STNP

Store pair of registers, with non-temporal hint

This instruction calculates an address from a base register value and an immediate offset, and stores two 32-bit words or two 64-bit doublewords to the calculated address, from two registers. For information about addressing modes, see Load/Store addressing modes. For information about non-temporal pair instructions, see Load/Store non-temporal pair.

313029282726252423222120191817161514131211109876543210
x010100000imm7Rt2RnRt
opcVRL

Encoding for the 32-bit variant

Applies when (opc == 00)

STNP <Wt1>, <Wt2>, [<Xn|SP>{, #<imm>}]

Encoding for the 64-bit variant

Applies when (opc == 10)

STNP <Xt1>, <Xt2>, [<Xn|SP>{, #<imm>}]

Decode for all variants of this encoding

let t : integer{} = UInt(Rt); let t2 : integer{} = UInt(Rt2); let n : integer{} = UInt(Rn); let nontemporal : boolean = TRUE; let scale : integer{} = 2 + UInt(opc[1]); let datasize : integer{} = 8 << scale; let offset : bits(64) = LSL(SignExtend{64}(imm7), scale); let tagchecked : boolean = n != 31;

Assembler Symbols

<Wt1>

Is the 32-bit name of the first general-purpose register to be transferred, encoded in the "Rt" field.

<Wt2>

Is the 32-bit name of the second general-purpose register to be transferred, encoded in the "Rt2" field.

<Xn|SP>

Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field.

<imm>

For the "32-bit" variant: is the optional signed immediate byte offset, a multiple of 4 in the range -256 to 252, defaulting to 0 and encoded in the "imm7" field as <imm>/4.

For the "64-bit" variant: is the optional signed immediate byte offset, a multiple of 8 in the range -512 to 504, defaulting to 0 and encoded in the "imm7" field as <imm>/8.

<Xt1>

Is the 64-bit name of the first general-purpose register to be transferred, encoded in the "Rt" field.

<Xt2>

Is the 64-bit name of the second general-purpose register to be transferred, encoded in the "Rt2" field.

Operation

var address : bits(64); let dbytes : integer{} = datasize DIV 8; let privileged : boolean = PSTATE.EL != EL0; let ispair : boolean = TRUE; let accdesc : AccessDescriptor = CreateAccDescGPR(MemOp_STORE, nontemporal, privileged, tagchecked, ispair, t, t2); if n == 31 then CheckSPAlignment(); address = SP{64}(); else address = X{64}(n); end; address = AddressAdd(address, offset, accdesc); let data : bits(2*datasize)= (if BigEndian(accdesc.acctype) then X{datasize}(t) ::X{datasize}(t2) else X{datasize}(t2)::X{datasize}(t)); Mem{2*datasize}(address, accdesc) = data;

Operational information

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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