diff options
Diffstat (limited to 'payloads/libpayload/libc/libgcc.c')
-rw-r--r-- | payloads/libpayload/libc/libgcc.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/payloads/libpayload/libc/libgcc.c b/payloads/libpayload/libc/libgcc.c new file mode 100644 index 0000000000..86698d8db3 --- /dev/null +++ b/payloads/libpayload/libc/libgcc.c @@ -0,0 +1,68 @@ +/* + * This file is part of the libpayload project. + * + * Copyright 2015 Google Inc. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * Alternatively, this software may be distributed under the terms of the + * GNU General Public License ("GPL") version 2 as published by the Free + * Software Foundation. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <libpayload.h> + +/* + * Provide platform-independent backend implementation for __builtin_clz() in + * <libpayload.h> in case GCC does not have an assembly version for this arch. + */ + +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]; +} |