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/*
* Copyright (c) 2006, 2020, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "utilities/copy.hpp"
#include "runtime/sharedRuntime.hpp"
#include "utilities/align.hpp"
#include "utilities/copy.hpp"
// Copy bytes; larger units are filled atomically if everything is aligned.
void Copy::conjoint_memory_atomic(const void* from, void* to, size_t size) {
uintptr_t bits = (uintptr_t) from | (uintptr_t) to | (uintptr_t) size;
// (Note: We could improve performance by ignoring the low bits of size,
// and putting a short cleanup loop after each bulk copy loop.
// There are plenty of other ways to make this faster also,
// and it's a slippery slope. For now, let's keep this code simple
// since the simplicity helps clarify the atomicity semantics of
// this operation. There are also CPU-specific assembly versions
// which may or may not want to include such optimizations.)
if (bits % sizeof(jlong) == 0) {
Copy::conjoint_jlongs_atomic((const jlong*) from, (jlong*) to, size / sizeof(jlong));
} else if (bits % sizeof(jint) == 0) {
Copy::conjoint_jints_atomic((const jint*) from, (jint*) to, size / sizeof(jint));
} else if (bits % sizeof(jshort) == 0) {
Copy::conjoint_jshorts_atomic((const jshort*) from, (jshort*) to, size / sizeof(jshort));
} else {
// Not aligned, so no need to be atomic.
Copy::conjoint_jbytes((const void*) from, (void*) to, size);
}
}
class CopySwap : AllStatic {
public:
/**
* Copy and optionally byte swap elements
*
* <swap> - true if elements should be byte swapped
*
* @param src address of source
* @param dst address of destination
* @param byte_count number of bytes to copy
* @param elem_size size of the elements to copy-swap
*/
template<bool swap>
static void conjoint_swap_if_needed(const void* src, void* dst, size_t byte_count, size_t elem_size) {
assert(src != NULL, "address must not be NULL");
assert(dst != NULL, "address must not be NULL");
assert(elem_size == 2 || elem_size == 4 || elem_size == 8,
"incorrect element size: " SIZE_FORMAT, elem_size);
assert(is_aligned(byte_count, elem_size),
"byte_count " SIZE_FORMAT " must be multiple of element size " SIZE_FORMAT, byte_count, elem_size);
address src_end = (address)src + byte_count;
if (dst <= src || dst >= src_end) {
do_conjoint_swap<RIGHT,swap>(src, dst, byte_count, elem_size);
} else {
do_conjoint_swap<LEFT,swap>(src, dst, byte_count, elem_size);
}
}
private:
/**
* Byte swap a 16-bit value
*/
static uint16_t byte_swap(uint16_t x) {
return (x << 8) | (x >> 8);
}
/**
* Byte swap a 32-bit value
*/
static uint32_t byte_swap(uint32_t x) {
uint16_t lo = (uint16_t)x;
uint16_t hi = (uint16_t)(x >> 16);
return ((uint32_t)byte_swap(lo) << 16) | (uint32_t)byte_swap(hi);
}
/**
* Byte swap a 64-bit value
*/
static uint64_t byte_swap(uint64_t x) {
uint32_t lo = (uint32_t)x;
uint32_t hi = (uint32_t)(x >> 32);
return ((uint64_t)byte_swap(lo) << 32) | (uint64_t)byte_swap(hi);
}
enum CopyDirection {
RIGHT, // lower -> higher address
LEFT // higher -> lower address
};
/**
* Copy and byte swap elements
*
* <T> - type of element to copy
* <D> - copy direction
* <is_src_aligned> - true if src argument is aligned to element size
* <is_dst_aligned> - true if dst argument is aligned to element size
*
* @param src address of source
* @param dst address of destination
* @param byte_count number of bytes to copy
*/
template <typename T, CopyDirection D, bool swap, bool is_src_aligned, bool is_dst_aligned>
static void do_conjoint_swap(const void* src, void* dst, size_t byte_count) {
const char* cur_src;
char* cur_dst;
switch (D) {
case RIGHT:
cur_src = (const char*)src;
cur_dst = (char*)dst;
break;
case LEFT:
