155505Sshin/* ===-- popcountti2.c - Implement __popcountti2 ----------------------------=== 255505Sshin * 355505Sshin * The LLVM Compiler Infrastructure 455505Sshin * 555505Sshin * This file is dual licensed under the MIT and the University of Illinois Open 655505Sshin * Source Licenses. See LICENSE.TXT for details. 755505Sshin * 855505Sshin * ===----------------------------------------------------------------------=== 955505Sshin * 1055505Sshin * This file implements __popcountti2 for the compiler_rt library. 1155505Sshin * 1255505Sshin * ===----------------------------------------------------------------------=== 1355505Sshin */ 1455505Sshin 1555505Sshin#include "int_lib.h" 1655505Sshin 1755505Sshin#ifdef CRT_HAS_128BIT 1855505Sshin 1955505Sshin/* Returns: count of 1 bits */ 2055505Sshin 2155505SshinCOMPILER_RT_ABI si_int 2255505Sshin__popcountti2(ti_int a) 2355505Sshin{ 2455505Sshin tu_int x3 = (tu_int)a; 2555505Sshin x3 = x3 - ((x3 >> 1) & (((tu_int)0x5555555555555555uLL << 64) | 2655505Sshin 0x5555555555555555uLL)); 27122107Sume /* Every 2 bits holds the sum of every pair of bits (64) */ 2855505Sshin x3 = ((x3 >> 2) & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL)) 2955505Sshin + (x3 & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL)); 3055505Sshin /* Every 4 bits holds the sum of every 4-set of bits (3 significant bits) (32) */ 31119071Sobrien x3 = (x3 + (x3 >> 4)) 3262583Sitojun & (((tu_int)0x0F0F0F0F0F0F0F0FuLL << 64) | 0x0F0F0F0F0F0F0F0FuLL); 3369640Sobrien /* Every 8 bits holds the sum of every 8-set of bits (4 significant bits) (16) */ 3459266Ssteve du_int x2 = (du_int)(x3 + (x3 >> 64)); 3559266Ssteve /* Every 8 bits holds the sum of every 8-set of bits (5 significant bits) (8) */ 3659266Ssteve su_int x = (su_int)(x2 + (x2 >> 32)); 3759266Ssteve /* Every 8 bits holds the sum of every 8-set of bits (6 significant bits) (4) */ 3855505Sshin x = x + (x >> 16); 3962583Sitojun /* Every 8 bits holds the sum of every 8-set of bits (7 significant bits) (2) */ 4062583Sitojun /* Upper 16 bits are garbage */ 4155505Sshin return (x + (x >> 8)) & 0xFF; /* (8 significant bits) */ 4255505Sshin} 4362583Sitojun 4455505Sshin#endif /* CRT_HAS_128BIT */ 4558906Sshin