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 /*

  * Copyright (c) 2006, 2018, 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 "runtime/sharedRuntime.hpp"

 #include "utilities/copy.hpp"

 // Copy bytes; larger units are filled atomically if everything is aligned.

 void Copy::conjoint_memory_atomic(void* from, void* to, size_t size) {

   address src = (address) from;

   address dst = (address) to;

   uintptr_t bits = (uintptr_t) src | (uintptr_t) dst | (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((jlong*) src, (jlong*) dst, size / sizeof(jlong));

   } else if (bits % sizeof(jint) == 0) {

     Copy::conjoint_jints_atomic((jint*) src, (jint*) dst, size / sizeof(jint));

   } else if (bits % sizeof(jshort) == 0) {

     Copy::conjoint_jshorts_atomic((jshort*) src, (jshort*) dst, size / sizeof(jshort));

   } else {

     // Not aligned, so no need to be atomic.

     Copy::conjoint_jbytes((void*) src, (void*) dst, size);

   }

 }

 class CopySwap : AllStatic {

 public:

   /**

    * Copy and byte swap elements

    *

    * @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

    */

   static void conjoint_swap(address src, address 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,

            err_msg("incorrect element size: " SIZE_FORMAT, elem_size));

     assert(is_size_aligned(byte_count, elem_size),

            err_msg("byte_count " SIZE_FORMAT " must be multiple of element size " SIZE_FORMAT, byte_count, elem_size));

     address src_end = src + byte_count;

     if (dst <= src || dst >= src_end) {

       do_conjoint_swap<RIGHT>(src, dst, byte_count, elem_size);

     } else {

       do_conjoint_swap<LEFT>(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 is_src_aligned, bool is_dst_aligned>

   static void do_conjoint_swap(address src, address dst, size_t byte_count) {

     address cur_src, cur_dst;

     switch (D) {

     case RIGHT:

       cur_src = src;

       cur_dst = dst;

       break;

     case LEFT:

       cur_src = src + byte_count - sizeof(T);

       cur_dst = 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));

       }

       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

    *

    * @param src address of source

    * @param dst address of destination

    * @param byte_count number of bytes to copy

    */

   template <typename T, CopyDirection direction>

   static void do_conjoint_swap(address src, address dst, size_t byte_count) {

     if (is_ptr_aligned(src, sizeof(T))) {

       if (is_ptr_aligned(dst, sizeof(T))) {

         do_conjoint_swap<T,direction,true,true>(src, dst, byte_count);

       } else {

         do_conjoint_swap<T,direction,true,false>(src, dst, byte_count);

       }

     } else {

       if (is_ptr_aligned(dst, sizeof(T))) {

         do_conjoint_swap<T,direction,false,true>(src, dst, byte_count);

       } else {

         do_conjoint_swap<T,direction,false,false>(src, dst, byte_count);

       }

     }

   }

   /**

    * Copy and byte swap elements

    *

    * <D> - copy direction

    *

    * @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>

   static void do_conjoint_swap(address src, address dst, size_t byte_count, size_t elem_size) {

     switch (elem_size) {

     case 2: do_conjoint_swap<uint16_t,D>(src, dst, byte_count); break;

     case 4: do_conjoint_swap<uint32_t,D>(src, dst, byte_count); break;

     case 8: do_conjoint_swap<uint64_t,D>(src, dst, byte_count); break;

     default: guarantee(false, err_msg("do_conjoint_swap: Invalid elem_size %zd\n", elem_size));

     }

   }

 };

 void Copy::conjoint_swap(address src, address dst, size_t byte_count, size_t elem_size) {

   CopySwap::conjoint_swap(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);

   }

 }