SHA1C

SHA1 hash update (choose)

SHA1 hash update (choose).

Advanced SIMD
(FEAT_SHA1)

313029282726252423222120191817161514131211109876543210
01011110000Rm000000RnRd
sizeopcode

Encoding

SHA1C <Qd>, <Sn>, <Vm>.4S

Decode for this encoding

if !IsFeatureImplemented(FEAT_SHA1) then EndOfDecode(Decode_UNDEF); end; let d : integer{} = UInt(Rd); let n : integer{} = UInt(Rn); let m : integer{} = UInt(Rm);

Assembler Symbols

<Qd>

Is the 128-bit name of the SIMD&FP source and destination, encoded in the "Rd" field.

<Sn>

Is the 32-bit name of the second SIMD&FP source register, encoded in the "Rn" field.

<Vm>

Is the name of the third SIMD&FP source register, encoded in the "Rm" field.

Operation

AArch64_CheckFPAdvSIMDEnabled(); var x : bits(128) = V{}(d); var y : bits(32) = V{}(n); // Note: 32 not 128 bits wide let w : bits(128) = V{}(m); for e = 0 to 3 do let t : bits(32) = SHAchoose(x[63:32], x[95:64], x[127:96]); y = y + ROL(x[31:0], 5) + t + w[e*:32]; x[63:32] = ROL(x[63:32], 30); let yx : bits(160) = ROL(y::x, 32); (y, x) = (yx[159:128], yx[127:0]); end; V{128}(d) = x;

Operational information

This instruction is a data-independent-time instruction as described in About PSTATE.DIT.


2026-03_rel 2026-03-26 20:48:11

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