MOVLPS—Move Low Packed Single-Precision Floating-Point Values

Opcode/Instruction	Op/En	64/32-bit Mode	CPUID Feature Flag	Description
0F 12 /r MOVLPS xmm, m64	RM	V/V	SSE	Move two packed single-precision floating-point values from m64 to low quadword of xmm.
0F 13 /r MOVLPS m64, xmm	MR	V/V	SSE	Move two packed single-precision floating-point values from low quadword of xmm to m64.
VEX.NDS.128.0F.WIG 12 /r VMOVLPS xmm2, xmm1, m64	RVM	V/V	AVX	Merge two packed single-precision floating-point values from m64 and the high quadword of xmm1.
VEX.128.0F.WIG 13/r VMOVLPS m64, xmm1	MR	V/V	AVX	Move two packed single-precision floating-point values from low quadword of xmm1 to m64.

Instruction Operand Encoding

Op/En	Operand 1	Operand 2	Operand 3	Operand 4
RM	ModRM:reg (r, w)	ModRM:r/m (r)	NA	NA
MR	ModRM:r/m (w)	ModRM:reg (r)	NA	NA
RVM	ModRM:reg (w)	VEX.vvvv (r)	ModRM:r/m (r)	NA

Description

This instruction cannot be used for register to register or memory to memory moves.

128-bit Legacy SSE load:

Moves two packed single-precision floating-point values from the source 64-bit memory operand and stores them in the low 64-bits of the destination XMM register. The upper 64bits of the XMM register are preserved. The upper 128-bits of the corresponding YMM destination register are preserved.

In 64-bit mode, use of the REX.R prefix permits this instruction to access additional registers (XMM8-XMM15).

VEX.128 encoded load:

Loads two packed single-precision floating-point values from the source 64-bit memory operand (third operand), merges them with the upper 64-bits of the first source XMM register (second operand), and stores them in the low 128-bits of the destination XMM register (first operand). The upper 128-bits of the destination YMM register are zeroed.

128-bit store:

Loads two packed single-precision floating-point values from the low 64-bits of the XMM register source (second operand) to the 64-bit memory location (first operand).

Note: VMOVLPS (store) (VEX.128.0F 13 /r) is legal and has the same behavior as the existing 0F 13 store. For VMOVLPS (store) (VEX.128.0F 13 /r) instruction version, VEX.vvvv is reserved and must be 1111b otherwise instruction will #UD.

If VMOVLPS is encoded with VEX.L= 1, an attempt to execute the instruction encoded with VEX.L= 1 will cause an #UD exception.

Operation

MOVLPS (128-bit Legacy SSE load)

DEST[63:0] ← SRC[63:0]
DEST[VLMAX-1:64] (Unmodified)

VMOVLPS (VEX.128 encoded load)

DEST[63:0] ← SRC2[63:0]
DEST[127:64] ← SRC1[127:64]
DEST[VLMAX-1:128] ← 0

VMOVLPS (store)

DEST[63:0] ← SRC[63:0]

Intel C/C++ Compiler Intrinsic Equivalent

MOVLPS:

__m128 _mm_loadl_pi ( __m128 a, __m64 *p)

MOVLPS:

void _mm_storel_pi (__m64 *p, __m128 a)

SIMD Floating-Point Exceptions

None.

Other Exceptions

See Exceptions Type 5; additionally

#UD	If VEX.L= 1. If VEX.vvvv ≠ 1111B.