SHA1H SHA1 fixed rotate SHA1 fixed rotate. If PSTATE.DIT is 1: The execution time of this instruction is independent of: The values of the data supplied in any of its registers. The values of the NZCV flags. The response of this instruction to asynchronous exceptions does not vary based on: The values of the data supplied in any of its registers. The values of the NZCV flags. 0 1 0 1 1 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 1 0 SHA1H <Sd>, <Sn> if !IsFeatureImplemented(FEAT_SHA1) then UNDEFINED; constant integer d = UInt(Rd); constant integer n = UInt(Rn); <Sd> Is the 32-bit name of the SIMD&FP destination register, encoded in the "Rd" field. <Sn> Is the 32-bit name of the SIMD&FP source register, encoded in the "Rn" field. AArch64.CheckFPAdvSIMDEnabled(); constant bits(32) operand = V[n, 32]; // read element [0] only, [1-3] zeroed V[d, 32] = ROL(operand, 30);