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SHA512H2

SHA512 Hash update part 2 takes the values from the three 128-bit source SIMD&FP registers and produces a 128-bit output value that combines the sigma0 and majority functions of two iterations of the SHA512 computation. It returns this value to the destination SIMD&FP register.

This instruction is implemented only when FEAT_SHA512 is implemented.

Advanced SIMD
(Armv8.2)

313029282726252423222120191817161514131211109876543210
11001110011Rm100001RnRd

SHA512H2 <Qd>, <Qn>, <Vm>.2D

if !HaveSHA512Ext() then UNDEFINED;
integer d = UInt(Rd);
integer n = UInt(Rn);
integer m = UInt(Rm);

Assembler Symbols

<Qd>

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

<Qn>

Is the 128-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();

bits(128) Vtmp;
bits(64) NSigma0;
bits(128) X = V[n];
bits(128) Y = V[m];
bits(128) W = V[d];

NSigma0 = ROR(Y<63:0>, 28) EOR ROR(Y<63:0>, 34) EOR ROR(Y<63:0>, 39);
Vtmp<127:64> = (X<63:0> AND Y<127:64>) EOR (X<63:0> AND Y<63:0>) EOR (Y<127:64> AND Y<63:0>);
Vtmp<127:64> = (Vtmp<127:64> + NSigma0 + W<127:64>);
NSigma0 = ROR(Vtmp<127:64>, 28) EOR ROR(Vtmp<127:64>, 34) EOR ROR(Vtmp<127:64>, 39);
Vtmp<63:0> = (Vtmp<127:64> AND Y<63:0>) EOR (Vtmp<127:64> AND Y<127:64>) EOR (Y<127:64> AND Y<63:0>);
Vtmp<63:0> = (Vtmp<63:0> + NSigma0 + W<63:0>);

V[d] = Vtmp;

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.
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