def allocate(ctx, mh_addr, num_bytes):
# nothing to allocate
if num_bytes == 0:
return 0
# round size to nearest 8 byte
ex = num_bytes & 7
if ex != 0:
num_bytes += 8 - ex
# read mem header
mh = MemHdr()
mh.read(ctx, mh_addr)
log_exec.debug("read: %s", mh)
# enough total free?
if mh.free < num_bytes:
return 0
if mh.first == 0:
return 0
# find chunk with enough free bytes
mc_last = None
mc = mh.read_first(ctx)
log_exec.debug("read: %s", mc)
while mc.bytes < num_bytes:
mc_next = mc.read_next(ctx)
log_exec.debug("read: %s", mc_next)
if mc_next is None:
log_exec.warn("invalid mem chunk list!")
return 0
mc_last = mc
mc = mc_next
# what's left in chunk?
rem = mc.bytes - num_bytes
if rem > 0:
# some bytes left in chunk -> adjust size and keep it
mc.bytes = rem
mc.write(ctx)
# allocate at end of chunk
res_addr = mc.addr + rem
log_exec.debug("shrink: %s", mc)
else:
# remove whole chunk
if mc_last is None:
# set new first
mh.first = mc.next
# mh will be written below
else:
mc_last.next = mc.next
mc_last.write(ctx)
# result is whole chunk
res_addr = mc.addr
log_exec.debug("remove: %s", mc)
# update header
mh.free -= num_bytes
mh.write(ctx)
log_exec.debug("done: %s", mh)
return res_addr
def allocate(ctx, mh_addr, num_bytes):
# nothing to allocate
if num_bytes == 0:
return 0
# round size to nearest 8 byte
ex = num_bytes & 7
if ex != 0:
num_bytes += 8 - ex
# read mem header
mh = MemHdr()
mh.read(ctx, mh_addr)
log_exec.debug("read: %s", mh)
# enough total free?
if mh.free < num_bytes:
return 0
if mh.first == 0:
return 0
# find chunk with enough free bytes
mc_last = None
mc = mh.read_first(ctx)
log_exec.debug("read: %s", mc)
while mc.bytes < num_bytes:
mc_next = mc.read_next(ctx)
log_exec.debug("read: %s", mc_next)
if mc_next is None:
log_exec.warn("invalid mem chunk list!")
return 0
mc_last = mc
mc = mc_next
# what's left in chunk?
rem = mc.bytes - num_bytes
if rem > 0:
# some bytes left in chunk -> adjust size and keep it
mc.bytes = rem
mc.write(ctx)
# allocate at end of chunk
res_addr = mc.addr + rem
log_exec.debug("shrink: %s", mc)
else:
# remove whole chunk
if mc_last is None:
# set new first
mh.first = mc.next
# mh will be written below
else:
mc_last.next = mc.next
mc_last.write(ctx)
# result is whole chunk
res_addr = mc.addr
log_exec.debug("remove: %s", mc)
# update header
mh.free -= num_bytes
mh.write(ctx)
log_exec.debug("done: %s", mh)
return res_addr
def deallocate(ctx, mh_addr, blk_addr, num_bytes):
# nothing to allocate
if num_bytes == 0 or blk_addr == 0:
return 0
# round size to nearest 8 byte
ex = num_bytes & 7
if ex != 0:
num_bytes += 8 - ex
# read mem header
mh = MemHdr()
mh.read(ctx, mh_addr)
log_exec.debug("read: %s", mh)
