Guarded Control Stack unprivileged Store stores a doubleword from a register to memory. The address that is used for the store is calculated from a base register.
Memory accesses made by the instruction behave as if the instruction was executed at EL0 if the Effective value of PSTATE.UAO is 0 and either:
Otherwise, the memory access operates with the restrictions determined by the Exception level at which the instruction is executed.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | Rn | Rt | ||||||||
| opc | |||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_GCS) then UNDEFINED; integer t = UInt(Rt); integer n = UInt(Rn);
| <Xt> |
Is the 64-bit name of the general-purpose register to be transferred, encoded in the "Rt" field. |
| <Xn|SP> |
Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field. |
bits(64) address; bits(64) data; bits(2) effective_el = if AArch64.IsUnprivAccessPriv() then PSTATE.EL else EL0; if effective_el == PSTATE.EL then CheckGCSSTREnabled(); boolean privileged = effective_el != EL0; AccessDescriptor accdesc = CreateAccDescGCS(MemOp_STORE, privileged); if n == 31 then CheckSPAlignment(); address = SP[]; else address = X[n, 64]; data = X[t, 64]; Mem[address, 8, accdesc] = data;
Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45
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