VFMSUB132PD/VFMSUB213PD/VFMSUB231PD — Fused Multiply-Subtract of Packed Double-Precision Floating-Point Values

Opcode/Instruction	Op/En	64/32 -bit Mode	CPUID Feature Flag	Description
VEX.DDS.128.66.0F38.W1 9A /r VFMSUB132PD xmm0, xmm1, xmm2/m128	A	V/V	FMA	Multiply packed double-precision floating-point val-ues from xmm0 and xmm2/mem, subtract xmm1 and put result in xmm0.
VEX.DDS.128.66.0F38.W1 AA /r VFMSUB213PD xmm0, xmm1, xmm2/m128	A	V/V	FMA	Multiply packed double-precision floating-point val-ues from xmm0 and xmm1, subtract xmm2/mem and put result in xmm0.
VEX.DDS.128.66.0F38.W1 BA /r VFMSUB231PD xmm0, xmm1, xmm2/m128	A	V/V	FMA	Multiply packed double-precision floating-point val-ues from xmm1 and xmm2/mem, subtract xmm0 and put result in xmm0.
VEX.DDS.256.66.0F38.W1 9A /r VFMSUB132PD ymm0, ymm1, ymm2/m256	A	V/V	FMA	Multiply packed double-precision floating-point val-ues from ymm0 and ymm2/mem, subtract ymm1 and put result in ymm0.
VEX.DDS.256.66.0F38.W1 AA /r VFMSUB213PD ymm0, ymm1, ymm2/m256	A	V/V	FMA	Multiply packed double-precision floating-point val-ues from ymm0 and ymm1, subtract ymm2/mem and put result in ymm0.
VEX.DDS.256.66.0F38.W1 BA /r VFMSUB231PD ymm0, ymm1, ymm2/m256	A	V/V	FMA	Multiply packed double-precision floating-point val-ues from ymm1 and ymm2/mem, subtract ymm0 and put result in ymm0.

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

Performs a set of SIMD multiply-subtract computation on packed double-precision floating-point values using three source operands and writes the multiply-subtract results in the destination operand. The destination operand is also the first source operand. The second operand must be a SIMD register. The third source operand can be a SIMD register or a memory location.

VFMSUB132PD: Multiplies the two or four packed double-precision floating-point values from the first source operand to the two or four packed double-precision floating-point values in the third source operand. From the infi-nite precision intermediate result, subtracts the two or four packed double-precision floating-point values in the second source operand, performs rounding and stores the resulting two or four packed double-precision floating-point values to the destination operand (first source operand).

VFMSUB213PD: Multiplies the two or four packed double-precision floating-point values from the second source operand to the two or four packed double-precision floating-point values in the first source operand. From the infi-nite precision intermediate result, subtracts the two or four packed double-precision floating-point values in the third source operand, performs rounding and stores the resulting two or four packed double-precision floating-point values to the destination operand (first source operand).

VFMSUB231PD: Multiplies the two or four packed double-precision floating-point values from the second source to the two or four packed double-precision floating-point values in the third source operand. From the infinite preci-sion intermediate result, subtracts the two or four packed double-precision floating-point values in the first source operand, performs rounding and stores the resulting two or four packed double-precision floating-point values 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 128-bit memory location and encoded in rm_field. The upper 128 bits of the YMM destination register are zeroed.

VEX.256 encoded version: The destination operand (also first source operand) is a YMM register and encoded in reg_field. The second source operand is a YMM register and encoded in VEX.vvvv. The third source operand is a YMM register or a 256-bit memory location and encoded in rm_field.

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).

VFMSUB132PD DEST, SRC2, SRC3

IF (VEX.128) THEN
    MAXVL =2
ELSEIF (VEX.256)
    MAXVL = 4
FI
For i = 0 to MAXVL-1 {
    n = 64*i;
    DEST[n+63:n] ← RoundFPControl_MXCSR(DEST[n+63:n]*SRC3[n+63:n] - SRC2[n+63:n])
}
IF (VEX.128) THEN
DEST[VLMAX-1:128] ← 0
FI

VFMSUB213PD DEST, SRC2, SRC3

IF (VEX.128) THEN
    MAXVL =2
ELSEIF (VEX.256)
    MAXVL = 4
FI
For i = 0 to MAXVL-1 {
    n = 64*i;
    DEST[n+63:n] ← RoundFPControl_MXCSR(SRC2[n+63:n]*DEST[n+63:n] - SRC3[n+63:n])
}
IF (VEX.128) THEN
DEST[VLMAX-1:128] ← 0
FI

VFMSUB231PD DEST, SRC2, SRC3

IF (VEX.128) THEN
    MAXVL =2
ELSEIF (VEX.256)
    MAXVL = 4
FI
For i = 0 to MAXVL-1 {
    n = 64*i;
    DEST[n+63:n] ← RoundFPControl_MXCSR(SRC2[n+63:n]*SRC3[n+63:n] - DEST[n+63:n])
}
IF (VEX.128) THEN
DEST[VLMAX-1:128] ← 0
FI

Intel C/C++ Compiler Intrinsic Equivalent

VFMSUB132PD: __m128d _mm_fmsub_pd (__m128d a, __m128d b, __m128d c);

VFMSUB213PD: __m128d _mm_fmsub_pd (__m128d a, __m128d b, __m128d c);

VFMSUB231PD: __m128d _mm_fmsub_pd (__m128d a, __m128d b, __m128d c);

VFMSUB132PD: __m256d _mm256_fmsub_pd (__m256d a, __m256d b, __m256d c);

VFMSUB213PD: __m256d _mm256_fmsub_pd (__m256d a, __m256d b, __m256d c);

VFMSUB231PD: __m256d _mm256_fmsub_pd (__m256d a, __m256d b, __m256d c);

SIMD Floating-Point Exceptions

Overflow, Underflow, Invalid, Precision, Denormal

Other Exceptions

See Exceptions Type 2