# no mem chunks?
if mh.first == 0:
# assume that the whole memory is returned
if num_bytes != mh.total or blk_addr != mh.lower or mh.free != 0:
log_exec.error("Invalid deallocation: num_bytes != mh.total")
# create a new mc
mc = MemChunk(0, num_bytes, mh.lower)
mc.write(ctx)
log_exec.debug("single: %s", mc)
mh.first = mh.lower
else:
# find chunk right before/after the returned block
mc_last = None
mc = mh.read_first(ctx)
log_exec.debug("read: %s", mc)
while mc and mc.addr < blk_addr:
mc_last = mc
mc = mc.read_next(ctx)
if mc is not None:
log_exec.debug("read: %s", mc)
# now we have either a mc_last and/or mc chunk
# check if we can merge with one or both
end_addr = blk_addr + num_bytes
mc_merge = True if mc is not None and end_addr == mc.addr else False
mc_last_merge = True if mc_last is not None and mc_last.addr + mc_last.bytes == blk_addr else False
log_exec.debug("merge: mc_last=%s, mc=%s", mc_last_merge, mc_merge)
# we merge with both last and current one -> grow mc_last, remove mc
if mc_merge and mc_last_merge:
mc_last.bytes += num_bytes + mc.bytes
mc_last.next = mc.next
mc_last.write(ctx)
log_exec.debug("both: %s", mc_last)
# we merge with last only
elif mc_last_merge:
mc_last.bytes += num_bytes
mc_last.write(ctx)
log_exec.debug("grow last: %s", mc_last)
# we merge with current only -> move chunk to begin of blk_addr
elif mc_merge:
mc.addr = blk_addr
mc.bytes += num_bytes
mc.write(ctx)
mc_last.next = blk_addr
mc_last.write(ctx)
log_exec.debug("grow cur: %s", mc)
# no merging possible -> create a new chunk between last and cur
else:
next_addr = mc.addr if mc is not None else 0
mc_new = MemChunk(next_addr, num_bytes, blk_addr)
mc_new.write(ctx)
if mc_last is not None:
mc_last.next = mc_new.addr
mc_last.write(ctx)
log_exec.debug("new after: %s", mc_new)
else:
mh.first = mc_new.addr
# mh is written below
log_exec.debug("new front: %s", mc_new)
# update header
mh.free += num_bytes
mh.write(ctx)
log_exec.debug("done: %s", mh)
def deallocate(ctx, mh_addr, blk_addr, num_bytes):
# nothing to allocate
if num_bytes == 0 or blk_addr == 0:
return 0
# round size to nearest 8 byte
ex = num_bytes & 7
if ex != 0:
num_bytes += 8 - ex
# read mem header
mh = MemHdr()
mh.read(ctx, mh_addr)
log_exec.debug("read: %s", mh)
# no mem chunks?
if mh.first == 0:
# assume that the whole memory is returned
if num_bytes != mh.total or blk_addr != mh.lower or mh.free != 0:
log_exec.error("Invalid deallocation: num_bytes != mh.total")
# create a new mc
mc = MemChunk(0, num_bytes, mh.lower)
mc.write(ctx)
log_exec.debug("single: %s", mc)
mh.first = mh.lower
else:
# find chunk right before/after the returned block
mc_last = None
mc = mh.read_first(ctx)
log_exec.debug("read: %s", mc)
while mc and mc.addr < blk_addr:
mc_last = mc
mc = mc.read_next(ctx)
if mc is not None:
log_exec.debug("read: %s", mc)
# now we have either a mc_last and/or mc chunk
# check if we can merge with one or both
end_addr = blk_addr + num_bytes
mc_merge = True if mc is not None and end_addr == mc.addr else False
mc_last_merge = True if mc_last is not None and mc_last.addr + mc_last.bytes == blk_addr else False
log_exec.debug("merge: mc_last=%s, mc=%s", mc_last_merge, mc_merge)
# we merge with both last and current one -> grow mc_last, remove mc
if mc_merge and mc_last_merge:
mc_last.bytes += num_bytes + mc.bytes
mc_last.next = mc.next
mc_last.write(ctx)
log_exec.debug("both: %s", mc_last)
# we merge with last only
elif mc_last_merge:
mc_last.bytes += num_bytes
mc_last.write(ctx)
log_exec.debug("grow last: %s", mc_last)
# we merge with current only -> move chunk to begin of blk_addr
elif mc_merge:
mc.addr = blk_addr
mc.bytes += num_bytes
mc.write(ctx)
mc_last.next = blk_addr
mc_last.write(ctx)
log_exec.debug("grow cur: %s", mc)
# no merging possible -> create a new chunk between last and cur
else:
next_addr = mc.addr if mc is not None else 0
mc_new = MemChunk(next_addr, num_bytes, blk_addr)
mc_new.write(ctx)
if mc_last is not None:
mc_last.next = mc_new.addr
mc_last.write(ctx)
log_exec.debug("new after: %s", mc_new)
else:
mh.first = mc_new.addr
# mh is written below
log_exec.debug("new front: %s", mc_new)
# update header
mh.free += num_bytes
mh.write(ctx)
log_exec.debug("done: %s", mh)
