1*7c3d14c8STreehugger Robot /* ===-- popcountti2.c - Implement __popcountti2 ----------------------------=== 2*7c3d14c8STreehugger Robot * 3*7c3d14c8STreehugger Robot * The LLVM Compiler Infrastructure 4*7c3d14c8STreehugger Robot * 5*7c3d14c8STreehugger Robot * This file is dual licensed under the MIT and the University of Illinois Open 6*7c3d14c8STreehugger Robot * Source Licenses. See LICENSE.TXT for details. 7*7c3d14c8STreehugger Robot * 8*7c3d14c8STreehugger Robot * ===----------------------------------------------------------------------=== 9*7c3d14c8STreehugger Robot * 10*7c3d14c8STreehugger Robot * This file implements __popcountti2 for the compiler_rt library. 11*7c3d14c8STreehugger Robot * 12*7c3d14c8STreehugger Robot * ===----------------------------------------------------------------------=== 13*7c3d14c8STreehugger Robot */ 14*7c3d14c8STreehugger Robot 15*7c3d14c8STreehugger Robot #include "int_lib.h" 16*7c3d14c8STreehugger Robot 17*7c3d14c8STreehugger Robot #ifdef CRT_HAS_128BIT 18*7c3d14c8STreehugger Robot 19*7c3d14c8STreehugger Robot /* Returns: count of 1 bits */ 20*7c3d14c8STreehugger Robot 21*7c3d14c8STreehugger Robot COMPILER_RT_ABI si_int __popcountti2(ti_int a)22*7c3d14c8STreehugger Robot__popcountti2(ti_int a) 23*7c3d14c8STreehugger Robot { 24*7c3d14c8STreehugger Robot tu_int x3 = (tu_int)a; 25*7c3d14c8STreehugger Robot x3 = x3 - ((x3 >> 1) & (((tu_int)0x5555555555555555uLL << 64) | 26*7c3d14c8STreehugger Robot 0x5555555555555555uLL)); 27*7c3d14c8STreehugger Robot /* Every 2 bits holds the sum of every pair of bits (64) */ 28*7c3d14c8STreehugger Robot x3 = ((x3 >> 2) & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL)) 29*7c3d14c8STreehugger Robot + (x3 & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL)); 30*7c3d14c8STreehugger Robot /* Every 4 bits holds the sum of every 4-set of bits (3 significant bits) (32) */ 31*7c3d14c8STreehugger Robot x3 = (x3 + (x3 >> 4)) 32*7c3d14c8STreehugger Robot & (((tu_int)0x0F0F0F0F0F0F0F0FuLL << 64) | 0x0F0F0F0F0F0F0F0FuLL); 33*7c3d14c8STreehugger Robot /* Every 8 bits holds the sum of every 8-set of bits (4 significant bits) (16) */ 34*7c3d14c8STreehugger Robot du_int x2 = (du_int)(x3 + (x3 >> 64)); 35*7c3d14c8STreehugger Robot /* Every 8 bits holds the sum of every 8-set of bits (5 significant bits) (8) */ 36*7c3d14c8STreehugger Robot su_int x = (su_int)(x2 + (x2 >> 32)); 37*7c3d14c8STreehugger Robot /* Every 8 bits holds the sum of every 8-set of bits (6 significant bits) (4) */ 38*7c3d14c8STreehugger Robot x = x + (x >> 16); 39*7c3d14c8STreehugger Robot /* Every 8 bits holds the sum of every 8-set of bits (7 significant bits) (2) */ 40*7c3d14c8STreehugger Robot /* Upper 16 bits are garbage */ 41*7c3d14c8STreehugger Robot return (x + (x >> 8)) & 0xFF; /* (8 significant bits) */ 42*7c3d14c8STreehugger Robot } 43*7c3d14c8STreehugger Robot 44*7c3d14c8STreehugger Robot #endif /* CRT_HAS_128BIT */ 45