let t : integer{} = UInt(Rt); let n : integer{} = UInt(Rn); let nontemporal : boolean = FALSE; let tagchecked : boolean = wback || n != 31; var c : Constraint; var rt_unknown : boolean = FALSE; if wback && n == t && n != 31 then c = ConstrainUnpredictable(Unpredictable_WBOVERLAPST); assert c IN {Constraint_NONE, Constraint_UNKNOWN, Constraint_UNDEF, Constraint_NOP}; case c of when Constraint_NONE => rt_unknown = FALSE; // Value stored is original value when Constraint_UNKNOWN => rt_unknown = TRUE; // Value stored is UNKNOWN when Constraint_UNDEF => EndOfDecode(Decode_UNDEF); when Constraint_NOP => EndOfDecode(Decode_NOP); end; end;

var address : bits(64); let privileged : boolean = PSTATE.EL != EL0; let accdesc : AccessDescriptor = CreateAccDescGPR(MemOp_STORE, nontemporal, privileged, tagchecked, t); if n == 31 then CheckSPAlignment(); address = SP{64}(); else address = X{64}(n); end; if !postindex then address = AddressAdd(address, offset, accdesc); end; var data : bits(16); if rt_unknown then data = ARBITRARY : bits(16); else data = X{16}(t); end; Mem{16}(address, accdesc) = data; if wback then if postindex then address = AddressAdd(address, offset, accdesc); end; if n == 31 then SP{64}() = address; else X{64}(n) = address; end; end;