fp-truncate

Tools and programs for truncating the number of bits in the significand of floating-point numbers. The numbers can be represented in decimal, binary or hexadecimal.

Command-line programs

The command-line programs take the same set of arguments, one program is provided for each input representation (e.g., 32-bit binary, 64-bit hexadecimal). The first argument is the floating-point value to be truncated, expressed in the appropriate representation. The programs are:

• tr32b - accepts 32-bit binary string inputs
• tr64b - accepts 64-bit binary string inputs
• tr32h - accepts 32-bit decimal string inputs
• tr64h - accepts 64-bit decimal inputs
• tr32d - accepts 32-bit hexadecimal inputs
• tr64d - accepts 64-bit hexadecimal inputs

The number of bits in the significand of the output is indicated with either 1 or 2 arguments. If one argument is provided it is interpreted as the number of significand bits in the output, and the output will be a single line:

tr32d 3.14159 5
3.125

If two arguments are provided they are interpreted as a range of significand sizes, resulting in one line of output for each significand size in the range:

tr32d 3.14159 5 7
3.125
3.15625
3.140625

or in reverse order:

tr32d 3.14159 7 5
3.140625
3.15625
3.125

A single option -b or --base= may be given, which specifies the base of the program output:

tr32d 3.14159 5 -b 2
01000000010010000000000000000000

Valid bases are 2 (binary), 10 (decimal) and 16 (hexadecimal).

The fp-truncate library

The backend used by the command-line programs can be used as a library to write your own programs. The fp-truncate library exports the following modules:

• Truncate - The core truncation library
• Truncate.Main - A main program to implement the command-line programs
• Truncate.Main.Readers - Readers for processing command-line arguments