LDNT1D (scalar plus scalar, consecutive registers)

Contiguous load non-temporal of doublewords to multiple consecutive vectors (scalar index)

Contiguous load non-temporal of doublewords to elements of two or four consecutive vector registers from the memory address generated by a 64-bit scalar base and scalar index which is added to the base address. After each element access the index value is incremented, but the index register is not updated.

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.

It has encodings from 2 classes: Two registers and Four registers

Two registers
(FEAT_SVE2p1)

313029282726252423222120191817161514131211109876543210
10100000000Rm011PNgRnZt1
msz<1>msz<0>N

LDNT1D { <Zt1>.D-<Zt2>.D }, <PNg>/Z, [<Xn|SP>, <Xm>, LSL #3]

if !HaveSME2() && !HaveSVE2p1() then UNDEFINED; integer n = UInt(Rn); integer m = UInt(Rm); integer g = UInt('1':PNg); constant integer nreg = 2; integer t = UInt(Zt:'0'); constant integer esize = 64;

Four registers
(FEAT_SVE2p1)

313029282726252423222120191817161514131211109876543210
10100000000Rm111PNgRnZt01
msz<1>msz<0>N

LDNT1D { <Zt1>.D-<Zt4>.D }, <PNg>/Z, [<Xn|SP>, <Xm>, LSL #3]

if !HaveSME2() && !HaveSVE2p1() then UNDEFINED; integer n = UInt(Rn); integer m = UInt(Rm); integer g = UInt('1':PNg); constant integer nreg = 4; integer t = UInt(Zt:'00'); constant integer esize = 64;

Assembler Symbols

<Zt1>

For the two registers variant: is the name of the first scalable vector register to be transferred, encoded as "Zt" times 2.

For the four registers variant: is the name of the first scalable vector register to be transferred, encoded as "Zt" times 4.

<Zt4>

Is the name of the fourth scalable vector register to be transferred, encoded as "Zt" times 4 plus 3.

<Zt2>

Is the name of the second scalable vector register to be transferred, encoded as "Zt" times 2 plus 1.

<PNg>

Is the name of the governing scalable predicate register PN8-PN15, with predicate-as-counter encoding, encoded in the "PNg" 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

if HaveSVE2p1() then CheckSVEEnabled(); else CheckStreamingSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant integer mbytes = esize DIV 8; bits(64) offset; bits(64) base; bits(PL) pred = P[g, PL]; bits(PL * nreg) mask = CounterToPredicate(pred<15:0>, PL * nreg); array [0..3] of bits(VL) values; boolean contiguous = TRUE; boolean nontemporal = TRUE; boolean tagchecked = TRUE; 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]; offset = X[m, 64]; for r = 0 to nreg-1 for e = 0 to elements-1 if ActivePredicateElement(mask, r * elements + e, esize) then integer eoff = UInt(offset) + r * elements + e; bits(64) addr = GenerateAddress(base, eoff * mbytes, accdesc); Elem[values[r], e, esize] = Mem[addr, mbytes, accdesc]; else Elem[values[r], e, esize] = Zeros(esize); for r = 0 to nreg-1 Z[t+r, VL] = values[r];

Operational information

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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