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//===-- Implementation of bcmp --------------------------------------------===//
//
// 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_BCMP_IMPLEMENTATIONS_H
#define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_BCMP_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/op_aarch64.h"
#include "src/string/memory_utils/op_builtin.h"
#include "src/string/memory_utils/op_generic.h"
#include "src/string/memory_utils/op_x86.h"
#include <stddef.h> // size_t
namespace __llvm_libc {
[[maybe_unused]] LIBC_INLINE BcmpReturnType
inline_bcmp_byte_per_byte(CPtr p1, CPtr p2, size_t offset, size_t count) {
LIBC_LOOP_NOUNROLL
for (; offset < count; ++offset)
if (p1[offset] != p2[offset])
return BcmpReturnType::NONZERO();
return BcmpReturnType::ZERO();
}
[[maybe_unused]] LIBC_INLINE BcmpReturnType
inline_bcmp_aligned_access_64bit(CPtr p1, CPtr p2, size_t count) {
constexpr size_t kAlign = sizeof(uint64_t);
if (count <= 2 * kAlign)
return inline_bcmp_byte_per_byte(p1, p2, 0, count);
size_t bytes_to_p1_align = distance_to_align_up<kAlign>(p1);
if (auto value = inline_bcmp_byte_per_byte(p1, p2, 0, 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 a;
if (p2_alignment == 0)
a = load64_aligned<uint64_t>(p2, offset);
else if (p2_alignment == 4)
a = load64_aligned<uint32_t, uint32_t>(p2, offset);
else if (p2_alignment == 2)
a = load64_aligned<uint16_t, uint16_t, uint16_t, uint16_t>(p2, offset);
else
a = load64_aligned<uint8_t, uint16_t, uint16_t, uint16_t, uint8_t>(
p2, offset);
uint64_t b = load64_aligned<uint64_t>(p1, offset);
if (a != b)
return BcmpReturnType::NONZERO();
}
return inline_bcmp_byte_per_byte(p1, p2, offset, count);
}
[[maybe_unused]] LIBC_INLINE BcmpReturnType
inline_bcmp_aligned_access_32bit(CPtr p1, CPtr p2, size_t count) {
constexpr size_t kAlign = sizeof(uint32_t);
if (count <= 2 * kAlign)
return inline_bcmp_byte_per_byte(p1, p2, 0, count);
size_t bytes_to_p1_align = distance_to_align_up<kAlign>(p1);
if (auto value = inline_bcmp_byte_per_byte(p1, p2, 0, 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 a;
if (p2_alignment == 0)
a = load32_aligned<uint32_t>(p2, offset);
else if (p2_alignment == 2)
a = load32_aligned<uint16_t, uint16_t>(p2, offset);
else
a = load32_aligned<uint8_t, uint16_t, uint8_t>(p2, offset);
uint32_t b = load32_aligned<uint32_t>(p1, offset);
if (a != b)
return BcmpReturnType::NONZERO();
}
return inline_bcmp_byte_per_byte(p1, p2, offset, count);
}
#if defined(LIBC_TARGET_ARCH_IS_X86) || defined(LIBC_TARGET_ARCH_IS_AARCH64)
[[maybe_unused]] LIBC_INLINE BcmpReturnType
inline_bcmp_generic_gt16(CPtr p1, CPtr p2, size_t count) {
if (count < 256)
return generic::Bcmp<16>::loop_and_tail(p1, p2, count);
if (auto value = generic::Bcmp<64>::block(p1, p2))
return value;
align_to_next_boundary<64, Arg::P1>(p1, p2, count);
return generic::Bcmp<64>::loop_and_tail(p1, p2, count);
}
#endif // defined(LIBC_TARGET_ARCH_IS_X86) ||
// defined(LIBC_TARGET_ARCH_IS_AARCH64)
#if defined(LIBC_TARGET_ARCH_IS_X86)
[[maybe_unused]] LIBC_INLINE BcmpReturnType
inline_bcmp_x86_sse2_gt16(CPtr p1, CPtr p2, size_t count) {
if (count <= 32)
return x86::sse2::Bcmp<16>::head_tail(p1, p2, count);
if (count < 256)
return x86::sse2::Bcmp<16>::loop_and_tail(p1, p2, count);
if (auto value = x86::sse2::Bcmp<16>::block(p1, p2))
return value;
align_to_next_boundary<16, Arg::P1>(p1, p2, count);
return x86::sse2::Bcmp<64>::loop_and_tail(p1, p2, count);
}
[[maybe_unused]] LIBC_INLINE BcmpReturnType
inline_bcmp_x86_avx2_gt16(CPtr p1, CPtr p2, size_t count) {
if (count <= 32)
return x86::sse2::Bcmp<16>::head_tail(p1, p2, count);
if (count <= 64)
