float_set

Concepts

Floating Point Numbers (XFL)

Behaviour

C

• Compute an XFL (xls17) floating point from the provided exponent and mantissa
• Return that XFL as an int64_t

JavaScript

• Sets the exponent and mantissa for a float representation.
• Returns an error code or a new XFL as a bigint.

Definition

C

int64_t float_set (
    int32_t exponent,
    int64_t mantissa
);

JavaScript

function float_set(exponent: number, mantissa: number): ErrorCode | bigint

Example

C

int64_t small_amount =
  float_set(-81, 1);

JavaScript

const small_amount = float_set(-81, 1);

Parameters

C

Name	Type	Description
exponent	int32_t	An exponent in the range -96 to 80
mantissa	int64_t	A mantissa. If negative then the sign of the float is negative.

Caution

When setting a mantissa that is greater or fewer than 16 decimal digits the exponent will be adjusted to ensure the mantissa is exactly 16 digits. This adjustment may result in an INVALID_FLOAT in some circumstances.

Special case

XFL canonical 0 is also 0 in the enclosing number. Thus there is never a need to call float_set(0,0);

JavaScript

Name	Type	Description
exponent	bigint	An exponent in the range -96 to 80
mantissa	bigint	A mantissa. If negative then the sign of the float is negative.

Return Code

C

Type	Description
int64_t	The XFL (xls17) enclosing number If negative, an error: INVALID_FLOAT - The adjustment of the mantissa to 16 digits produced an under or overflow.

JavaScript

Type	Description
ErrorCode | bigint	An error code or the XFL (xls17) enclosing number.