On 02/04/2017 6:28 AM, Nicholas Wilson wrote:
I have this c++ code with clang
uint32_t val = 1111490560;
int leading_zeros = __builtin_clz( val << 1); // equals 0
int leading_ones = __builtin_clz(~val << 1); // equals 1
return (lz == 0 ? lo - 1 : -lz);
and want to translate it to D.
import core.bitop : bsf,bsr;
uint val = 1111490560;
int leading_zeros_r = bsr( val << 1); // equals 31
int leading_ones_r = bsr(~val << 1); // equals 30
int leading_zeros_f = bsf( val << 1); // equals 23
int leading_ones_f = bsf(~val << 1); // equals 1
From what I gather from wikipedia I ought to be using bsr. But none of
them work.
WTF?
BSR looks like its working.
http://x86.renejeschke.de/html/file_module_x86_id_20.html
http://stackoverflow.com/a/9353998
