SHA1MSG1—Perform an Intermediate Calculation for the Next Four SHA1 Message Dwords

Opcode/Instruction Op/En 64/32 bit Mode Support CPUID Feature Flag Description
NP 0F 38 C9 /r SHA1MSG1 xmm1, xmm2/m128 RM V/V SHA Performs an intermediate calculation for the next four SHA1 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) NA


The SHA1MSG1 instruction is one of two SHA1 message scheduling instructions. The instruction performs an inter-mediate calculation for the next four SHA1 message dwords.



W0 := SRC1[127:96] ;

W1 := SRC1[95:64] ;

W2 := SRC1[63: 32] ;

W3 := SRC1[31: 0] ;

W4 := SRC2[127:96] ;

W5 := SRC2[95:64] ;

DEST[127:96] := W2 XOR W0;

DEST[95:64] := W3 XOR W1;

DEST[63:32] := W4 XOR W2;

DEST[31:0] := W5 XOR W3;

Intel C/C++ Compiler Intrinsic Equivalent

SHA1MSG1: __m128i _mm_sha1msg1_epu32(__m128i, __m128i);

Flags Affected


SIMD Floating-Point Exceptions


Other Exceptions

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