[AArch64][PATCH 1/3] Support ARMv8.2 FP16 floating point instructions.

ARMv8.2 adds 16-bit floating point operations as an optional extension
to the ARMv8 FP support. This patch set adds support for the 16-bit FP
instructions to binutils, enabling the instructions when both +fp and
+fp16 architecture extensions are enabled.

The patches in this series:
- Add a feature macro for use by the encoding/decoding mechanism.
- Adjust a utility function, used when disassembling, to support 16-bit
  floating point values.
- Add the new scalar floating-point instructions.

This patch adds the feature macro FP_F16 to the AArch64 encoding/decoding
mechanism, enabling it when both +fp and +fp16 are selected.

opcodes/
2015-11-27  Matthew Wahab  <matthew.wahab@arm.com>

	* aarch64-tbl.h (aarch64_feature_fp_f16): New.
	(FP_F16): New.

Change-Id: Ie370e43e3d77a7d54b4416b4be901b363a37f3d5