Java Float to floatToHalf(float f)

Description

float To Half

License

Open Source License

Declaration

public static final int floatToHalf(float f) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

public class Main {
    public static final int floatToHalf(float f) {
        int i = Float.floatToRawIntBits(f);
        // unpack the s, e and m of the float
        int s = (i >> 16) & 0x00008000;
        int e = ((i >> 23) & 0x000000ff) - (127 - 15);
        int m = i & 0x007fffff;
        // pack them back up, forming a half
        if (e <= 0) {
            if (e < -10) {
                // E is less than -10. The absolute value of f is less than
                // HALF_MIN
                // convert f to 0
                return 0;
            }//from  w w w.  ja v  a2s  .co m
            // E is between -10 and 0.
            m = (m | 0x00800000) >> (1 - e);
            // Round to nearest, round "0.5" up.
            if ((m & 0x00001000) == 0x00001000)
                m += 0x00002000;
            // Assemble the half from s, e (zero) and m.
            return s | (m >> 13);
        } else if (e == 0xff - (127 - 15)) {
            if (m == 0) {
                // F is an infinity; convert f to a half infinity
                return s | 0x7c00;
            } else {
                // F is a NAN; we produce a half NAN that preserves the sign bit
                // and the 10 leftmost bits of the significand of f
                m >>= 13;
                return s | 0x7c00 | m | ((m == 0) ? 0 : 1);
            }
        } else {
            // E is greater than zero. F is a normalized float. Round to
            // nearest, round "0.5" up
            if ((m & 0x00001000) == 0x00001000) {
                m += 0x00002000;
                if ((m & 0x00800000) == 0x00800000) {
                    m = 0;
                    e += 1;
                }
            }
            // Handle exponent overflow
            if (e > 30) {
                // overflow (); // Cause a hardware floating point overflow;
                return s | 0x7c00; // if this returns, the half becomes an
            } // infinity with the same sign as f.
              // Assemble the half from s, e and m.
            return s | (e << 10) | (m >> 13);
        }
    }
}

Related

1. floatToBasicType(float f, Class clazz)
2. floatToBinaryStringUnsigned(float value)
3. floatToChar(float[] values)
4. FloatToInt(double x)
5. floatToIntColor(float value)
6. floatToPrefixCoded(float val)
7. floatToRegisters(float f)