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STZGM

Store Tag and Zero Multiple writes a naturally aligned block of N Allocation Tags and stores zero to the associated data locations, where the size of N is identified in DCZID_EL0.BS, and the Allocation Tag written to address A is taken from the source register bits<3:0>.

This instruction is undefined at EL0.

This instruction generates an Unchecked access.

This instruction is Unallocated when ID_AA64PFR1_EL1.MTE == 0b0001.

Integer
(Armv8.5)

313029282726252423222120191817161514131211109876543210
1101100100100000000000XnXt

Integer

STZGM <Xt>, [<Xn|SP>]

integer t = UInt(Xt);
integer n = UInt(Xn);

Assembler Symbols

<Xt>

Is the 64-bit name of the general-purpose register to be transferred, 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.

Operation

if PSTATE.EL == EL0 then
    UndefinedFault();

bits(64) data = X[t];
bits(4) tag = data<3:0>;
bits(64) address;
if n == 31 then
    CheckSPAlignment();
    address = SP[];
else
    address = X[n];

integer size = 4 * (2 ^ (UInt(DCZID_EL0.BS)));
address = Align(address, size);
integer count = size >> LOG2_TAG_GRANULE;

for i = 0 to count-1
    AArch64.MemTag[address] = tag;
    Mem[address, TAG_GRANULE, AccType_NORMAL] = Zeros(8 * TAG_GRANULE);
    address = address + TAG_GRANULE;
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