/* * This file is part of the coreboot project. * * Copyright 2015 Google Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <types.h> /* * Provide platform-independent backend implementation for __builtin_clz() in * <lib.h> in case GCC does not have an assembly version for this arch. */ #if !IS_ENABLED(CONFIG_ARCH_X86) /* work around lack of --gc-sections on x86 */ int __clzsi2(u32 a); int __clzsi2(u32 a) { static const u8 four_bit_table[] = { [0x0] = 4, [0x1] = 3, [0x2] = 2, [0x3] = 2, [0x4] = 1, [0x5] = 1, [0x6] = 1, [0x7] = 1, [0x8] = 0, [0x9] = 0, [0xa] = 0, [0xb] = 0, [0xc] = 0, [0xd] = 0, [0xe] = 0, [0xf] = 0, }; int r = 0; if (!(a & (0xffff << 16))) { r += 16; a <<= 16; } if (!(a & (0xff << 24))) { r += 8; a <<= 8; } if (!(a & (0xf << 28))) { r += 4; a <<= 4; } return r + four_bit_table[a >> 28]; } #endif