From the GCC manual.
> GCC permits a C structure to have no members:
struct empty {
};
> The structure has size zero. In C++, empty structures are part of the
> language. G++ treats empty structures as if they had a single member of type
> char.
I was not aware of the different behavior in C++.
This fixes every maple example--most were broken for multiple reasons, including
this one.
This also enables SH4 caching. This includes linking code/data into the P1
area (previously this was not the case).
The maple examples (which indeed involve much use of DMA) require much work to
successfully work with the operand and copyback caches. The vibration example
currently is the most complete, though I should consider more on how I want to
structure maple response operand cache invalidation more generally.
Though I did spend much time thinking about this, my idea was not correct.
The "tearing" and "previous frame is being shown while it is being drawn" is
simply because that's exactly what the logic in holly/core.cpp did.
This is no longer the case--by the time the newly-created core_flip function is
called, the core render is complete, and we should switch the FB_R_SOF1 to the
current framebuffer, not the one that is going to be written on next frame.
This also modifies alt.lds so that (non-startup) code now runs in the P1 area,
with operand/instruction/copyback caches enabled. This caused a 10x speed
increase in my testing.
There are still texture sampling issues that I don't understand. Until
I properly understand this, using (bitmap) fonts that have
power-of-two dimensions seem to produce "acceptable but incorrect"
results.
