x86doc › SHA256MSG2 - Perform a Final Calculation for the Next Four SHA256 Message Dwords

SHA256MSG2—Perform a Final Calculation for the Next Four SHA256 Message Dwords

Opcode/Instruction	Op/En	64/32 bit Mode Support	CPUID Feature Flag	Description
NP 0F 38 CD /r SHA256MSG2 xmm1, xmm2/m128	RM	V/V	SHA	Performs the final calculation for the next four SHA256 message dwords using previous message dwords from xmm1 and xmm2/m128, storing the result in xmm1.

Instruction Operand Encoding

Op/En	Operand 1	Operand 2	Operand 3
RM	ModRM:reg (r, w)	ModRM:r/m (r)	N/A

Description

The SHA256MSG2 instruction is one of two SHA2 message scheduling instructions. The instruction performs the final calculation for the next four SHA256 message dwords.

Operation

SHA256MSG2

W14 := SRC2[95:64] ;
W15 := SRC2[127:96] ;
W16 := SRC1[31: 0] + σ1( W14) ;
W17 := SRC1[63: 32] + σ1( W15) ;
W18 := SRC1[95: 64] + σ1( W16) ;
W19 := SRC1[127: 96] + σ1( W17) ;
DEST[127:96] := W19 ;
DEST[95:64] := W18 ;
DEST[63:32] := W17 ;
DEST[31:0] := W16;

Intel C/C++ Compiler Intrinsic Equivalent

SHA256MSG2 __m128i _mm_sha256msg2_epu32(__m128i, __m128i);

Flags Affected

None.

SIMD Floating-Point Exceptions

None.

Other Exceptions

See Table 2-21, “Type 4 Class Exception Conditions.”