Atomically Modify a Table Value

#Threads

v = atomic.modify(t, idx, mask, inc)

Modifies t[idx] by applying a bit mask and increment value inc.
Returns v as the original value.

e.g.

  • atomic.modify(t, 'x', 0, 1) - increments t.x
  • atomic.modify(t, 'x', 0, -1) - decrements t.x
  • atomic.modify(t, 'y', -1, 123) - sets t.y to 123

The mask and increment operation in C:

v = (v & ~mask) + inc;