cur_src = (const char*)src + byte_count - sizeof(T);
cur_dst = (char*)dst + byte_count - sizeof(T);
break;
}
for (size_t i = 0; i < byte_count / sizeof(T); i++) {
T tmp;
if (is_src_aligned) {
tmp = *(T*)cur_src;
} else {
memcpy(&tmp, cur_src, sizeof(T));
}
if (swap) {
tmp = byte_swap(tmp);
}
if (is_dst_aligned) {
*(T*)cur_dst = tmp;
} else {
memcpy(cur_dst, &tmp, sizeof(T));
}
switch (D) {
case RIGHT:
cur_src += sizeof(T);
cur_dst += sizeof(T);
break;
case LEFT:
cur_src -= sizeof(T);
cur_dst -= sizeof(T);
break;
}
}
}
/**
* Copy and byte swap elements
*
* <T> - type of element to copy
* <D> - copy direction
* <swap> - true if elements should be byte swapped
*
* @param src address of source
* @param dst address of destination
* @param byte_count number of bytes to copy
*/
template <typename T, CopyDirection direction, bool swap>
static void do_conjoint_swap(const void* src, void* dst, size_t byte_count) {
if (is_aligned(src, sizeof(T))) {
if (is_aligned(dst, sizeof(T))) {
do_conjoint_swap<T,direction,swap,true,true>(src, dst, byte_count);
} else {
do_conjoint_swap<T,direction,swap,true,false>(src, dst, byte_count);
}
} else {
if (is_aligned(dst, sizeof(T))) {
do_conjoint_swap<T,direction,swap,false,true>(src, dst, byte_count);
} else {
do_conjoint_swap<T,direction,swap,false,false>(src, dst, byte_count);
}
}
}
/**
* Copy and byte swap elements
*
* <D> - copy direction
* <swap> - true if elements should be byte swapped
*
* @param src address of source
* @param dst address of destination
* @param byte_count number of bytes to copy
* @param elem_size size of the elements to copy-swap
*/
template <CopyDirection D, bool swap>
static void do_conjoint_swap(const void* src, void* dst, size_t byte_count, size_t elem_size) {
switch (elem_size) {
case 2: do_conjoint_swap<uint16_t,D,swap>(src, dst, byte_count); break;
case 4: do_conjoint_swap<uint32_t,D,swap>(src, dst, byte_count); break;
case 8: do_conjoint_swap<uint64_t,D,swap>(src, dst, byte_count); break;
default: guarantee(false, "do_conjoint_swap: Invalid elem_size " SIZE_FORMAT "\n", elem_size);
}
}
};
void Copy::conjoint_copy(const void* src, void* dst, size_t byte_count, size_t elem_size) {
CopySwap::conjoint_swap_if_needed<false>(src, dst, byte_count, elem_size);
}
void Copy::conjoint_swap(const void* src, void* dst, size_t byte_count, size_t elem_size) {
CopySwap::conjoint_swap_if_needed<true>(src, dst, byte_count, elem_size);
}
// Fill bytes; larger units are filled atomically if everything is aligned.
void Copy::fill_to_memory_atomic(void* to, size_t size, jubyte value) {
address dst = (address) to;
uintptr_t bits = (uintptr_t) to | (uintptr_t) size;
if (bits % sizeof(jlong) == 0) {
jlong fill = (julong)( (jubyte)value ); // zero-extend
if (fill != 0) {
fill += fill << 8;
fill += fill << 16;
fill += fill << 32;
}
//Copy::fill_to_jlongs_atomic((jlong*) dst, size / sizeof(jlong));
for (uintptr_t off = 0; off < size; off += sizeof(jlong)) {
*(jlong*)(dst + off) = fill;
}
} else if (bits % sizeof(jint) == 0) {
jint fill = (juint)( (jubyte)value ); // zero-extend
if (fill != 0) {
fill += fill << 8;
fill += fill << 16;
}
//Copy::fill_to_jints_atomic((jint*) dst, size / sizeof(jint));
for (uintptr_t off = 0; off < size; off += sizeof(jint)) {
*(jint*)(dst + off) = fill;
}
} else if (bits % sizeof(jshort) == 0) {
jshort fill = (jushort)( (jubyte)value ); // zero-extend
fill += fill << 8;
//Copy::fill_to_jshorts_atomic((jshort*) dst, size / sizeof(jshort));
for (uintptr_t off = 0; off < size; off += sizeof(jshort)) {
*(jshort*)(dst + off) = fill;
}
} else {
// Not aligned, so no need to be atomic.
Copy::fill_to_bytes(dst, size, value);
}
}
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