LD1ROB (scalar plus immediate)
Contiguous load and replicate thirty-two bytes (immediate index)
Load thirty-two contiguous bytes to elements of a 256-bit (octaword) vector from the memory address generated by a 64-bit scalar base address and immediate index that is a multiple of 32 in the range -256 to +224 added to the base address.
Inactive elements will not cause a read from Device memory or signal a fault, and are set to zero.
The resulting 256-bit vector is then replicated to fill the destination vector. The instruction requires that the Effective SVE vector length is at least 256 bits.
Only the first thirty-two predicate elements are used and higher numbered predicate elements are ignored.
ID_AA64ZFR0_EL1.F64MM indicates whether this instruction is implemented.
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
1
0
1
0
0
1
0
0
0
0
1
0
0
0
1
LD1ROB { <Zt>.B }, <Pg>/Z, [<Xn|SP>{, #<imm>}]
if !IsFeatureImplemented(FEAT_SVE) || !IsFeatureImplemented(FEAT_F64MM) then UNDEFINED;
constant integer t = UInt(Zt);
constant integer n = UInt(Rn);
constant integer g = UInt(Pg);
constant integer esize = 8;
constant integer offset = SInt(imm4);
<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 byte offset, a multiple of 32 in the range -256 to 224, defaulting to 0, encoded in the "imm4" field.
CheckNonStreamingSVEEnabled();
constant integer VL = CurrentVL;
constant integer PL = VL DIV 8;
if VL < 256 then UNDEFINED;
constant integer elements = 256 DIV esize;
bits(64) base;
constant bits(PL) mask = P[g, PL]; // low bits only
bits(64) addr;
bits(256) result;
constant integer mbytes = esize DIV 8;
constant boolean contiguous = TRUE;
constant boolean nontemporal = FALSE;
constant boolean tagchecked = n != 31;
constant 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];
addr = AddressAdd(base, offset * elements * mbytes, accdesc);
for e = 0 to elements-1
if ActivePredicateElement(mask, e, esize) then
Elem[result, e, esize] = Mem[addr, mbytes, accdesc];
else
Elem[result, e, esize] = Zeros(esize);
addr = AddressIncrement(addr, mbytes, accdesc);
Z[t, VL] = ZeroExtend(Replicate(result, VL DIV 256), VL);