Intel® Architecture Instruction Set Extensions Programming Reference

INSTRUCTION SET REFERENCE - FMA
VFMSUB132SS/VFMSUB213SS/VFMSUB231SS — Fused Multiply-Subtract of Scalar Single-
Precision Floating-Point Values
Opcode/
Instruction
VEX.DDS.LIG.128.66.0F38.W0
9B /r
VFMSUB132SS xmm0, xmm1,
xmm2/m32
VEX.DDS.LIG.128.66.0F38.W0
AB /r
VFMSUB213SS xmm0, xmm1,
xmm2/m32
VEX.DDS.LIG.128.66.0F38.W0
BB /r
VFMSUB231SS xmm0, xmm1,
xmm2/m32
Description
Op/
En
64/32
-bit
Mode
CPUID
Feature
Flag
Description
A V/V FMA Multiply scalar single-precision floating-point value from xmm0 and
xmm2/mem, subtract xmm1 and put result in xmm0.
A V/V FMA Multiply scalar single-precision floating-point value from xmm0 and
xmm1, subtract xmm2/mem and put result in xmm0.
A V/V FMA Multiply scalar single-precision floating-point value from xmm1 and
xmm2/mem, 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
Performs a SIMD multiply-subtract computation on the low packed single-precision floating-point values using
three source operands and writes the multiply-add result 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.
VFMSUB132SS: Multiplies the low packed single-precision floating-point value from the first source operand to the
low packed single-precision floating-point value in the third source operand. From the infinite precision intermediate
result, subtracts the low packed single-precision floating-point values in the second source operand, performs
rounding and stores the resulting packed single-precision floating-point value to the destination operand (first
source operand).
VFMSUB213SS: Multiplies the low packed single-precision floating-point value from the second source operand to
the low packed single-precision floating-point value in the first source operand. From the infinite precision intermediate
result, subtracts the low packed single-precision floating-point value in the third source operand, performs
rounding and stores the resulting packed single-precision floating-point value to the destination operand (first
source operand).
VFMSUB231SS: Multiplies the low packed single-precision floating-point value from the second source to the low
packed single-precision floating-point value in the third source operand. From the infinite precision intermediate
result, subtracts the low packed single-precision floating-point value in the first source operand, performs rounding
and stores the resulting packed single-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 32-bit memory location and encoded in rm_field. The upper bits ([255:128]) 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 2.3.1, “FMA Instruction Operand Order and Arithmetic Behavior”.
6-32 Ref. # 319433-014