LDURSH
Load register signed halfword (unscaled)
This instruction calculates an
address from a base
register and an immediate offset, loads a signed halfword from memory,
sign-extends it, and writes it
to a register. For information about addressing modes, see
Load/Store addressing modes.
This instruction is a data-independent-time instruction as described in About PSTATE.DIT.
0
1
1
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x
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LDURSH <Wt>, [<Xn|SP>{, #<simm>}]
0
LDURSH <Xt>, [<Xn|SP>{, #<simm>}]
let offset : bits(64) = SignExtend{}(imm9);
<Wt>
Is the 32-bit name of the general-purpose register to be transferred, encoded in the "Rt" field.
<Xn|SP>
Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field.
<simm>
Is the optional signed immediate byte offset, in the range -256 to 255, defaulting to 0 and encoded in the "imm9" field.
<Xt>
Is the 64-bit name of the general-purpose register to be transferred, encoded in the "Rt" field.
let n : integer = UInt(Rn);
let t : integer = UInt(Rt);
let datasize : integer{} = 16;
let regsize : integer{} = 64 >> UInt(opc[0]);
let nontemporal : boolean = FALSE;
let tagchecked : boolean = n != 31;
var address : bits(64);
let privileged : boolean = PSTATE.EL != EL0;
let accdesc : AccessDescriptor = CreateAccDescGPR(MemOp_LOAD, nontemporal, privileged,
tagchecked, t);
if n == 31 then
CheckSPAlignment();
address = SP{64}();
else
address = X{64}(n);
end;
address = AddressAdd(address, offset, accdesc);
let data : bits(datasize) = Mem{datasize}(address, accdesc);
X{regsize}(t) = SignExtend{regsize}(data);
2026-03-26 20:27:25
2026-03_rel