You guys are pretty clever! I thought at first that this problem was too simple and wouldn't lend itself to crazy tricks. Boy, was I wrong. I think this will really be interesting when we try it with a slightly more open-ended problem.

Here's another 36-byte solution that goes down a little bit different path by getting rid of the loop counter and using instead a 16-bit variable to both accumulate the result and stop the loop. It seemed like a good idea at the time, but I don't yet see a way to get rid of that nasty '256'.

-- Russ

UC TestFlip(UC c) 
{
//c=c/2&85|c*2&170;c=c/4&51|c*4&204;RT c>>4|c<<4;       // (47) Cooper
//UC r,i=8;WH(i--){r>>=1;r|=c&128;c*=2;}RT r;           // (43) Karas
//UC r,i=8;WH(i--){r*=2;r|=c&1;c/=2;}RT r;              // (40) Karas
//UC r,i=8;WH(i--){r=r*2|c&1;c/=2;}RT r;                // (38) Cooper
//UC r,i=8;WH(i--)r=r*2|c&1,c/=2;RT r;                  // (36) Kelly
//UC r,i=1;WH(r+=c&i?r++:r,i+=i);RT r;                  // (36) Waclawek
//UC r,i=1;WH(r+=r+c/i%2,i+=i);RT r;                    // (34) Kelly
  IN r=1;WH(r<256)r=r*2|c&1,c/=2;RT r;                  // (36) Cooper
}