[Ohrrpgce] SVN: teeemcee/7974 Change asm gosub implementation to preserve 16 byte stack alignment.

[Ralph Versteegen]

No, this doesn't fix anything.

Unlike Linux, which requires 16 byte stack alignment but will never
actually throw a SIGBUS unless you use SSE (and we pass options to gcc
to prevent that in code we compile), on Mac you have to keep the stack
aligned or even a PRINT will crash.
However while it wasn't much work to update the backend, it turns out
that there are no assemblers for OSX that support Intel syntax. Apple
gas is broken, LLVM is *really* broken, and FSF gas hasn't been ported
at all. So the FB gas backend, while having complete support, can't be
used.

So this patch isn't useful yet, but if my patch is merged and we drop
support FB 1.05 and earlier, then we will be able to stop passing
-mpreferred-stack-boundary to gcc.

On 30 April 2016 at 02:06, James Paige <Bob at hamsterrepublic.com> wrote:
> Does this one need to be merged for callipygous+1?
>
> On Thu, Apr 28, 2016 at 7:30 AM, <subversion at hamsterrepublic.com> wrote:
>>
>> teeemcee
>> 2016-04-28 07:30:30 -0700 (Thu, 28 Apr 2016)
>> 316
>> Change asm gosub implementation to preserve 16 byte stack alignment.
>>
>> This is only important on Macs (where the asm implementation isn't used)
>> and on Linux (where I haven't seen any problems so far, despite the fact
>> that FB doesn't align the stack although it's meant to, so GOSUB is the
>> least of our worries there.)
>> ---
>> U   wip/config.bi