LD1H (vector plus immediate)
Gather load unsigned halfwords to vector (immediate index)
Gather load of unsigned halfwords to active elements of a vector register from memory addresses generated by a vector base plus immediate index. The index is a multiple of 2 in the range 0 to 62. Inactive elements will not cause a read from Device memory or signal faults, and are set to zero in the destination vector.
This instruction is illegal when executed in Streaming SVE mode, unless FEAT_SME_FA64 is implemented and enabled.
Green
True
True
True
SM_0_only
It has encodings from 2 classes:
32-bit element
and
64-bit element
1
0
0
0
0
1
0
0
1
0
1
1
1
0
LD1H { <Zt>.S }, <Pg>/Z, [<Zn>.S{, #<imm>}]
if !IsFeatureImplemented(FEAT_SVE) then UNDEFINED;
constant integer t = UInt(Zt);
constant integer n = UInt(Zn);
constant integer g = UInt(Pg);
constant integer esize = 32;
constant integer msize = 16;
constant boolean unsigned = TRUE;
constant integer offset = UInt(imm5);
1
1
0
0
0
1
0
0
1
0
1
1
1
0
LD1H { <Zt>.D }, <Pg>/Z, [<Zn>.D{, #<imm>}]
if !IsFeatureImplemented(FEAT_SVE) then UNDEFINED;
constant integer t = UInt(Zt);
constant integer n = UInt(Zn);
constant integer g = UInt(Pg);
constant integer esize = 64;
constant integer msize = 16;
constant boolean unsigned = TRUE;
constant integer offset = UInt(imm5);
<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.
<Zn>
Is the name of the base scalable vector register, encoded in the "Zn" field.
<imm>
Is the optional unsigned immediate byte offset, a multiple of 2 in the range 0 to 62, defaulting to 0, encoded in the "imm5" field.
CheckNonStreamingSVEEnabled();
constant integer VL = CurrentVL;
constant integer PL = VL DIV 8;
constant integer elements = VL DIV esize;
constant bits(PL) mask = P[g, PL];
bits(VL) base;
bits(VL) result;
bits(msize) data;
constant integer mbytes = msize DIV 8;
constant boolean contiguous = FALSE;
constant boolean nontemporal = FALSE;
constant boolean tagchecked = TRUE;
constant AccessDescriptor accdesc = CreateAccDescSVE(MemOp_LOAD, nontemporal, contiguous,
tagchecked);
if AnyActiveElement(mask, esize) then
base = Z[n, VL];
for e = 0 to elements-1
if ActivePredicateElement(mask, e, esize) then
constant bits(64) baddr = ZeroExtend(Elem[base, e, esize], 64);
constant bits(64) addr = AddressAdd(baddr, offset * mbytes, accdesc);
data = Mem[addr, mbytes, accdesc];
Elem[result, e, esize] = Extend(data, esize, unsigned);
else
Elem[result, e, esize] = Zeros(esize);
Z[t, VL] = result;