diff options
Diffstat (limited to 'src/lib/libgcc.c')
| -rw-r--r-- | src/lib/libgcc.c | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/src/lib/libgcc.c b/src/lib/libgcc.c new file mode 100644 index 0000000000..14685becf0 --- /dev/null +++ b/src/lib/libgcc.c @@ -0,0 +1,56 @@ +/* + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc. + */ + +#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 |