VFNMSUB132SD/VFNMSUB213SD/VFNMSUB231SD — Fused Negative Multiply-Subtract of Scalar Double-Precision Floating-Point Values

Opcode/Instruction Op/En 64/32-bit Mode CPUID Feature Flag Description

VEX.DDS.LIG.128.66.0F38.W1 9F /r

VFNMSUB132SD xmm0, xmm1, xmm2/m64

 A V/V FMA Multiply scalar double-precision floating-point value from xmm0 and xmm2/mem, negate the multiplica-tion result and subtract xmm1 and put result in xmm0.

VEX.DDS.LIG.128.66.0F38.W1 AF /r

VFNMSUB213SD xmm0, xmm1, xmm2/m64

 A V/V FMA Multiply scalar double-precision floating-point value from xmm0 and xmm1, negate the multiplication result and subtract xmm2/mem and put result in xmm0.

VEX.DDS.LIG.128.66.0F38.W1 BF /r

VFNMSUB231SD xmm0, xmm1, xmm2/m64

 A V/V FMA Multiply scalar double-precision floating-point value from xmm1 and xmm2/mem, negate the multiplica-tion result and subtract xmm0 and put result in xmm0.

Instruction Operand Encoding

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

Description

VFNMSUB132SD: Multiplies the low packed double-precision floating-point value from the first source operand to the low packed double-precision floating-point value in the third source operand. From negated infinite precision intermediate result, subtracts the low double-precision floating-point value in the second source operand, performs rounding and stores the resulting packed double-precision floating-point value to the destination operand (first source operand).

VFNMSUB213SD: Multiplies the low packed double-precision floating-point value from the second source operand to the low packed double-precision floating-point value in the first source operand. From negated infinite precision intermediate result, subtracts the low double-precision floating-point value in the third source operand, performs rounding and stores the resulting packed double-precision floating-point value to the destination operand (first source operand).

VFNMSUB231SD: Multiplies the low packed double-precision floating-point value from the second source to the low packed double-precision floating-point value in the third source operand. From negated infinite precision interme-diate result, subtracts the low double-precision floating-point value in the first source operand, performs rounding and stores the resulting packed double-precision floating-point value to the destination operand (first source operand).

VEX.128 encoded version: The destination operand (also first source operand) is a XMM register and encoded in reg_field. The second source operand is a XMM register and encoded in VEX.vvvv. The third source operand is a XMM register or a 64-bit memory location and encoded in rm_field. The upper bits ([VLMAX-1:128]) of the YMM destination register are zeroed.

Compiler tools may optionally support a complementary mnemonic for each instruction mnemonic listed in the opcode/instruction column of the summary table. The behavior of the complementary mnemonic in situations involving NANs are governed by the definition of the instruction mnemonic defined in the opcode/instruction column. See also Section 14.5.1, “FMA Instruction Operand Order and Arithmetic Behavior” in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1.

Operation

In the operations below, "+", "-", and "*" symbols represent addition, subtraction, and multiplication operations with infinite precision inputs and outputs (no rounding).

VFNMSUB132SD DEST, SRC2, SRC3

DEST[63:0] ← RoundFPControl_MXCSR(- (DEST[63:0]*SRC3[63:0]) - SRC2[63:0])
DEST[127:64] ← DEST[127:64]
DEST[VLMAX-1:128] ← 0

VFNMSUB213SD DEST, SRC2, SRC3

DEST[63:0] ← RoundFPControl_MXCSR(- (SRC2[63:0]*DEST[63:0]) - SRC3[63:0])
DEST[127:64] ← DEST[127:64]
DEST[VLMAX-1:128] ← 0

VFNMSUB231SD DEST, SRC2, SRC3

DEST[63:0] ← RoundFPControl_MXCSR(- (SRC2[63:0]*SRC3[63:0]) - DEST[63:0])
DEST[127:64] ← DEST[127:64]
DEST[VLMAX-1:128] ← 0

Intel C/C++ Compiler Intrinsic Equivalent

VFNMSUB132SD: __m128d _mm_fnmsub_sd (__m128d a, __m128d b, __m128d c);

VFNMSUB213SD: __m128d _mm_fnmsub_sd (__m128d a, __m128d b, __m128d c);

VFNMSUB231SD: __m128d _mm_fnmsub_sd (__m128d a, __m128d b, __m128d c);

SIMD Floating-Point Exceptions

Overflow, Underflow, Invalid, Precision, Denormal

Other Exceptions

See Exceptions Type 3