Provide a skeleton for a64 instruction decoding in translate-a64.c,
by dividing instructions into the classes defined by the
ARM Architecture Reference Manual(DDI0487A_a) section C3.
Signed-off-by: NClaudio Fontana <claudio.fontana@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NRichard Henderson <rth@twiddle.net>