return x86::avx2::Bcmp<32>::head_tail(p1, p2, count);
if (count <= 128)
return x86::avx2::Bcmp<64>::head_tail(p1, p2, count);
if (LIBC_UNLIKELY(count >= 256)) {
if (auto value = x86::avx2::Bcmp<64>::block(p1, p2))
return value;
align_to_next_boundary<64, Arg::P1>(p1, p2, count);
}
return x86::avx2::Bcmp<64>::loop_and_tail(p1, p2, count);
}
[[maybe_unused]] LIBC_INLINE BcmpReturnType
inline_bcmp_x86_avx512bw_gt16(CPtr p1, CPtr p2, size_t count) {
if (count <= 32)
return x86::sse2::Bcmp<16>::head_tail(p1, p2, count);
if (count <= 64)
return x86::avx2::Bcmp<32>::head_tail(p1, p2, count);
if (count <= 128)
return x86::avx512bw::Bcmp<64>::head_tail(p1, p2, count);
if (LIBC_UNLIKELY(count >= 256)) {
if (auto value = x86::avx512bw::Bcmp<64>::block(p1, p2))
return value;
align_to_next_boundary<64, Arg::P1>(p1, p2, count);
}
return x86::avx512bw::Bcmp<64>::loop_and_tail(p1, p2, count);
}
[[maybe_unused]] LIBC_INLINE BcmpReturnType inline_bcmp_x86(CPtr p1, CPtr p2,
size_t count) {
if (count == 0)
return BcmpReturnType::ZERO();
if (count == 1)
return generic::Bcmp<1>::block(p1, p2);
if (count == 2)
return generic::Bcmp<2>::block(p1, p2);
if (count <= 4)
return generic::Bcmp<2>::head_tail(p1, p2, count);
if (count <= 8)
return generic::Bcmp<4>::head_tail(p1, p2, count);
if (count <= 16)
return generic::Bcmp<8>::head_tail(p1, p2, count);
if constexpr (x86::kAvx512BW)
return inline_bcmp_x86_avx512bw_gt16(p1, p2, count);
else if constexpr (x86::kAvx2)
return inline_bcmp_x86_avx2_gt16(p1, p2, count);
else if constexpr (x86::kSse2)
return inline_bcmp_x86_sse2_gt16(p1, p2, count);
else
return inline_bcmp_generic_gt16(p1, p2, count);
}
#endif // defined(LIBC_TARGET_ARCH_IS_X86)
#if defined(LIBC_TARGET_ARCH_IS_AARCH64)
[[maybe_unused]] LIBC_INLINE BcmpReturnType inline_bcmp_aarch64(CPtr p1,
CPtr p2,
size_t count) {
if (LIBC_LIKELY(count <= 32)) {
if (LIBC_UNLIKELY(count >= 16)) {
return aarch64::Bcmp<16>::head_tail(p1, p2, count);
}
switch (count) {
case 0:
return BcmpReturnType::ZERO();
case 1:
return generic::Bcmp<1>::block(p1, p2);
case 2:
return generic::Bcmp<2>::block(p1, p2);
case 3:
return generic::Bcmp<2>::head_tail(p1, p2, count);
case 4:
return generic::Bcmp<4>::block(p1, p2);
case 5:
case 6:
case 7:
return generic::Bcmp<4>::head_tail(p1, p2, count);
case 8:
return generic::Bcmp<8>::block(p1, p2);
case 9:
case 10:
case 11:
case 12:
case 13:
case 14:
case 15:
return generic::Bcmp<8>::head_tail(p1, p2, count);
}
}
if (count <= 64)
return aarch64::Bcmp<32>::head_tail(p1, p2, count);
// Aligned loop if > 256, otherwise normal loop
if (LIBC_UNLIKELY(count > 256)) {
if (auto value = aarch64::Bcmp<32>::block(p1, p2))
return value;
align_to_next_boundary<16, Arg::P1>(p1, p2, count);
}
return aarch64::Bcmp<32>::loop_and_tail(p1, p2, count);
}
#endif // defined(LIBC_TARGET_ARCH_IS_AARCH64)
LIBC_INLINE BcmpReturnType inline_bcmp(CPtr p1, CPtr p2, size_t count) {
#if defined(LIBC_TARGET_ARCH_IS_X86)
return inline_bcmp_x86(p1, p2, count);
#elif defined(LIBC_TARGET_ARCH_IS_AARCH64)
return inline_bcmp_aarch64(p1, p2, count);
#elif defined(LIBC_TARGET_ARCH_IS_RISCV64)
return inline_bcmp_aligned_access_64bit(p1, p2, count);
#elif defined(LIBC_TARGET_ARCH_IS_RISCV32)
return inline_bcmp_aligned_access_32bit(p1, p2, count);
#else
return inline_bcmp_byte_per_byte(p1, p2, 0, count);
#endif
}
LIBC_INLINE int inline_bcmp(const void *p1, const void *p2, size_t count) {
return static_cast<int>(inline_bcmp(reinterpret_cast<CPtr>(p1),
reinterpret_cast<CPtr>(p2), count));
}
} // namespace __llvm_libc
#endif // LLVM_LIBC_SRC_STRING_MEMORY_UTILS_BCMP_IMPLEMENTATIONS_H
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