LDRSW (literal)

Load register signed word (literal)

This instruction calculates an address from the PC value and an immediate offset, loads a word from memory, and writes it to a register. For information about addressing modes, see Load/Store addressing modes.

Encoding: Literal

313029282726252423222120191817161514131211109876543210
10011000
opcVRimm19Rt

LDRSW <Xt>, <label>

Decoding algorithm

constant integer t = UInt(Rt);
constant boolean nontemporal = FALSE;
constant boolean tagchecked = FALSE;

constant bits(64) offset = SignExtend(imm19:'00', 64);

Operation

constant bits(64) address = PC64 + offset;
constant boolean privileged = PSTATE.EL != EL0;
constant AccessDescriptor accdesc = CreateAccDescGPR(MemOp_LOAD, nontemporal, privileged,
                                                     tagchecked);

constant bits(32) data = Mem[address, 4, accdesc];
X[t, 64] = SignExtend(data, 64);

Explanations

<Xt>: Is the 64-bit name of the general-purpose register to be loaded, encoded in the "Rt" field.
<label>: Is the program label from which the data is to be loaded. Its offset from the address of this instruction, in the range +/-1MB, is encoded as "imm19" times 4.

Operational Notes

If PSTATE.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored.