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//===-- 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_STRING_MEMORY_UTILS_MEMCMP_IMPLEMENTATIONS_H
#define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_MEMCMP_IMPLEMENTATIONS_H
#include "src/__support/common.h"
#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY LIBC_LOOP_NOUNROLL
#include "src/__support/macros/properties/architectures.h"
#include "src/string/memory_utils/generic/byte_per_byte.h"
#include "src/string/memory_utils/op_generic.h"
#include "src/string/memory_utils/op_riscv.h"
#include "src/string/memory_utils/utils.h" // CPtr MemcmpReturnType
#include <stddef.h> // size_t
#if defined(LIBC_TARGET_ARCH_IS_X86)
#include "src/string/memory_utils/x86_64/memcmp_implementations.h"
#elif defined(LIBC_TARGET_ARCH_IS_AARCH64)
#include "src/string/memory_utils/aarch64/memcmp_implementations.h"
#endif
namespace __llvm_libc {
[[maybe_unused]] LIBC_INLINE MemcmpReturnType
inline_memcmp_aligned_access_64bit(CPtr p1, CPtr p2, size_t count) {
constexpr size_t kAlign = sizeof(uint64_t);
if (count <= 2 * kAlign)
return inline_memcmp_byte_per_byte(p1, p2, count);
size_t bytes_to_p1_align = distance_to_align_up<kAlign>(p1);
if (auto value = inline_memcmp_byte_per_byte(p1, p2, bytes_to_p1_align))
return value;
size_t offset = bytes_to_p1_align;
size_t p2_alignment = distance_to_align_down<kAlign>(p2 + offset);
for (; offset < count - kAlign; offset += kAlign) {
uint64_t b;
if (p2_alignment == 0)
b = load64_aligned<uint64_t>(p2, offset);
else if (p2_alignment == 4)
b = load64_aligned<uint32_t, uint32_t>(p2, offset);
else if (p2_alignment == 2)
b = load64_aligned<uint16_t, uint16_t, uint16_t, uint16_t>(p2, offset);
else
b = load64_aligned<uint8_t, uint16_t, uint16_t, uint16_t, uint8_t>(
p2, offset);
uint64_t a = load64_aligned<uint64_t>(p1, offset);
if (a != b)
return cmp_neq_uint64_t(Endian::to_big_endian(a),
Endian::to_big_endian(b));
}
return inline_memcmp_byte_per_byte(p1, p2, count, offset);
}
[[maybe_unused]] LIBC_INLINE MemcmpReturnType
inline_memcmp_aligned_access_32bit(CPtr p1, CPtr p2, size_t count) {
constexpr size_t kAlign = sizeof(uint32_t);
if (count <= 2 * kAlign)
return inline_memcmp_byte_per_byte(p1, p2, count);
size_t bytes_to_p1_align = distance_to_align_up<kAlign>(p1);
if (auto value = inline_memcmp_byte_per_byte(p1, p2, bytes_to_p1_align))
return value;
size_t offset = bytes_to_p1_align;
size_t p2_alignment = distance_to_align_down<kAlign>(p2 + offset);
for (; offset < count - kAlign; offset += kAlign) {
uint32_t b;
if (p2_alignment == 0)
b = load32_aligned<uint32_t>(p2, offset);
else if (p2_alignment == 2)
b = load32_aligned<uint16_t, uint16_t>(p2, offset);
else
b = load32_aligned<uint8_t, uint16_t, uint8_t>(p2, offset);
uint32_t a = load32_aligned<uint32_t>(p1, offset);
if (a != b)
return cmp_uint32_t(Endian::to_big_endian(a), Endian::to_big_endian(b));
}
return inline_memcmp_byte_per_byte(p1, p2, count, offset);
}
LIBC_INLINE MemcmpReturnType inline_memcmp(CPtr p1, CPtr p2, size_t count) {
#if defined(LIBC_TARGET_ARCH_IS_X86)
return inline_memcmp_x86(p1, p2, count);
#elif defined(LIBC_TARGET_ARCH_IS_AARCH64)
return inline_memcmp_aarch64(p1, p2, count);
#elif defined(LIBC_TARGET_ARCH_IS_RISCV64)
return inline_memcmp_aligned_access_64bit(p1, p2, count);
#elif defined(LIBC_TARGET_ARCH_IS_RISCV32)
return inline_memcmp_aligned_access_32bit(p1, p2, count);
#else
return inline_memcmp_byte_per_byte(p1, p2, count);
#endif
}
LIBC_INLINE int inline_memcmp(const void *p1, const void *p2, size_t count) {
return static_cast<int>(inline_memcmp(reinterpret_cast<CPtr>(p1),
reinterpret_cast<CPtr>(p2), count));
}
} // namespace __llvm_libc
#endif // LLVM_LIBC_SRC_STRING_MEMORY_UTILS_MEMCMP_IMPLEMENTATIONS_H
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