$80:83AE

From ZAMN Hacking
ROM address data
Length 0x27
Type Code
Name runOnVBLANK
Description Creates a VBLANK listener
Arguments/Return value Y+A = [pointer32] Listener subroutine
Returns X = [uint16] Listener ID
Return type RTL

The given subroutine returns a value in the carry indicating if it should continue to run on the next frame.