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FMULX (scalar, by element)

Floating-point Multiply extended (by element).

Syntax

FMULX Vd, Vn, Vm.Ts[index]

Where:

V
Is a width specifier, and can be H, S, or D.
d
Is the number of the SIMD and FP destination register.
n
Is the number of the first SIMD and FP source register.
Ts
Is an element size specifier, and can be H, S, or D.
index
Is the element index, H.
Vm
Is the name of the second SIMD and FP source register in the range 0 to 31.

Architectures supported (scalar)

Supported in ARMv8.2 and later.

Usage

Floating-point Multiply extended (by element). This instruction multiplies the floating-point values in the vector elements in the first source SIMD and FP register by the specified floating-point value in the second source SIMD and FP register, places the results in a vector, and writes the vector to the destination SIMD and FP register.

Before each multiplication, a check is performed for whether one value is infinite and the other is zero. In this case, if only one of the values is negative, the result is 2.0, otherwise the result is -2.0.

This instruction can generate a floating-point exception. Depending on the settings in FPCR in the ARMv8-A Architecture Reference Manual, the exception results in either a flag being set in FPSR in the ARMv8-A Architecture Reference Manual or a synchronous exception being generated. For more information, see Floating-point exception traps in the ARMv8-A Architecture Reference Manual.

Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.

The following table shows the valid specifier combinations:

Table 19-9 FMULX (Scalar, single-precision and double-precision) specifier combinations

V Ts index
S S 0 to 3
D D 0 or 1