[monocasa]

#2 For tight loops on the GBA you wanted 32bit ARM instructions in an area of RAM with 32bit accesses. There was a performance penalty both for using thumb and for running non thumb out of ROM (the bus to ROM was only 16bits). If there was a lack of WRAM for some reason it would totally make sense to put a tight loop into VRAM. (And for whatever reason Nintendo is really into putting random stuff into VRAM. On the DS, one of the ARM7 images would put WLAN packet buffers into an unused VRAM bank to reduce pressure on other RAM banks).

[smosher_]

That's fair. I had been assuming you'd use ITCM for tight loops regardless but I can't recall whether you can do that on GBA now that I think of it.

As for copying data around, yeah, if your emu can't copy data to/from VRAM in a sensible manner it's just not going to work out.

[vardump]

Putting WLAN buffer into VRAM is a good idea. Incoming packet probably generates DMA and packets arrive in an non-deterministic fashion. Less risk of DMA/bus saturation to main RAM.