Load LOAcquire register byte
This instruction loads a byte from memory, zero-extends it and writes it to a register.
If the destination register is not one of WZR or XZR, LDLARB loads from memory with Acquire semantics.
For more information about memory ordering semantics, see Load LOAcquire, Store LORelease and Load-Acquire, Load-AcquirePC, and Store-Release.
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 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | (1) | (1) | (1) | (1) | (1) | 0 | (1) | (1) | (1) | (1) | (1) | Rn | Rt | ||||||||
| size | L | Rs | o0 | Rt2 | |||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_LOR) then EndOfDecode(Decode_UNDEF); end; let t : integer{} = UInt(Rt); let n : integer{} = UInt(Rn); let acquire : boolean = TRUE; let tagchecked : boolean = n != 31;
| <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. |
var address : bits(64); let accdesc : AccessDescriptor = CreateAccDescLOR(MemOp_LOAD, tagchecked, acquire, t); if n == 31 then CheckSPAlignment(); address = SP{64}(); else address = X{64}(n); end; let data : bits(8) = Mem{8}(address, accdesc); X{32}(t) = ZeroExtend{32}(data);
This instruction is a data-independent-time instruction as described in About PSTATE.DIT.
2026-03_rel 2026-03-26 20:48:11
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