19.51 FMULX (scalar)

Floating-point Multiply extended.

Syntax

FMULX Hd, Hn, Hm ; Scalar half precision

FMULX Vd, Vn, Vm ; Scalar single-precision and double-precision

Where:

Hd
Is the 16-bit name of the SIMD and FP destination register.
Hn
Is the 16-bit name of the first SIMD and FP source register.
Hm
Is the 16-bit name of the second SIMD and FP source register.
V
Is a width specifier, and can be either 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.
m
Is the number of the second SIMD and FP source register.

Architectures supported (scalar)

Supported in the Arm®v8.2 architecture and later.

Usage

Floating-point Multiply extended. This instruction multiplies corresponding floating-point values in the vectors of the two source SIMD and FP registers, places the resulting floating-point values in a vector, and writes the vector to the destination SIMD and FP register.

If one value is zero and the other value is infinite, the result is 2.0. In this case, the result is negative if only one of the values is negative, otherwise the result is positive.

This instruction can generate a floating-point exception. Depending on the settings in FPCR, the exception results in either a flag being set in FPSR, or a synchronous exception being generated. For more information, see Floating-point exception traps in the Arm® Architecture Reference Manual Arm®v8, for Arm®v8‑A architecture profile.

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.

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