#1,088 – How 32-Bit Floating Point Numbers Are Stored in .NET, part I

Floating point numbers in .NET (on Intel-based PCs) are stored using the IEEE 754 standard, which defines how to store both 32-bit (float) and 64-bit (double) floating points.

Floating point numbers are stored in memory by storing the value as a binary floating point value represented using scientific notation (binary).

For example, to store a decimal value of 7.25:

1088-001

The exponent is expressed as binary, so it has a value of 2.

We can now store this floating point number in memory by storing three things:

  • The sign of the number (positive)
  • The mantissa (1.1101)
  • The exponent (10)

On Intel-based PCs, 32-bit floating point numbers are stored as follows:

  • 1 bit to store the sign (0 for positive numbers, 1 for negative numbers)
  • 8 bits to store the exponent
  • 23 bits to store the mantissa

More coming in part II

Advertisements

About Sean
Software developer in the Twin Cities area, passionate about software development and sailing.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: