Brian Swetland

@swetland.frotz.net

1157 Followers 289 Following

Writes the codes. Recovering OS Engineer (BeOS, HiptopOS, Android, LK, Fuchsia). Embedded systems hacker. Hobbyist Digital Designer. Player of video games, tabletop games, D&D, etc. fediverse: @swetland@chaos.social

Sam: Zac. Moose. Zac moos, unconvincingly. Sam: Zac, I'm... Zac moose again, now holding his hands up, fingers splayed. Brennan: Did you factor in the antlers? Sam: I'm factoring them in as we speak. Brennan: Fun fact about moose, they're the last surviving species of North American megafauna. Sam: No points for Brennan. Brennan: Points for the audience for learning. Josh: Brennan, it's not the extra credit show, it's make animal sounds! Come on, dude, I got places to be. Zac: Josh has to leave in four minutes. Brennan ducks behind his podium trying not to do a spit-take. Sam: Zac, I think that point goes to you, well done.
Shot of a flat panel TV showing a drama scene: boy, girl, and big fluffy poodle in a park, cherry trees blooming. The boy grips an IV stand tightly, says "I'm not able to love you!" through gritted teeth while the girl cries.
The best method for counting bits in a 32-bit integer v is the following: v = v - ((v >> 1) & 0x55555555); // reuse input as temporary v = (v & 0x33333333) + ((v >> 2) & 0x33333333); // temp c = ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24; // count The best bit counting method takes only 12 operations, which is the same as the lookup-table method, but avoids the memory and potential cache misses of a table. It is a hybrid between the purely parallel method above and the earlier methods using multiplies (in the section on counting bits with 64-bit instructions), though it doesn't use 64-bit instructions. The counts of bits set in the bytes is done in parallel, and the sum total of the bits set in the bytes is computed by multiplying by 0x1010101 and shifting right 24 bits.