newPinnedByteArrayzh_fast
{
- W_ words, payload_words, n, p;
+ W_ words, bytes, payload_words, p;
MAYBE_GC(NO_PTRS,newPinnedByteArrayzh_fast);
- n = R1;
- payload_words = ROUNDUP_BYTES_TO_WDS(n);
-
- words = payload_words + ((SIZEOF_StgArrWords + BA_MASK) & ~BA_MASK);
+ bytes = R1;
+ /* payload_words is what we will tell the profiler we had to allocate */
+ payload_words = ROUNDUP_BYTES_TO_WDS(bytes);
+ /* When we actually allocate memory, we need to allow space for the
+ header: */
+ bytes = bytes + SIZEOF_StgArrWords;
+ /* And we want to align to BA_ALIGN bytes, so we need to allow space
+ to shift up to BA_ALIGN - 1 bytes: */
+ bytes = bytes + BA_ALIGN - 1;
+ /* Now we convert to a number of words: */
+ words = ROUNDUP_BYTES_TO_WDS(bytes);
("ptr" p) = foreign "C" allocatePinned(words) [];
TICK_ALLOC_PRIM(SIZEOF_StgArrWords,WDS(payload_words),0);
- // This bumps p forwards so that the payload falls on an R2-byte boundary.
+ /* Now we need to move p forward so that the payload is aligned
+ to BA_ALIGN bytes: */
p = p + ((-p - SIZEOF_StgArrWords) & BA_MASK);
SET_HDR(p, stg_ARR_WORDS_info, W_[CCCS]);
newAlignedPinnedByteArrayzh_fast
{
- W_ words, payload_words, n, p, mask;
+ W_ words, bytes, payload_words, p, alignment;
MAYBE_GC(NO_PTRS,newAlignedPinnedByteArrayzh_fast);
- n = R1;
+ bytes = R1;
+ alignment = R2;
- if (R2 > SIZEOF_W) {
- mask = R2 - 1;
- } else {
- mask = 0;
- }
-
- payload_words = ROUNDUP_BYTES_TO_WDS(n);
+ /* payload_words is what we will tell the profiler we had to allocate */
+ payload_words = ROUNDUP_BYTES_TO_WDS(bytes);
- // We want an <align>-byte aligned array. allocatePinned() gives us
- // 8-byte aligned memory by default, but we want to align the
- // *goods* inside the ArrWords object, so we have to check the
- // size of the ArrWords header and adjust our size accordingly.
- words = payload_words + ((SIZEOF_StgArrWords + mask) & ~mask);
+ /* When we actually allocate memory, we need to allow space for the
+ header: */
+ bytes = bytes + SIZEOF_StgArrWords;
+ /* And we want to align to <alignment> bytes, so we need to allow space
+ to shift up to <alignment - 1> bytes: */
+ bytes = bytes + alignment - 1;
+ /* Now we convert to a number of words: */
+ words = ROUNDUP_BYTES_TO_WDS(bytes);
("ptr" p) = foreign "C" allocatePinned(words) [];
TICK_ALLOC_PRIM(SIZEOF_StgArrWords,WDS(payload_words),0);
- // This bumps p forwards so that the payload falls on an R2-byte boundary.
- p = p + ((-p - SIZEOF_StgArrWords) & mask);
+ /* Now we need to move p forward so that the payload is aligned
+ to <alignment> bytes. Note that we are assuming that
+ <alignment> is a power of 2, which is technically not guaranteed */
+ p = p + ((-p - SIZEOF_StgArrWords) & (alignment - 1));
SET_HDR(p, stg_ARR_WORDS_info, W_[CCCS]);
StgArrWords_words(p) = payload_words;
foreign "C" scheduleThread(MyCapability() "ptr", threadid "ptr") [];
- // switch at the earliest opportunity
+ // context switch soon, but not immediately: we don't want every
+ // forkIO to force a context-switch.
Capability_context_switch(MyCapability()) = 1 :: CInt;
RET_P(threadid);
foreign "C" scheduleThreadOn(MyCapability() "ptr", cpu, threadid "ptr") [];
- // switch at the earliest opportunity
+ // context switch soon, but not immediately: we don't want every
+ // forkIO to force a context-switch.
Capability_context_switch(MyCapability()) = 1 :: CInt;
RET_P(threadid);