pfloat.py 文件源码

def setf(self, value):
        """store /value/ into a binary format"""
        exponentbias = (2**self.components[1])/2 - 1
        m,e = math.frexp(value)

        # extract components from value
        s = math.copysign(1.0, m)
        m = abs(m)

        # convert to integrals
        sf = 1 if s < 0 else 0
        exponent = e + exponentbias - 1
        m = m*2.0 - 1.0     # remove the implicit bit
        mantissa = int(m * (2**self.components[2]))

        # store components
        result = bitmap.zero
        result = bitmap.push( result, bitmap.new(sf,self.components[0]) )
        result = bitmap.push( result, bitmap.new(exponent,self.components[1]) )
        result = bitmap.push( result, bitmap.new(mantissa,self.components[2]) )

        return self.__setvalue__( result[0] )