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set 4-bit nibble in an int type
(3个答案)
4年前关闭。
我被困在如何将4位值替换为原始32位整数的某个位置。非常感谢所有帮助!
这里:
(3个答案)
4年前关闭。
我被困在如何将4位值替换为原始32位整数的某个位置。非常感谢所有帮助!
/**
* Set a 4-bit nibble in an int.
*
* Ints are made of eight bytes, numbered like so:
* 7777 6666 5555 4444 3333 2222 1111 0000
*
* For a graphical representation of this:
* 1 1 1 1 1 1
* 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |Nibble3|Nibble2|Nibble1|Nibble0|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* Examples:
* setNibble(0xAAA5, 0x1, 0); // => 0xAAA1
* setNibble(0x56B2, 0xF, 3); // => 0xF6B2
*
* @param num The int that will be modified.
* @param nibble The nibble to insert into the integer.
* @param which Selects which nibble to modify - 0 for least-significant nibble.
*
* @return The modified int.
*/
public static int setNibble(int num, int nibble, int which)
{
int shifted = (nibble << (which<<2));
int temp = (num & shifted);
//this is the part I am stuck on, how can I replace the original
// which location with the nibble that I want? Thank you!
return temp;
}
最佳答案
public static int setNibble(int num, int nibble, int which) {
return num & ~(0xF << (which * 4)) | (nibble << (which * 4));
}
这里:
& ~(0xF << (which * 4))
掩盖了半字节的原始值; | (nibble << (which * 4))
将其设置为新值。 10-02 22:08