Using as: AArch64 Extensions

9.1.2 Architecture Extensions

The table below lists the permitted architecture extensions that are supported by the assembler and the conditions under which they are automatically enabled.

Multiple extensions may be specified, separated by a +. Extension mnemonics may also be removed from those the assembler accepts. This is done by prepending no to the option that adds the extension. Extensions that are removed must be listed after all extensions that have been added.

Enabling an extension that requires other extensions will automatically cause those extensions to be enabled. Similarly, disabling an extension that is required by other extensions will automatically cause those extensions to be disabled.

Extension	Minimum Architecture	Enabled by default	Description
`compnum`	ARMv8.2-A	ARMv8.3-A or later	Enable the complex number SIMD extensions. This implies `fp16` and `simd`.
`crc`	ARMv8-A	ARMv8.1-A or later	Enable CRC instructions.
`crypto`	ARMv8-A	No	Enable cryptographic extensions. This implies `fp` and `simd`.
`fp`	ARMv8-A	ARMv8-A or later	Enable floating-point extensions.
`fp16`	ARMv8.2-A	ARMv8.2-A or later	Enable ARMv8.2 16-bit floating-point support. This implies `fp`.
`lor`	ARMv8-A	ARMv8.1-A or later	Enable Limited Ordering Regions extensions.
`lse`	ARMv8-A	ARMv8.1-A or later	Enable Large System extensions.
`pan`	ARMv8-A	ARMv8.1-A or later	Enable Privileged Access Never support.
`profile`	ARMv8.2-A	No	Enable statistical profiling extensions.
`ras`	ARMv8-A	ARMv8.2-A or later	Enable the Reliability, Availability and Serviceability extension.
`rcpc`	ARMv8.2-A	ARMv8.3-A or later	Enable the weak release consistency extension.
`rdma`	ARMv8-A	ARMv8.1-A or later	Enable ARMv8.1 Advanced SIMD extensions. This implies `simd`.
`simd`	ARMv8-A	ARMv8-A or later	Enable Advanced SIMD extensions. This implies `fp`.
`sve`	ARMv8.2-A	No	Enable the Scalable Vector Extensions. This implies `fp16`, `simd` and `compnum`.
`dotprod`	ARMv8.2-A	No	Enable the Dot Product extension. This implies `simd`.