SHA256H2

SHA256 hash update (part 2)

SHA256 hash update (part 2).

Encoding: Advanced SIMD

Variants: FEAT_SHA256 (ARMv8.0)

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0	1	0	1	1	1	1	0	0	0	0						0	1	0	1	0	0
								size			Rm								P			Rn					Rd

SHA256H2 <Qd>, <Qn>, <Vm>.4S

Decoding algorithm

if !IsFeatureImplemented(FEAT_SHA256) then EndOfDecode(Decode_UNDEF);
constant integer d = UInt(Rd);
constant integer n = UInt(Rn);
constant integer m = UInt(Rm);

Operation

AArch64.CheckFPAdvSIMDEnabled();

constant boolean part1 = FALSE;
V[d, 128] = SHA256hash(V[n, 128], V[d, 128], V[m, 128], part1);

Explanations

<Qd>: Is the 128-bit name of the SIMD&FP source and destination, 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.

Operational Notes

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.