# VFMSUB132PS/VFMSUB213PS/VFMSUB231PS (Fused Multiply-Subtract of Packed Single-Precision Floating-Point Values)

## Opcodes

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

VEX.DDS.128.66.0F38.W0 9A /r
VFMSUB132PS xmm0, xmm1, xmm2/m128 |
A | V/V | FMA | Multiply packed single-precision floating-point values from xmm0 and xmm2/mem, subtract xmm1 and put result in xmm0. |

VEX.DDS.128.66.0F38.W0 AA /r
VFMSUB213PS xmm0, xmm1, xmm2/m128 |
A | V/V | FMA | Multiply packed single-precision floating-point values from xmm0 and xmm1, subtract xmm2/mem and put result in xmm0. |

VEX.DDS.128.66.0F38.W0 BA /r
VFMSUB231PS xmm0, xmm1, xmm2/m128 |
A | V/V | FMA | Multiply packed single-precision floating-point values from xmm1 and xmm2/mem, subtract xmm0 and put result in xmm0. |

VEX.DDS.256.66.0F38.W0 9A /r
VFMSUB132PS ymm0, ymm1, ymm2/m256 |
A | V/V | FMA | Multiply packed single-precision floating-point values from ymm0 and ymm2/mem, subtract ymm1 and put result in ymm0. |

VEX.DDS.256.66.0F38.W0 AA /r
VFMSUB213PS ymm0, ymm1, ymm2/m256 |
A | V/V | FMA | Multiply packed single-precision floating-point values from ymm0 and ymm1, subtract ymm2/mem and put result in ymm0. |

VEX.DDS.256.66.0F38.0 BA /r
VFMSUB231PS ymm0, ymm1, ymm2/m256 |
A | V/V | FMA | Multiply packed single-precision floating-point values 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 single-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.

VFMSUB132PS: Multiplies the four or eight packed single-precision floating-point values from the first source operand to the four or eight packed single-precision floating-point values in the third source operand. From the infi-nite precision intermediate result, subtracts the four or eight packed single-precision floating-point values in the second source operand, performs rounding and stores the resulting four or eight packed single-precision floating-point values to the destination operand (first source operand).

VFMSUB213PS: Multiplies the four or eight packed single-precision floating-point values from the second source operand to the four or eight packed single-precision floating-point values in the first source operand. From the infi-nite precision intermediate result, subtracts the four or eight packed single-precision floating-point values in the third source operand, performs rounding and stores the resulting four or eight packed single-precision floating-point values to the destination operand (first source operand).

VFMSUB231PS: Multiplies the four or eight packed single-precision floating-point values from the second source to the four or eight packed single-precision floating-point values in the third source operand. From the infinite preci-sion intermediate result, subtracts the four or eight packed single-precision floating-point values in the first source operand, performs rounding and stores the resulting four or eight packed single-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).

**VFMSUB132PS DEST, SRC2, SRC3**

IF (VEX.128) THEN MAXVL =4 ELSEIF (VEX.256) MAXVL = 8 FI For i = 0 to MAXVL-1 { n = 32*i; DEST[n+31:n] ← RoundFPControl_MXCSR(DEST[n+31:n]*SRC3[n+31:n] - SRC2[n+31:n]) } IF (VEX.128) THEN DEST[VLMAX-1:128] ← 0 FI

**VFMSUB213PS DEST, SRC2, SRC3**

IF (VEX.128) THEN MAXVL =4 ELSEIF (VEX.256) MAXVL = 8 FI For i = 0 to MAXVL-1 { n = 32*i; DEST[n+31:n] ← RoundFPControl_MXCSR(SRC2[n+31:n]*DEST[n+31:n] - SRC3[n+31:n]) } IF (VEX.128) THEN DEST[VLMAX-1:128] ← 0 FI

**VFMSUB231PS DEST, SRC2, SRC3**

IF (VEX.128) THEN MAXVL =4 ELSEIF (VEX.256) MAXVL = 8 FI For i = 0 to MAXVL-1 { n = 32*i; DEST[n+31:n] ← RoundFPControl_MXCSR(SRC2[n+31:n]*SRC3[n+31:n] - DEST[n+31:n]) } IF (VEX.128) THEN DEST[VLMAX-1:128] ← 0 FI

## Intel C/C++ Compiler Intrinsic Equivalent

VFMSUB132PS: __m128 _mm_fmsub_ps (__m128 a, __m128 b, __m128 c);

VFMSUB213PS: __m128 _mm_fmsub_ps (__m128 a, __m128 b, __m128 c);

VFMSUB231PS: __m128 _mm_fmsub_ps (__m128 a, __m128 b, __m128 c);

VFMSUB132PS: __m256 _mm256_fmsub_ps (__m256 a, __m256 b, __m256 c);

VFMSUB213PS: __m256 _mm256_fmsub_ps (__m256 a, __m256 b, __m256 c);

VFMSUB231PS: __m256 _mm256_fmsub_ps (__m256 a, __m256 b, __m256 c);

## SIMD Floating-Point Exceptions

Overflow, Underflow, Invalid, Precision, Denormal

## Other Exceptions

See Exceptions Type 2