setpsr
#define trapoff() do { setpsr(getpsr() & ~PSR_ET); } while(0)
#define trapon() do { setpsr(getpsr() | PSR_ET); } while(0)
setpsr(opsr); /* turn traps on again */
setpsr(getpsr() & ~PSR_EF);
setpsr(getpsr() & ~PSR_EF);
setpsr(getpsr() & ~PSR_EF);
setpsr(getpsr() & ~PSR_EF);