decimal-fxp.py

#!/usr/bin/env python

from decimal import *

base_binary = Decimal(2)**Decimal(64)
base_decimal = Decimal(10)**Decimal(20)

def fix_binary(n):
    return Decimal(n) * base_binary

def unfix_binary(n):
    return Decimal(n) / base_binary

def fix_decimal(n):
    return Decimal(n) * base_decimal

def unfix_decimal(n):
    return Decimal(n) / base_decimal

n = "1.2"

fxp_binary = fix_binary(n)
hex_fxp_binary = hex(int(fxp_binary))
print "Base 2^64 fixed-point:"
print fxp_binary
print (len(hex_fxp_binary) - 3) / 2, hex_fxp_binary
print unfix_binary(int(fxp_binary))

fxp_decimal = fix_decimal(n)
hex_fxp_decimal = hex(int(fxp_decimal))
print "Base 10^20 fixed-point:"
print fxp_decimal
print (len(hex_fxp_decimal) - 3) / 2, hex_fxp_decimal
print unfix_decimal(int(fxp_decimal))