x86 Instruction Set Reference

Creates a mask made up of the most significant bit of each byte of the source operand (second operand) and stores the result in the low byte or word of the destination operand (first operand).

The source operand is an MMX technology register or an XMM register; the destination operand is a general-purpose register. When operating on 64-bit operands, the byte mask is 8 bits; when operating on 128-bit operands, the byte mask is 16-bits.

if(OperandSize == 64) {
	//PMOVMSKB instruction with 64-bit source operand:
	r32[0] = Source[7];
	r32[1] = Source[15];
	r32[2] = Source[23];
	r32[3] = Source[31];
	r32[4] = Source[39];
	r32[5] = Source[47];
	r32[6] = Source[55];
	r32[7] = Source[63];
	r32[8..31] = 0;
}
else {
	//PMOVMSKB instruction with 128-bit source operand:
	r32[0] = Source[7];
	r32[1] = Source[15];
	r32[2] = Source[23];
	r32[3] = Source[31];
	r32[4] = Source[39];
	r32[5] = Source[47];
	r32[6] = Source[55];
	r32[7] = Source[63];
	r32[8] = Source[71];
	r32[9] = Source[79];
	r32[10] = Source[87];
	r32[11] = Source[95];
	r32[12] = Source[103];
	r32[13] = Source[111];
	r32[14] = Source[119];
	r32[15] = Source[127];
	r32[16..31] = 0;
}

None.