| // Copyright (c) 2012 Ecma International. All rights reserved. |
| // This code is governed by the BSD license found in the LICENSE file. |
| |
| /*--- |
| es5id: 8.5.1 |
| description: Valid Number ranges |
| ---*/ |
| |
| // Check range support for Number values (IEEE 754 64-bit floats having the form s*m*2**e) |
| // |
| // For normalized floats, sign (s) is +1 or -1, m (mantisa) is a positive integer less |
| // than 2**53 but not less than 2**52 and e (exponent) is an integer ranging from -1074 to 971 |
| // |
| // For denormalized floats, s is +1 or -1, m is a positive integer less than 2**52, and |
| // e is -1074 |
| // |
| // Below 64-bit float values shown for informational purposes. Values may be positive or negative. |
| // Infinity >= ~1.797693134862315907729305190789e+308 >= 2**1024 |
| // MAX_NORM = ~1.797693134862315708145274237317e+308 = (2**53 - 1) * (2**-52) * (2**1023) = (2**53-1) * (2**971) = (2**1024) - (2**971) |
| // MIN_NORM = ~2.2250738585072013830902327173324e-308 = 2**-1022 |
| // MAX_DENORM = ~2.2250738585072008890245868760859e-308 = MIN_NORM - MIN_DENORM = (2**-1022) - (2**-1074) |
| // MIN_DENORM = ~4.9406564584124654417656879286822e-324 = 2**-1074 |
| |
| // Fill an array with 2 to the power of (0 ... -1075) |
| var value = 1; |
| var floatValues = new Array(1076); |
| for(var power = 0; power <= 1075; power++){ |
| floatValues[power] = value; |
| // Use basic math operations for testing, which are required to support 'gradual underflow' rather |
| // than Math.pow etc..., which are defined as 'implementation dependent'. |
| value = value * 0.5; |
| } |
| |
| // The last value is below min denorm and should round to 0, everything else should contain a value |
| if(floatValues[1075] !== 0) { |
| $ERROR("Value after min denorm should round to 0"); |
| } |
| |
| // Validate the last actual value is min denorm |
| if(floatValues[1074] !== 4.9406564584124654417656879286822e-324) { |
| $ERROR("Min denorm value is incorrect: " + floatValues[1074]); |
| } |
| |
| // Validate that every value is half the value before it up to 1 |
| for(var index = 1074; index > 0; index--){ |
| if(floatValues[index] === 0){ |
| $ERROR("2**-" + index + " should not be 0"); |
| } |
| if(floatValues[index - 1] !== (floatValues[index] * 2)){ |
| $ERROR("Value should be double adjacent value at index " + index); |
| } |
| } |
| |
| // Max norm should be supported and compare less than inifity |
| if(!(1.797693134862315708145274237317e+308 < Infinity)){ |
| $ERROR("Max Number value 1.797693134862315708145274237317e+308 should not overflow to infinity"); |
| } |
| |
| // Numbers closer to 2**1024 then max norm should overflow to infinity |
| if(!(1.797693134862315808e+308 === +Infinity)){ |
| $ERROR("1.797693134862315808e+308 did not resolve to Infinity"); |
| } |