2 * This file is part of the coreboot project.
4 * Copyright 2015 Google Inc.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; version 2 of the License.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
19 * Provide platform-independent backend implementation for __builtin_clz() in
20 * <lib.h> in case GCC does not have an assembly version for this arch.
23 #if !IS_ENABLED(CONFIG_ARCH_X86) /* work around lack of --gc-sections on x86 */
27 static const u8 four_bit_table
[] = {
28 [0x0] = 4, [0x1] = 3, [0x2] = 2, [0x3] = 2,
29 [0x4] = 1, [0x5] = 1, [0x6] = 1, [0x7] = 1,
30 [0x8] = 0, [0x9] = 0, [0xa] = 0, [0xb] = 0,
31 [0xc] = 0, [0xd] = 0, [0xe] = 0, [0xf] = 0,
35 if (!(a
& (0xffff << 16))) {
40 if (!(a
& (0xff << 24))) {
45 if (!(a
& (0xf << 28))) {
50 return r
+ four_bit_table
[a
>> 28];