Load register halfword (unscaled)
This instruction calculates an address from a base register and an immediate offset, loads a halfword from memory, zero-extends it, and writes it to a register. For information about addressing modes, see Load/Store addressing modes.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| 0 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | imm9 | 0 | 0 | Rn | Rt | ||||||||||||||||
| size | VR | opc | |||||||||||||||||||||||||||||
constant bits(64) offset = SignExtend(imm9, 64);
| <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. |
constant integer n = UInt(Rn); constant integer t = UInt(Rt); constant integer datasize = 16; constant boolean nontemporal = FALSE; constant boolean tagchecked = n != 31;
bits(64) address; constant boolean privileged = PSTATE.EL != EL0; constant AccessDescriptor accdesc = CreateAccDescGPR(MemOp_LOAD, nontemporal, privileged, tagchecked); if n == 31 then CheckSPAlignment(); address = SP[64]; else address = X[n, 64]; address = AddressAdd(address, offset, accdesc); constant bits(datasize) data = Mem[address, datasize DIV 8, accdesc]; X[t, 32] = ZeroExtend(data, 32);
If PSTATE.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored.
Internal version only: aarchmrs v2024-12_rel, pseudocode v2024-12_rel ; Build timestamp: 2024-12-15T22:18
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