First step: s |= ((short)(uc & 0xf0)) << 4pcmattman wrote:Can anyone help me out? I need to somehow put the top 4 bits of an unsigned char into bits 8-11 of a short, and the bottom 4 into bits 0-3.
I can get the bits out of the char, but I don't know how to put them into the short.
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struct shortVariable
{
unsigned bits0to3 : 4;
unsigned bits4to7 : 4;
unsigned bits8to11 : 4;
unsigned bits12-15 : 4;
};
struct shortVariable sv;
unsigned char data;
...
sv.bits0to3 = data & 0x0f;
sv.bits8to11 = (data & 0xf0) << 4;
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sv.bits8to11 = (data & 0xf0) >> 4; 
...Code: Select all
//-[ BitField<T> ]--------------------------------------------------------------
template <typename T>
class BitField {
T bits;
public:
BitField(void) : bits(0) {}
BitField(T data) : bits(data) {}
BitField(voidp addr) : bits(*(T *)addr) {}
T get(int16u, int16u);
void set(int16u, int16u, T);
} __attribute__((packed));
//--------------------------------------------------------------[ BitField<T> ]-
//-[ BitField<T>::get ]---------------------------------------------------------
template <class T> T
BitField<T>::get
( int16u base, //- first bit of data field
int16u size //- number of bits to fetch
)
{ const T mask = (((T)1 << size) - (T)1);
return((bits >> base) & mask);
}
//---------------------------------------------------------[ BitField<T>::get ]-
//-[ BitField<T>::set ]---------------------------------------------------------
template <class T> void
BitField<T>::set
( int16u base, //- first bit of data field
int16u size, //- number of bits to store
T data //- value to store in field
)
{ const T mask = (((T)1 << size) - (T)1) << base;
bits = (bits & ~mask) | ((data << base) & mask);
}
//---------------------------------------------------------[ BitField<T>::set ]-
You can use it like:Can anyone help me out? I need to somehow put the top 4 bits of an unsigned char into bits 8-11 of a short, and the bottom 4 into bits 0-3.
I can get the bits out of the char, but I don't know how to put them into the short.
Code: Select all
BitField<char> byte(/*value*/);
BitField<short> word(/*value*/);
word.set(8, 4/*bit 8-11*/, byte.get(0,4/*bit 0-3*/));
