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LibJS: Add spec comments to Value::to_u16()

This commit is contained in:
Linus Groh 2022-12-10 00:01:45 +00:00
parent b8ae9ca206
commit 42eac3b7d3

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@ -959,15 +959,24 @@ ThrowCompletionOr<i16> Value::to_i16(VM& vm) const
// 7.1.9 ToUint16 ( argument ), https://tc39.es/ecma262/#sec-touint16
ThrowCompletionOr<u16> Value::to_u16(VM& vm) const
{
double value = TRY(to_number(vm)).as_double();
if (!isfinite(value) || value == 0)
// 1. Let number be ? ToNumber(argument).
double number = TRY(to_number(vm)).as_double();
// 2. If number is not finite or number is either +0𝔽 or -0𝔽, return +0𝔽.
if (!isfinite(number) || number == 0)
return 0;
auto int_val = floor(fabs(value));
if (signbit(value))
// 3. Let int be the mathematical value whose sign is the sign of number and whose magnitude is floor(abs((number))).
auto int_val = floor(fabs(number));
if (signbit(number))
int_val = -int_val;
// 4. Let int16bit be int modulo 2^16.
auto int16bit = fmod(int_val, NumericLimits<u16>::max() + 1.0);
if (int16bit < 0)
int16bit += NumericLimits<u16>::max() + 1.0;
// 5. Return 𝔽(int16bit).
return static_cast<u16>(int16bit);
}