LD1H (scalar plus scalar)

Contiguous load unsigned halfwords to vector (scalar index)

Contiguous load of unsigned halfwords to elements of a vector register from the memory address generated by a 64-bit scalar base and scalar index which is multiplied by 2 and 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 not cause a read from Device memory or signal a fault, and are set to zero in the destination vector.

It has encodings from 3 classes: 16-bit element , 32-bit element and 64-bit element

16-bit element

313029282726252423222120191817161514131211109876543210
10100100101Rm010PgRnZt
dtype<3:1>dtype<0>

LD1H { <Zt>.H }, <Pg>/Z, [<Xn|SP>, <Xm>, LSL #1]

if !HaveSVE() && !HaveSME() then UNDEFINED; if Rm == '11111' then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer m = UInt(Rm); integer g = UInt(Pg); integer esize = 16; integer msize = 16; boolean unsigned = TRUE;

32-bit element

313029282726252423222120191817161514131211109876543210
10100100110Rm010PgRnZt
dtype<3:1>dtype<0>

LD1H { <Zt>.S }, <Pg>/Z, [<Xn|SP>, <Xm>, LSL #1]

if !HaveSVE() && !HaveSME() then UNDEFINED; if Rm == '11111' then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer m = UInt(Rm); integer g = UInt(Pg); integer esize = 32; integer msize = 16; boolean unsigned = TRUE;

64-bit element

313029282726252423222120191817161514131211109876543210
10100100111Rm010PgRnZt
dtype<3:1>dtype<0>

LD1H { <Zt>.D }, <Pg>/Z, [<Xn|SP>, <Xm>, LSL #1]

if !HaveSVE() && !HaveSME() then UNDEFINED; if Rm == '11111' then UNDEFINED; integer t = UInt(Zt); integer n = UInt(Rn); integer m = UInt(Rm); integer g = UInt(Pg); integer esize = 64; integer msize = 16; boolean unsigned = TRUE;

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(); integer elements = VL DIV esize; bits(64) base; bits(PL) mask = P[g]; bits(VL) result; bits(msize) data; bits(64) offset; constant integer mbytes = msize DIV 8; if HaveMTEExt() then SetTagCheckedInstruction(TRUE); 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]; offset = X[m]; for e = 0 to elements-1 if ElemP[mask, e, esize] == '1' then bits(64) addr = base + (UInt(offset) + e) * mbytes; data = Mem[addr, mbytes, AccType_NORMAL]; Elem[result, e, esize] = Extend(data, esize, unsigned); else Elem[result, e, esize] = Zeros(); Z[t] = result;


Internal version only: isa v33.11seprel, AdvSIMD v29.05, pseudocode v2021-09_rel, sve v2021-09_rc3d ; Build timestamp: 2021-10-06T11:41

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