inline bool lock_threadid(INT32 threadid)
{
INT32 prev_id;
prev_id = compare_exchange32(&m_threadid, -1, threadid);
return (prev_id == -1 && m_threadid == threadid);
}
static void *poly_item_callback(void *param, int threadid)
{
while (1)
{
work_unit *unit = (work_unit *)param;
polygon_info *polygon = unit->shared.polygon;
int count = unit->shared.count_next & 0xffff;
UINT32 orig_count_next;
int curscan;
/* if our previous item isn't done yet, enqueue this item to the end and proceed */
if (unit->shared.previtem != 0xffff)
{
work_unit *prevunit = polygon->poly->unit[unit->shared.previtem];
if (prevunit->shared.count_next != 0)
{
UINT32 unitnum = ((UINT8 *)unit - (UINT8 *)polygon->poly->unit[0]) / polygon->poly->unit_size;
UINT32 new_count_next;
/* attempt to atomically swap in this new value */
do
{
orig_count_next = prevunit->shared.count_next;
new_count_next = orig_count_next | (unitnum << 16);
} while (compare_exchange32((volatile INT32 *)&prevunit->shared.count_next, orig_count_next, new_count_next) != orig_count_next);
#if KEEP_STATISTICS
/* track resolved conflicts */
polygon->poly->conflicts[threadid]++;
if (orig_count_next != 0)
polygon->poly->resolved[threadid]++;
#endif
/* if we succeeded, skip out early so we can do other work */
if (orig_count_next != 0)
break;
}
}
/* iterate over extents */
for (curscan = 0; curscan < count; curscan++)
{
if (polygon->numverts == 3)
{
poly_extent tmpextent;
convert_tri_extent_to_poly_extent(&tmpextent, &unit->tri.extent[curscan], polygon, unit->shared.scanline + curscan);
(*polygon->callback)(polygon->dest, unit->shared.scanline + curscan, &tmpextent, polygon->extra, threadid);
}
else
(*polygon->callback)(polygon->dest, unit->shared.scanline + curscan, &unit->quad.extent[curscan], polygon->extra, threadid);
}
/* set our count to 0 and re-fetch the original count value */
do
{
orig_count_next = unit->shared.count_next;
} while (compare_exchange32((volatile INT32 *)&unit->shared.count_next, orig_count_next, 0) != orig_count_next);
/* if we have no more work to do, do nothing */
orig_count_next >>= 16;
if (orig_count_next == 0)
break;
param = polygon->poly->unit[orig_count_next];
}
return NULL;
}
