Re: [Qemu-devel] [RFC PATCH 0/4] build: TARGET_ARCH/ARCH2/TYPE simplification

[Andreas Färber]

Am 20.05.2013 23:33, schrieb Peter Maydell:
> On 20 May 2013 21:57, Andreas Färber <address@hidden> wrote:
>> Am 20.05.2013 19:23, schrieb Paolo Bonzini:
>> Add to that
>>
>> - TARGET_BASE_ARCH in Makefile.target is assumed to be the name of the
>> target-* subdirectory, but this will not always be desirable.
> 
> Isn't it the name of the target-* subdirectory by definition?
> (ie we need to be able to set that somehow if you have a subarch
> that's piggybacking on another subarch, and this is how we set it).

The base architecture is by definition the architecture another one is
basing on. The base architecture's define is present for all derived
ones (e.g., TARGET_PPC for TARGET_PPC64).

>> For a long time already I have been carrying the following patch
>> introducing TARGET_ARCH_DIR:
>> https://github.com/afaerber/qemu-rl78/commit/9eddd60dae6603235fddf9070c73e5bf65edf292
>>
>> Still need to rebase that, but it looks as if there are no conflicts
>> with your series.
> 
> It seems to me that if you're going to put the source code in
> the target-rl78 directory you should make rl78 the
> TARGET_BASE_ARCH. Alternatively call the directory target-78k0
> if you want the TARGET_BASE_ARCH to be 78k0.

I tried that and it is awful for two reasons:
* 78k0 is not a valid identifier in C, so I can't write 78k0_cpu_foo.
* I only care about implementing RL78 but I know it has a documented
base architecture of 78K/0 that I would like to mark up to avoid the
issues we have with implementing older ARM versions after the fact. Ties
in with the topic of whether to autogenerate the default targets.

Andreas

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