x86 Instruction Set Reference

MOVSLDUP - Move Packed Single-FP Low and Duplicate

Opcode Mnemonic Description
F3 0F 12 /r MOVSLDUP xmm1, xmm2/m128 Move 128 bits representing packed SP data elements from xmm2/m128 to xmm1 register and duplicate low.
Description

The linear address corresponds to the address of the least-significant byte of the referenced memory data. When a memory address is indicated, the 16 bytes of data at memory location m128 are loaded and the single-precision elements in positions 0 and 2 are duplicated. When the register-register form of this operation is used, the same operation is performed but with data coming from the 128-bit source register.
Operation 
if(source == m128) {
	//load instruction
	xmm1[0..31] = m128[0..31];
	xmm1[32..63] = m128[0..31]
	xmm1[64..95] = m128[64..95];
	xmm1[96..127] = m128[64..95];
}
else {
	//move instruction
	xmm1[0..31] = xmm2[0..31];
	xmm1[32..63] = xmm2[0..31];
	xmm1[64..95] = xmm2[64..95];
	xmm1[96..127] = xmm2[64..95];
}
Exceptions
General protection exception if not aligned on 16-byte boundary, regardless of segment.
Numeric Exceptions
None.
Protected Mode Exceptions
#GP(0)For an illegal memory operand effective address in the CS, DS, ES, FS or GS segments.
#GP(0)For an illegal memory operand effective address in the CS, DS, ES, FS or GS segments.
#SS(0)For an illegal address in the SS segment.
#PF(fault-code)For a page fault.
#NMIf TS bit in CR0 is set.
Real-Address Mode Exceptions
#GP(0)If any part of the operand would lie outside of the effective address space from 0 to 0FFFFH.
#GP(0)If any part of the operand would lie outside of the effective address space from 0 to 0FFFFH.
#NMIf TS bit in CR0 is set.
Virtual-8086 Mode Exceptions
#GP(0)If any part of the operand would lie outside of the effective address space from 0 to 0FFFFH.
#GP(0)If any part of the operand would lie outside of the effective address space from 0 to 0FFFFH.
#NMIf TS bit in CR0 is set.
#UDIf CR0.EM = 1. If CR4.OSFXSR(bit 9) = 0. If CPUID.SSE3(ECX bit 0) = 0.
Instruction Latency Throughput Execution Unit
CPUID0F3n0F3n0F3n
MOVSLDUP xmm1, xmm262FP_MOVE