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SHA1H

SHA1 fixed rotate.

313029282726252423222120191817161514131211109876543210
0101111000101000000010RnRd

Advanced SIMD

SHA1H <Sd>, <Sn>

integer d = UInt(Rd);
integer n = UInt(Rn);
if !HaveSHA1Ext() then UNDEFINED;

Assembler Symbols

<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.

Operation

AArch64.CheckFPAdvSIMDEnabled();

bits(32) operand = V[n];    // read element [0] only,  [1-3] zeroed
V[d] = ROL(operand, 30);

Operational information

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.