Re: endianness guide
On Thu, Feb 10, 2005 at 11:20:13PM -0500, Albert Cahalan wrote:
> I guess you must enjoy fixing zillions of apps to work
> on PowerPC. This must be exciting and enjoyable work.
> Discovering the problems is surely an extra pleasure,
> especially when your data gets destroyed.
But you're not bitter or anything.
> It's all worth it though, so you can support EBCDIC.
Actually, unsigned bytes are slightly more efficient than
signed bytes on powerpc. There is no instruction to directly
load and sign extend a byte like there is for halfwords (and
for words on ppc64). Because of this, if you want to load a
signed byte and do any operations on it, you need to sign
extend it after it is loaded. The extra instruction isn't a
huge deal, but it shouldn't be completely ignored either.
Brad Boyer
flar@allandria.com
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