Sp(3) = exception; // the AP_STACK
Sp(2) = base_GHCziBase_True_closure; // dummy breakpoint info
Sp(1) = base_GHCziBase_True_closure; // True <=> a breakpoint
R1 = ioAction;
Sp(3) = exception; // the AP_STACK
Sp(2) = base_GHCziBase_True_closure; // dummy breakpoint info
Sp(1) = base_GHCziBase_True_closure; // True <=> a breakpoint
R1 = ioAction;