LDNT1H (scalar plus immediate, single register)

Contiguous load non-temporal halfwords to vector (immediate index)

Contiguous load non-temporal of halfwords to elements of a vector register from the memory address generated by a 64-bit scalar base and immediate index in the range -8 to 7 which is multiplied by the vector's in-memory size, irrespective of predication, and added to the base address. Inactive elements will not cause a read from Device memory or signal a fault, and are set to zero in the destination vector.

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

313029282726252423222120191817161514131211109876543210
101001001000imm4111PgRnZt
msz<1>msz<0>

LDNT1H { <Zt>.H }, <Pg>/Z, [<Xn|SP>{, #<imm>, MUL VL}]

if !HaveSVE() && !HaveSME() then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer g = UInt(Pg); constant integer esize = 16; integer offset = SInt(imm4);

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.

<imm>

Is the optional signed immediate vector offset, in the range -8 to 7, defaulting to 0, encoded in the "imm4" field.

Operation

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

Operational information

If FEAT_SVE2 is implemented or FEAT_SME is implemented, then if PSTATE.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored when its governing predicate register contains the same value for each execution.


Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46

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