(2, mantissaLength);
	      exponent += eBias;
	    } else {
	      mantissa = number * pow(2, eBias - 1) * pow(2, mantissaLength);
	      exponent = 0;
	    }
	  }
	  while (mantissaLength >= 8) {
	    buffer[index++] = mantissa & 255;
	    mantissa /= 256;
	    mantissaLength -= 8;
	  }
	  exponent = exponent << mantissaLength | mantissa;
	  exponentLength += mantissaLength;
	  while (exponentLength > 0) {
	    buffer[index++] = exponent & 255;
	    exponent /= 256;
	    exponentLength -= 8;
	  }
	  buffer[index - 1] |= sign * 128;
	  return buffer;
	};