LD1D (scalar plus immediate, single register)

Contiguous load unsigned doublewords to vector (immediate index)

Contiguous load of unsigned doublewords 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.

It has encodings from 2 classes: SVE and SVE2

SVE

313029282726252423222120191817161514131211109876543210
101001011110imm4101PgRnZt
dtype<3:1>dtype<0>

LD1D { <Zt>.D }, <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 = 64; constant integer msize = 64; boolean unsigned = TRUE; integer offset = SInt(imm4);

SVE2
(FEAT_SVE2p1)

313029282726252423222120191817161514131211109876543210
101001011001imm4001PgRnZt
dtype<1>dtype<0>

LD1D { <Zt>.Q }, <Pg>/Z, [<Xn|SP>{, #<imm>, MUL VL}]

if !HaveSVE2p1() then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer g = UInt(Pg); constant integer esize = 128; constant integer msize = 64; boolean unsigned = TRUE; 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

if esize < 128 then CheckSVEEnabled(); else CheckNonStreamingSVEEnabled(); 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; bits(msize) data; constant integer mbytes = msize DIV 8; boolean contiguous = TRUE; boolean nontemporal = FALSE; 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 ElemP[mask, e, esize] == '1' then integer eoff = (offset * elements) + e; bits(64) addr = base + eoff * mbytes; data = Mem[addr, mbytes, accdesc]; Elem[result, e, esize] = Extend(data, esize, unsigned); else Elem[result, e, esize] = Zeros(esize); Z[t, VL] = result;


Internal version only: isa v33.53, AdvSIMD v29.11, pseudocode v2022-09_rel, sve v2022-09_rel ; Build timestamp: 2022-09-30T16:37

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