LDNP
Load pair of registers, with non-temporal hint
This instruction calculates an
address from a base register value and an immediate offset,
loads two 32-bit words or
two 64-bit doublewords from memory,
and writes them to
two registers.
For information about addressing modes, see
Load/Store addressing modes.
For information about non-temporal pair instructions, see
Load/Store non-temporal pair.
For information about the CONSTRAINED UNPREDICTABLE behavior of this instruction, see Architectural Constraints on UNPREDICTABLE behaviors, and particularly LDNP.
If PSTATE.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored.
x
0
1
0
1
0
0
0
0
1
0
LDNP <Wt1>, <Wt2>, [<Xn|SP>{, #<imm>}]
1
LDNP <Xt1>, <Xt2>, [<Xn|SP>{, #<imm>}]
// Empty.
<Wt1>
Is the 32-bit name of the first general-purpose register to be transferred, encoded in the "Rt" field.
<Wt2>
Is the 32-bit name of the second general-purpose register to be transferred, encoded in the "Rt2" field.
<Xn|SP>
Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field.
<imm>
For the 32-bit variant: is the optional signed immediate byte offset, a multiple of 4 in the range -256 to 252, defaulting to 0 and encoded in the "imm7" field as <imm>/4.
<imm>
For the 64-bit variant: is the optional signed immediate byte offset, a multiple of 8 in the range -512 to 504, defaulting to 0 and encoded in the "imm7" field as <imm>/8.
<Xt1>
Is the 64-bit name of the first general-purpose register to be transferred, encoded in the "Rt" field.
<Xt2>
Is the 64-bit name of the second general-purpose register to be transferred, encoded in the "Rt2" field.
if opc<0> == '1' then UNDEFINED;
constant integer t = UInt(Rt);
constant integer t2 = UInt(Rt2);
constant integer n = UInt(Rn);
constant boolean nontemporal = TRUE;
constant integer scale = 2 + UInt(opc<1>);
constant integer datasize = 8 << scale;
constant bits(64) offset = LSL(SignExtend(imm7, 64), scale);
constant boolean tagchecked = n != 31;
boolean rt_unknown = FALSE;
if t == t2 then
constant Constraint c = ConstrainUnpredictable(Unpredictable_LDPOVERLAP);
assert c IN {Constraint_UNKNOWN, Constraint_UNDEF, Constraint_NOP};
case c of
when Constraint_UNKNOWN rt_unknown = TRUE; // Result is UNKNOWN
when Constraint_UNDEF UNDEFINED;
when Constraint_NOP ExecuteAsNOP();
bits(64) address;
bits(64) address2;
constant integer dbytes = datasize DIV 8;
bits(datasize) data1;
bits(datasize) data2;
constant boolean privileged = PSTATE.EL != EL0;
AccessDescriptor accdesc = CreateAccDescGPR(MemOp_LOAD, nontemporal, privileged,
tagchecked);
if n == 31 then
CheckSPAlignment();
address = SP[];
else
address = X[n, 64];
address = AddressAdd(address, offset, accdesc);
if IsFeatureImplemented(FEAT_LSE2) then
accdesc.ispair = TRUE;
constant bits(2*datasize) full_data = Mem[address, 2 * dbytes, accdesc];
if BigEndian(accdesc.acctype) then
data2 = full_data<(datasize-1):0>;
data1 = full_data<(2*datasize-1):datasize>;
else
data1 = full_data<(datasize-1):0>;
data2 = full_data<(2*datasize-1):datasize>;
else
address2 = AddressIncrement(address, dbytes, accdesc);
data1 = Mem[address , dbytes, accdesc];
data2 = Mem[address2, dbytes, accdesc];
if rt_unknown then
data1 = bits(datasize) UNKNOWN;
data2 = bits(datasize) UNKNOWN;
X[t, datasize] = data1;
X[t2, datasize] = data2;