VEC_SHASIGMA_BE(ARG1,ARG2,ARG3)

Purpose

Performs a secure hash computation in accordance with Federal Information Processing Standards FIPS-180-3, which is a specification for the Secure Hash Standard.

This built-in function is valid only when -qarch is set to target POWER8® processors.

Class

Elemental function

Argument type and attributes

ARG1

An INTENT(IN) UNSIGNED(4) or UNSIGNED(8) vector

ARG2

An INTENT(IN) integer

The argument must be a constant expression with a value of 0 or 1. It selects the function type, which can be either lowercase sigma (σ) or uppercase sigma (∑).

ARG3

An INTENT(IN) integer

The argument must be a constant expression with a value in the range 0 - 15 inclusive. It selects the function subtype, which can be either sigma-0 (σ0 or ∑0) or sigma-1 (σ1 or ∑1).

Result type and attributes

The result has the same type and type parameters as ARG1.

Result value

• If ARG1 is an UNSIGNED(4) vector, for each element i (i = 0,1,2,3) of ARG1, element i of the returned value is the result of the following SHA-256 function:
  • σ0(x[i]), if ARG2 is 0 and bit i of the 4-bit ARG3 is 0
  • σ1(x[i]), if ARG2 is 0 and bit i of the 4-bit ARG3 is 1
  • ∑0(x[i]), if ARG2 is nonzero and bit i of the 4-bit ARG3 is 0
  • ∑1(x[i]), if ARG2 is nonzero and bit i of the 4-bit ARG3 is 1
• If ARG1 is an UNSIGNED(8) vector, for each element i (i = 0,1) of ARG1, element i of the returned value is the result of the following SHA-512 function:
  • σ0(x[i]), if ARG2 is 0 and bit 2*i of the 4-bit ARG3 is 0
  • σ1(x[i]), if ARG2 is 0 and bit 2*i of the 4-bit ARG3 is 1
  • ∑0(x[i]), if ARG2 is nonzero and bit 2*i of the 4-bit ARG3 is 0
  • ∑1(x[i]), if ARG2 is nonzero and bit 2*i of the 4-bit ARG3 is 1