| //===-- Implementation of memcmp ------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "src/string/memcmp.h" |
| #include "src/__support/common.h" |
| #include "src/string/memory_utils/elements.h" |
| #include <stddef.h> // size_t |
| |
| namespace __llvm_libc { |
| |
| static int memcmp_aarch64(const char *lhs, const char *rhs, size_t count) { |
| // Use aarch64 strategies (_1, _2, _3 ...) |
| using namespace __llvm_libc::aarch64; |
| |
| if (count == 0) // [0, 0] |
| return 0; |
| if (count == 1) // [1, 1] |
| return ThreeWayCompare<_1>(lhs, rhs); |
| if (count == 2) // [2, 2] |
| return ThreeWayCompare<_2>(lhs, rhs); |
| if (count == 3) // [3, 3] |
| return ThreeWayCompare<_3>(lhs, rhs); |
| if (count < 8) // [4, 7] |
| return ThreeWayCompare<HeadTail<_4>>(lhs, rhs, count); |
| if (count < 16) // [8, 15] |
| return ThreeWayCompare<HeadTail<_8>>(lhs, rhs, count); |
| if (unlikely(count >= 128)) // [128, ∞] |
| return ThreeWayCompare<Align<_16>::Then<Loop<_32>>>(lhs, rhs, count); |
| if (!Equals<_16>(lhs, rhs)) // [16, 16] |
| return ThreeWayCompare<_16>(lhs, rhs); |
| if (count < 32) // [17, 31] |
| return ThreeWayCompare<Tail<_16>>(lhs, rhs, count); |
| if (!Equals<Skip<16>::Then<_16>>(lhs, rhs)) // [32, 32] |
| return ThreeWayCompare<Skip<16>::Then<_16>>(lhs, rhs); |
| if (count < 64) // [33, 63] |
| return ThreeWayCompare<Tail<_32>>(lhs, rhs, count); |
| // [64, 127] |
| return ThreeWayCompare<Skip<32>::Then<Loop<_16>>>(lhs, rhs, count); |
| } |
| |
| LLVM_LIBC_FUNCTION(int, memcmp, |
| (const void *lhs, const void *rhs, size_t count)) { |
| return memcmp_aarch64(reinterpret_cast<const char *>(lhs), |
| reinterpret_cast<const char *>(rhs), count); |
| } |
| |
| } // namespace __llvm_libc |