How to reverse a Unsigned Char??

[ranjanmg1]

I have a unsigned char.. i need to reverse it.. what the easiest way to
do it?? i dont want to tap each bit save and restore etc etc....

Is it possible to perform some bitwise operation which will give the
reversed char.

e.g., unsigned char x = 0x8A
am expecting an output after reversal x = 0x51

 

[mark_bluemel]

I have a unsigned char.. i need to reverse it.. what the easiest way to
do it?? i dont want to tap each bit save and restore etc etc....

Is it possible to perform some bitwise operation which will give the
reversed char.

Go to Google Groups and search for "reverse" in comp.lang.c

 

[Jens Thoms Toerring]

I have a unsigned char.. i need to reverse it.. what the easiest way to
do it?? i dont want to tap each bit save and restore etc etc....

Is it possible to perform some bitwise operation which will give the
reversed char.

e.g., unsigned char x = 0x8A
am expecting an output after reversal x = 0x51

There's no operator or standard function for this in C, but if you
google for 'reverse bits in a byte' you will find e.g.

http://graphics.stanford.edu/~seander/bithacks.html#BitReverseObvious

and lots of other results.
Regards, Jens

 

[Jordan Abel]

2006-10-24 <[email protected]>,

I have a unsigned char.. i need to reverse it.. what the easiest way to
do it?? i dont want to tap each bit save and restore etc etc....

Is it possible to perform some bitwise operation which will give the
reversed char.

e.g., unsigned char x = 0x8A
am expecting an output after reversal x = 0x51

static unsigned char CSStab4[256]=

{
0x00,0x80,0x40,0xc0,0x20,0xa0,0x60,0xe0,
0x10,0x90,0x50,0xd0,0x30,0xb0,0x70,0xf0,
....
And so on in much the same manner.

x = 0x8a;
x[CSStab4] == 0x51;

 

[pete]

I have a unsigned char.. i need to reverse it.. what the easiest way to
do it?? i dont want to tap each bit save and restore etc etc....

Is it possible to perform some bitwise operation which will give the
reversed char.

e.g., unsigned char x = 0x8A
am expecting an output after reversal x = 0x51

unsigned char bit_rev(unsigned char byte)
{
unsigned hi_mask = ((unsigned char)-1 >> 1) + 1;
unsigned lo_mask = 1;

do {
if (!(byte & hi_mask) != !(byte & lo_mask)) {
byte ^= hi_mask | lo_mask;
}
hi_mask >>= 1;
lo_mask <<= 1;
} while (hi_mask > lo_mask);
return byte;
}