[MPlayer-dev-eng] [PATCH] negating unsigned in asm code

[Jindrich Makovicka]

Michael Niedermayer wrote:
> Hi
> 
> On Tuesday 28 June 2005 12:39, Reimar Döffinger wrote:
> 
>>Hi,
>>rgb2rgb_template.c causes a lot of crashes on AMD64, since the current
>>code first negates unsigned variables and then extends them to 64 bits,
>>the result being a very big positive value instead of a negative one.
>>One possibility would be making all unsigned signed.
>>The attached patch instead does the subtraction/negating in assembler,
>>which fixes this as well (a bit at the cost of readability, but not much
>>IMHO).
>>Is it okay to apply??
> 
> 
> no, you are changing operands which are marked as read only, while i suspect 
> it will work it might break with some versions of gcc as gcc expects read 
> only operands to be unchanged after the asm

Definitely. I recently encountered such breakage in early versions of
vf_fspp.

-- 
Jindrich Makovicka