Bit-level unpacking of floating-point data
/*
Java Programming for Engineers
Julio Sanchez
Maria P. Canton
ISBN: 0849308100
Publisher: CRC Press
*/
// Java for Engineers
//Filename: BitOps
//Reference: Chapter 24
//Description:
// Bit-level unpacking of floating-pioint data
//Requires:
// Keyin class in current directory
class BitOps {
public static void main(String[] args) {
// Definition of bit field masks for double
final long SIGN = 0x8000000000000000L;
final long EXPN = 0x7ff0000000000000L;
final long SGNF = 0x000fffffffffffffL;
final long BIT1 = 0x8000000000000000L;
// Storage for bit fields
long s; // Sign
long e; // Exponent field
long m; // Significand (mantissa) field
String eS; // For conversions
double num;
long binVal;
long t;
// Get user input
num = 3.4d;
binVal = Double.doubleToRawLongBits(num);
// Display hex bits
System.out.println("As long = " + Long.toHexString(binVal));
// Display bit fields of double format
s = binVal & SIGN;
if (s != 0)
System.out.println("Sign = -");
else
System.out.println("Sign = +");
// Mask out exponent field
e = (binVal & EXPN);
eS = Long.toHexString(e);
System.out.println("Exponent = " + eS);
// Mask out significand field
m = (binVal & SGNF);
eS = Long.toHexString(m);
System.out.println("Significand = " + eS);
System.out.println("\nFields in binary");
if (s != 0)
System.out.println("Sign bit = 1");
else
System.out.println("Sign bit = 0");
// Display binary exponent
// Eliminate sign bit
e = e << 1;
System.out.print("Exponent = ");
for (int k = 0; k < 11; k++) {
t = e & BIT1;
// System.out.println(Long.toHexString(t));
if (t != 0)
System.out.print("1");
else
System.out.print("0");
e = e << 1;
}
System.out.println("\n |-11 bits-|");
// Display binary significand
// Eliminate exponent and sign bits
m = m << 12;
System.out.print("Significand = 1.");
for (int j = 0; j < 51; j++) {
t = m & BIT1;
if (t != 0)
System.out.print("1");
else
System.out.print("0");
m = m << 1;
}
System.out.println("\n ^ |");
System.out.println("implicit bit -| | ----- 52 bits -->");
}
}
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