STNT1D (scalar plus scalar, single register)

This instruction performs a contiguous non-temporal store of doublewords from elements of a vector register to the memory address generated by a 64-bit scalar base and scalar index that is multiplied by 8 and added to the base address. After each element access the index value is incremented, but the index register is not updated. Inactive elements are not written to memory.

A non-temporal store is a hint to the system that this data is unlikely to be referenced again soon.

SVE class

(FEAT_SVE || FEAT_SME)

Decode

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); if Rm == '11111' then EndOfDecode(Decode_UNDEF); constant integer t = UInt(Zt); constant integer n = UInt(Rn); constant integer m = UInt(Rm); constant integer g = UInt(Pg); constant integer esize = 64;

Assembler Symbols

<Zt>	Is the name of the scalable vector register to be transferred, encoded in the "Zt" field.

<Pg>	Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" field.

<Xn|SP>

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

<Xm>	Is the 64-bit name of the general-purpose offset register, encoded in the "Rm" field.

Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; bits(64) base; bits(64) offset; bits(64) addr; bits(VL) src; constant bits(PL) mask = P[g, PL]; constant integer mbytes = esize DIV 8; constant boolean contiguous = TRUE; constant boolean nontemporal = TRUE; constant boolean predicated = TRUE; constant boolean tagchecked = TRUE; constant AccessDescriptor accdesc = CreateAccDescSVE(MemOp_STORE, nontemporal, contiguous, predicated, tagchecked); if !AnyActiveElement(mask, esize) then if n == 31 && ConstrainUnpredictableBool(Unpredictable_CHECKSPNONEACTIVE) then CheckSPAlignment(); else if n == 31 then CheckSPAlignment(); src = Z[t, VL]; base = if n == 31 then SP[64] else X[n, 64]; offset = X[m, 64]; addr = AddressAdd(base, UInt(offset) * mbytes, accdesc); for e = 0 to elements-1 if ActivePredicateElement(mask, e, esize) then Mem[addr, mbytes, accdesc] = Elem[src, e, esize]; addr = AddressIncrement(addr, mbytes, accdesc);

Operational information

This instruction is a data-independent-time instruction as described in About PSTATE.DIT.

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
1	1	1	0	0	1	0	1	1	0	0	!= 11111					0	1	1	Pg			Rn					Zt
							msz				Rm