| /* SPDX-License-Identifier: GPL-2.0-only */ | |
| #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. | |
| */ | |
| /* | |
| * FIXME | |
| * work around lack of --gc-sections on x86 | |
| * defined in rv32 libgcc.a | |
| */ | |
| #if !ENV_X86 && !ENV_RISCV | |
| 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 & (0xffffU << 16))) { | |
| r += 16; | |
| a <<= 16; | |
| } | |
| if (!(a & (0xffU << 24))) { | |
| r += 8; | |
| a <<= 8; | |
| } | |
| if (!(a & (0xfU << 28))) { | |
| r += 4; | |
| a <<= 4; | |
| } | |
| return r + four_bit_table[a >> 28]; | |
| } | |
| #endif |