1214152Sed/* ===-- popcountti2.c - Implement __popcountti2 ----------------------------=== 2214152Sed * 3214152Sed * The LLVM Compiler Infrastructure 4214152Sed * 5222656Sed * This file is dual licensed under the MIT and the University of Illinois Open 6222656Sed * Source Licenses. See LICENSE.TXT for details. 7214152Sed * 8214152Sed * ===----------------------------------------------------------------------=== 9214152Sed * 10214152Sed * This file implements __popcountti2 for the compiler_rt library. 11214152Sed * 12214152Sed * ===----------------------------------------------------------------------=== 13214152Sed */ 14214152Sed 15239138Sandrew#include "int_lib.h" 16239138Sandrew 17263763Sdim#ifdef CRT_HAS_128BIT 18214152Sed 19214152Sed/* Returns: count of 1 bits */ 20214152Sed 21214152Sedsi_int 22214152Sed__popcountti2(ti_int a) 23214152Sed{ 24214152Sed tu_int x3 = (tu_int)a; 25214152Sed x3 = x3 - ((x3 >> 1) & (((tu_int)0x5555555555555555uLL << 64) | 26214152Sed 0x5555555555555555uLL)); 27214152Sed /* Every 2 bits holds the sum of every pair of bits (64) */ 28214152Sed x3 = ((x3 >> 2) & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL)) 29214152Sed + (x3 & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL)); 30214152Sed /* Every 4 bits holds the sum of every 4-set of bits (3 significant bits) (32) */ 31214152Sed x3 = (x3 + (x3 >> 4)) 32214152Sed & (((tu_int)0x0F0F0F0F0F0F0F0FuLL << 64) | 0x0F0F0F0F0F0F0F0FuLL); 33214152Sed /* Every 8 bits holds the sum of every 8-set of bits (4 significant bits) (16) */ 34214152Sed du_int x2 = (du_int)(x3 + (x3 >> 64)); 35214152Sed /* Every 8 bits holds the sum of every 8-set of bits (5 significant bits) (8) */ 36214152Sed su_int x = (su_int)(x2 + (x2 >> 32)); 37214152Sed /* Every 8 bits holds the sum of every 8-set of bits (6 significant bits) (4) */ 38214152Sed x = x + (x >> 16); 39214152Sed /* Every 8 bits holds the sum of every 8-set of bits (7 significant bits) (2) */ 40214152Sed /* Upper 16 bits are garbage */ 41214152Sed return (x + (x >> 8)) & 0xFF; /* (8 significant bits) */ 42214152Sed} 43214152Sed 44263763Sdim#endif /* CRT_HAS_128BIT */ 45