コード例 #1
0
ファイル: VM_Memory.java プロジェクト: rmcilroy/HeraJVM
  /**
   * Low level copy of len elements from src[srcPos] to dst[dstPos].
   *
   * <p>Assumption src != dst || (srcPos >= dstPos + 2).
   *
   * @param src the source array
   * @param srcPos index in the source array to begin copy
   * @param dst the destination array
   * @param dstPos index in the destination array to being copy
   * @param len number of array elements to copy
   */
  @Inline
  public static void arraycopy16Bit(Object src, int srcPos, Object dst, int dstPos, int len) {
    if (USE_NATIVE && len > (NATIVE_THRESHOLD >> LOG_BYTES_IN_SHORT)) {
      memcopy(
          VM_Magic.objectAsAddress(dst).plus(dstPos << LOG_BYTES_IN_SHORT),
          VM_Magic.objectAsAddress(src).plus(srcPos << LOG_BYTES_IN_SHORT),
          len << LOG_BYTES_IN_SHORT);
    } else {
      if (len >= (BYTES_IN_ADDRESS >>> LOG_BYTES_IN_SHORT)
          && (srcPos & ((BYTES_IN_ADDRESS - 1) >>> LOG_BYTES_IN_SHORT))
              == (dstPos & ((BYTES_IN_ADDRESS - 1) >>> LOG_BYTES_IN_SHORT))) {
        // relative alignment is the same
        int byteStart = srcPos << LOG_BYTES_IN_SHORT;
        int wordStart = alignUp(byteStart, BYTES_IN_ADDRESS);
        int wordEnd = alignDown(byteStart + (len << LOG_BYTES_IN_SHORT), BYTES_IN_ADDRESS);
        int byteEnd = byteStart + (len << LOG_BYTES_IN_SHORT);
        int startDiff = wordStart - byteStart;
        int endDiff = byteEnd - wordEnd;
        int wordLen = wordEnd - wordStart;
        Address srcPtr =
            VM_Magic.objectAsAddress(src).plus((srcPos << LOG_BYTES_IN_SHORT) + startDiff);
        Address dstPtr =
            VM_Magic.objectAsAddress(dst).plus((dstPos << LOG_BYTES_IN_SHORT) + startDiff);

        if (VM.BuildFor64Addr) {
          switch (startDiff) {
            case 6:
              dstPtr.store(
                  srcPtr.loadChar(Offset.fromIntSignExtend(-6)), Offset.fromIntSignExtend(-6));
            case 4:
              dstPtr.store(
                  srcPtr.loadChar(Offset.fromIntSignExtend(-4)), Offset.fromIntSignExtend(-4));
            case 2:
              dstPtr.store(
                  srcPtr.loadChar(Offset.fromIntSignExtend(-2)), Offset.fromIntSignExtend(-2));
          }
        } else {
          if (startDiff == 2) {
            dstPtr.store(
                srcPtr.loadChar(Offset.fromIntSignExtend(-2)), Offset.fromIntSignExtend(-2));
          }
        }

        Address endPtr = srcPtr.plus(wordLen);
        while (srcPtr.LT(endPtr)) {
          dstPtr.store(srcPtr.loadWord());
          srcPtr = srcPtr.plus(BYTES_IN_ADDRESS);
          dstPtr = dstPtr.plus(BYTES_IN_ADDRESS);
        }

        if (VM.BuildFor64Addr) {
          switch (endDiff) {
            case 6:
              dstPtr.store(
                  srcPtr.loadChar(Offset.fromIntSignExtend(4)), Offset.fromIntSignExtend(4));
            case 4:
              dstPtr.store(
                  srcPtr.loadChar(Offset.fromIntSignExtend(2)), Offset.fromIntSignExtend(2));
            case 2:
              dstPtr.store(srcPtr.loadChar());
          }
        } else {
          if (endDiff == 2) {
            dstPtr.store(srcPtr.loadChar());
          }
        }

      } else {
        Address srcPtr = VM_Magic.objectAsAddress(src).plus(srcPos << LOG_BYTES_IN_CHAR);
        Address dstPtr = VM_Magic.objectAsAddress(dst).plus(dstPos << LOG_BYTES_IN_CHAR);
        Address endPtr = srcPtr.plus(len << LOG_BYTES_IN_CHAR);
        while (srcPtr.LT(endPtr)) {
          dstPtr.store(srcPtr.loadChar());
          srcPtr = srcPtr.plus(2);
          dstPtr = dstPtr.plus(2);
        }
      }
    }
  }
コード例 #2
0
 @Inline
 private static void copy2Bytes(Address dstPtr, Address srcPtr) {
   dstPtr.store(srcPtr.loadChar());
 }