mov psr.um Operation Font Conventions
if (PR[qp]) {
if (from_form) {
check_target_register;

GR[r1] = zero_ext(PSR{5:0}, 6);
GR[r1].nat = 0;
} else { // to_form
if (GR[r2].nat)
register_nat_consumption_fault(0);

if (is_reserved_field(PSR_TYPE, PSR_UM, GR[r2]))
reserved_register_field_fault();

PSR{1:0} = GR[r2]{1:0};

if (PSR.sp == 0) // unsecured perf monitor
PSR{2} = GR[r2]{2};

PSR{5:3} = GR[r2]{5:3};
}
}