vbFLOAT Floating Point Type


Topics:

OverviewOverview
Conditional Directives
Type Definitions
Functions


Overview

The vbFLOAT64 class is used to represent 64-bit signed double precision floating point values independently of the operating system or hardware platform used. A double precision floating point number stores binary info within a total of 64 bits. The first bit contains the sign of the mantissa (0 for positive and 1 for negative.) The next 11bits store the exponent, and the remaining 52 bits provide the mantissa, giving an approximate decimal precision of 15 digits.

The vbFLOAT64 class works by separating a 64-bit value into eight separate byte values and reordering the bytes highest-order to lowest-order. A FLOAT64 type has a positive limit of 1.7E+308 and a negative limit of 1.7E-308 with 15-digit precision.


Conditional Directives

__X86__ - This conditional directive is required to maintain the correct byte ordering on PC based Intel x86 systems, which includes Windows 95/98/NT/2000 and UNIX variants such as Linux, SCO, QNX, and x86 Solaris.

__USE_NATIVE_FLOAT_TYPES__ - This conditional directive allows the use of native floating point types in place of platform independent floating point types for debugging purposes only.


Functions

The vbFLOAT64 class is designed to function in the same manner as built-in integer types and includes a full complement of arithmetic and comparison operator overloads. Each operator is overloaded for the following data types: vbFLOAT64, __DPFLOAT__, __LWORD__, __ULWORD__, __WORD__, __SWORD__, __ULWORD__, __USWORD__, __SBYTE__, and __UBYTE__.


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