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| 1 | //===-- Trivial byte per byte implementations ----------------------------===// |
|---|---|
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | // Straightforward implementations targeting the smallest code size possible. |
| 9 | // This needs to be compiled with '-Os' or '-Oz'. |
| 10 | //===----------------------------------------------------------------------===// |
| 11 | |
| 12 | #ifndef LLVM_LIBC_SRC_STRING_MEMORY_UTILS_GENERIC_BYTE_PER_BYTE_H |
| 13 | #define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_GENERIC_BYTE_PER_BYTE_H |
| 14 | |
| 15 | #include "src/__support/macros/attributes.h" // LIBC_INLINE |
| 16 | #include "src/__support/macros/optimization.h" // LIBC_LOOP_NOUNROLL |
| 17 | #include "src/string/memory_utils/utils.h" // Ptr, CPtr |
| 18 | |
| 19 | #include <stddef.h> // size_t |
| 20 | |
| 21 | namespace LIBC_NAMESPACE_DECL { |
| 22 | |
| 23 | [[maybe_unused]] LIBC_INLINE void |
| 24 | inline_memcpy_byte_per_byte(Ptr dst, CPtr src, size_t count, |
| 25 | size_t offset = 0) { |
| 26 | LIBC_LOOP_NOUNROLL |
| 27 | for (; offset < count; ++offset) |
| 28 | dst[offset] = src[offset]; |
| 29 | } |
| 30 | |
| 31 | [[maybe_unused]] LIBC_INLINE void |
| 32 | inline_memmove_byte_per_byte(Ptr dst, CPtr src, size_t count) { |
| 33 | if (count == 0 || dst == src) |
| 34 | return; |
| 35 | if (dst < src) { |
| 36 | LIBC_LOOP_NOUNROLL |
| 37 | for (size_t offset = 0; offset < count; ++offset) |
| 38 | dst[offset] = src[offset]; |
| 39 | } else { |
| 40 | LIBC_LOOP_NOUNROLL |
| 41 | for (ptrdiff_t offset = static_cast<ptrdiff_t>(count - 1); offset >= 0; |
| 42 | --offset) |
| 43 | dst[offset] = src[offset]; |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | [[maybe_unused]] LIBC_INLINE static void |
| 48 | inline_memset_byte_per_byte(Ptr dst, uint8_t value, size_t count, |
| 49 | size_t offset = 0) { |
| 50 | LIBC_LOOP_NOUNROLL |
| 51 | for (; offset < count; ++offset) |
| 52 | dst[offset] = static_cast<cpp::byte>(value); |
| 53 | } |
| 54 | |
| 55 | [[maybe_unused]] LIBC_INLINE BcmpReturnType |
| 56 | inline_bcmp_byte_per_byte(CPtr p1, CPtr p2, size_t count, size_t offset = 0) { |
| 57 | LIBC_LOOP_NOUNROLL |
| 58 | for (; offset < count; ++offset) |
| 59 | if (p1[offset] != p2[offset]) |
| 60 | return BcmpReturnType::nonzero(); |
| 61 | return BcmpReturnType::zero(); |
| 62 | } |
| 63 | |
| 64 | [[maybe_unused]] LIBC_INLINE MemcmpReturnType |
| 65 | inline_memcmp_byte_per_byte(CPtr p1, CPtr p2, size_t count, size_t offset = 0) { |
| 66 | LIBC_LOOP_NOUNROLL |
| 67 | for (; offset < count; ++offset) { |
| 68 | const int32_t a = static_cast<int32_t>(p1[offset]); |
| 69 | const int32_t b = static_cast<int32_t>(p2[offset]); |
| 70 | const int32_t diff = a - b; |
| 71 | if (diff) |
| 72 | return diff; |
| 73 | } |
| 74 | return MemcmpReturnType::zero(); |
| 75 | } |
| 76 | |
| 77 | } // namespace LIBC_NAMESPACE_DECL |
| 78 | |
| 79 | #endif // LLVM_LIBC_SRC_STRING_MEMORY_UTILS_GENERIC_BYTE_PER_BYTE_H |
| 80 |
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