TCO Tag Check Override when FEAT_MTE is implemented When FEAT_MTE is implemented, this register allows tag checks to be disabled globally. When FEAT_MTE2 is not implemented, it is IMPLEMENTATION DEFINED if accesses to this register access PSTATE.TCO or are RAZ/WI. PSTATE TCO is a 64-bit register. 63 26 63:26 Reserved, RES0. TCO 25 25 25 Allows memory tag checks to be globally disabled. 0b0 Loads and Stores are not affected by this control. 0b1 Loads and Stores are unchecked. 24 0 24:0 Reserved, RES0. For information about the operation of the MSR (immediate) accessor, see MSR (immediate). MRS <Xt>, TCO if !IsFeatureImplemented(FEAT_MTE) then Undefined(); elsif PSTATE.EL == EL0 then X{64}(t) = Zeros{38} :: PSTATE.TCO :: Zeros{25}; elsif PSTATE.EL == EL1 then X{64}(t) = Zeros{38} :: PSTATE.TCO :: Zeros{25}; elsif PSTATE.EL == EL2 then X{64}(t) = Zeros{38} :: PSTATE.TCO :: Zeros{25}; elsif PSTATE.EL == EL3 then X{64}(t) = Zeros{38} :: PSTATE.TCO :: Zeros{25}; end; MSR TCO, <Xt> if !IsFeatureImplemented(FEAT_MTE) then Undefined(); elsif PSTATE.EL == EL0 then PSTATE.TCO = X{64}(t)[25]; elsif PSTATE.EL == EL1 then PSTATE.TCO = X{64}(t)[25]; elsif PSTATE.EL == EL2 then PSTATE.TCO = X{64}(t)[25]; elsif PSTATE.EL == EL3 then PSTATE.TCO = X{64}(t)[25]; end; MSR TCO, #<imm> 2026-03-26 20:27:25 2026-03_rel