MULSS (Multiply Scalar Single-Precision Floating-Point Values)

Opcodes

Opcode/Instruction Op/En 64/32-bit Mode CPUID Feature Flag Description
F3 0F 59 /r MULSS xmm1, xmm2/m32 RM V/V SSE Multiply the low single-precision floating-point value in xmm2/mem by the low single-precision floating-point value in xmm1.
VEX.NDS.LIG.F3.0F.WIG 59 /r VMULSS xmm1,xmm2, xmm3/m32 RVM V/V AVX Multiply the low single-precision floating-point value in xmm3/mem by the low single-precision floating-point value in xmm2.

Instruction Operand Encoding

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

Description

Multiplies the low single-precision floating-point value from the source operand (second operand) by the low single-precision floating-point value in the destination operand (first operand), and stores the single-precision floating-point result in the destination operand. The source operand can be an XMM register or a 32-bit memory location. The destination operand is an XMM register. The three high-order doublewords of the destination operand remain unchanged. See Figure 10-6 in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1, for an illustration of a scalar single-precision floating-point operation.

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

128-bit Legacy SSE version: The first source operand and the destination operand are the same. Bits (VLMAX-1:32) of the corresponding YMM destination register remain unchanged.

VEX.128 encoded version: Bits (VLMAX-1:128) of the destination YMM register are zeroed.

Operation

MULSS (128-bit Legacy SSE version)

DEST[31:0] ← DEST[31:0] * SRC[31:0]
DEST[VLMAX-1:32] (Unmodified)

VMULSS (VEX.128 encoded version)

DEST[31:0] ← SRC1[31:0] * SRC2[31:0]
DEST[127:32] ← SRC1[127:32]
DEST[VLMAX-1:128] ← 0

Intel C/C++ Compiler Intrinsic Equivalent

MULSS:

__m128 _mm_mul_ss(__m128 a, __m128 b)

SIMD Floating-Point Exceptions

Overflow, Underflow, Invalid, Precision, Denormal.

Other Exceptions

See Exceptions Type 3