SM4EKEY
SM4 key
This instruction takes an input as a 128-bit vector from the first source SIMD&FP register
and a 128-bit constant from the second SIMD&FP register. It derives four iterations
of the output key, in accordance with the SM4 standard, returning the 128-bit result
to the destination SIMD&FP register.
This instruction is a data-independent-time instruction as described in About PSTATE.DIT.
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SM4EKEY <Vd>.4S, <Vn>.4S, <Vm>.4S
if !IsFeatureImplemented(FEAT_SM4) then EndOfDecode(Decode_UNDEF); end;
let d : integer{} = UInt(Rd);
let n : integer{} = UInt(Rn);
let m : integer{} = UInt(Rm);
<Vd>
Is the name of the SIMD&FP destination register, encoded in the "Rd" field.
<Vn>
Is the name of the first SIMD&FP source register, encoded in the "Rn" field.
<Vm>
Is the name of the second SIMD&FP source register, encoded in the "Rm" field.
AArch64_CheckFPAdvSIMDEnabled();
let Vm : bits(128) = V{}(m);
var intval : bits(32);
var const : bits(32);
var roundresult : bits(128);
roundresult = V{128}(n);
for index = 0 to 3 do
const = Vm[index*:32];
intval = roundresult[127:96] XOR roundresult[95:64] XOR roundresult[63:32] XOR const;
for i = 0 to 3 do
intval[i*:8] = Sbox(intval[i*:8]);
end;
intval = intval XOR ROL(intval, 13) XOR ROL(intval, 23);
intval = intval XOR roundresult[31:0];
roundresult[31:0] = roundresult[63:32];
roundresult[63:32] = roundresult[95:64];
roundresult[95:64] = roundresult[127:96];
roundresult[127:96] = intval;
end;
V{128}(d) = roundresult;
2026-03-12 12:23:09
2025-09_rel_asl1