/**
* 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);
}
}
}
}
@Inline
private static void copy2Bytes(Address dstPtr, Address srcPtr) {
dstPtr.store(srcPtr.loadChar());
}