LDGM
Load tag multiple
This instruction reads a naturally aligned block of N Allocation Tags,
where the size of N is identified in GMID_EL1.BS, and writes the Allocation Tag read from address A to the destination register at
4*A<7:4>+3:4*A<7:4>. Bits of the destination register not written with an
Allocation Tag are set to 0.
This instruction is UNDEFINED at EL0.
This instruction generates an Unchecked access.
1
1
0
1
1
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
LDGM <Xt>, [<Xn|SP>]
if !IsFeatureImplemented(FEAT_MTE2) then UNDEFINED;
constant integer t = UInt(Xt);
constant integer n = UInt(Xn);
<Xt>
Is the 64-bit name of the general-purpose destination register, encoded in the "Xt" field.
<Xn|SP>
Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Xn" field.
if PSTATE.EL == EL0 then UNDEFINED;
bits(64) data = Zeros(64);
bits(64) address;
if n == 31 then
CheckSPAlignment();
address = SP[];
else
address = X[n, 64];
constant integer size = 4 * (2 ^ (UInt(GMID_EL1.BS)));
address = Align(address, size);
constant integer count = size >> LOG2_TAG_GRANULE;
integer index = UInt(address<LOG2_TAG_GRANULE+3:LOG2_TAG_GRANULE>);
constant boolean devstoreunpred = FALSE;
constant AccessDescriptor accdesc = CreateAccDescLDGSTG(MemOp_LOAD, devstoreunpred);
for i = 0 to count-1
constant bits(4) tag = AArch64.MemTag[address, accdesc];
Elem[data, index, 4] = tag;
address = AddressIncrement(address, TAG_GRANULE, accdesc);
index = index + 1;
X[t, 64] = data;