Dolphin-emulated Wii games' RAM data are in reversed byte-order, is it Wii-native?

cimmy · 10-07-2012, 03:45 PM #1

I found that Dolphin-emulated Wii games place their data in RAM in a reversed byte-order.

for example, a number 256, in a PC's RAM, it's stored in this form: 00h, 01h.

but for Dolphin-emulated Wii games, the number 256 is 01h, 00h in RAM, reversed order compared to PC.

for Pcsx2-emulated PS2 games, the byte-order is normal, same as PC.

so I wonder, is this a Wii-native thing or a "feature" caused by Dolphin?

**delroth** · 10-07-2012, 04:07 PM #2

The GC/Wii CPU uses a big endian representation of data.

**Axxer** · 10-07-2012, 04:14 PM #3

(10-07-2012, 04:07 PM)delroth Wrote: The GC/Wii CPU uses a big endian representation of data.

That is weird.

I guess that is just one more way to make a system though.

**delroth** · 10-07-2012, 04:21 PM #4

Yeah, all these people writing numbers from left to right are so weird.

**NaturalViolence** · 10-07-2012, 04:36 PM #5

(10-07-2012, 04:14 PM)Axxer Wrote:
(10-07-2012, 04:07 PM)delroth Wrote: The GC/Wii CPU uses a big endian representation of data.

That is weird.

I guess that is just one more way to make a system though.

delroth Wrote:Yeah, all these people writing numbers from left to right are so weird.

**Axxer** · (This post was last modified: 10-07-2012, 04:58 PM by Axxer.)

*pours iced water over burn*

*gets frostbite*

It's been so long since I took ICT and learned all of this stuff... I need to refresh my memory on this.

EDIT: so my world has been destroyed as I have finally decided to research some into x86 only to learn that it does little-endian instead of big-endian. So my perception of the world of CPU instruction sets has been altered forever.

lamedude · 10-08-2012, 09:51 AM #7

Haswell is getting Atom's movbe instruction (allows swapping the high and low bits of a long value during a move). Would that be useful here?

**delroth** · 10-08-2012, 10:39 AM #8

If it's faster than mov/bswap then it will definitely be useful. I doubt it will be though, will probably be converted to the same uops internally.

**sktsqrl** · 10-08-2012, 01:31 PM #9

Haswell does have many similar improvements (all the "bitwise operations", or however they call them), though, so perhaps the internal implementations will be improved in some way as well.

edit - I mean the added BMI stuff, but the intel site seems to be impossible to search ...