Re: [PATCH] idct_sse2_skal: fix overread in TEST_ROW on x86_64

Thanks, Peter! Patch applied.

Best regards,
Michael


On 2024-12-20 10:35, Peter Ross wrote:
> on x86_64 the _EAX/_EDX macros expand to rax/rdx registers and are 8 
> bytes
> wide. it is therefore sufficient to test only the %1 and %1+8 pixel 
> offsets in
> TEST_ROW macro.
> 
> testing the offsets %1+4 and %1+12 is unnecessary on x86_64. the later 
> case also
> causes an overread when processing the final pixel block (chroma v 
> block). this
> overread is detected by valgrind.
> ---
>  xvidcore/src/dct/x86_asm/fdct_sse2_skal.asm | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/xvidcore/src/dct/x86_asm/fdct_sse2_skal.asm
> b/xvidcore/src/dct/x86_asm/fdct_sse2_skal.asm
> index 4816ea6..a172e14 100644
> --- a/xvidcore/src/dct/x86_asm/fdct_sse2_skal.asm
> +++ b/xvidcore/src/dct/x86_asm/fdct_sse2_skal.asm
> @@ -365,10 +365,15 @@ cglobal fdct_sse2_skal
>  
> ;-----------------------------------------------------------------------------
> 
>  %macro TEST_ROW 2     ; %1:src,  %2:label x8
> +%ifdef ARCH_IS_X86_64
> +  mov _EAX, [%1   ]
> +  mov _EDX, [%1+ 8]
> +%else
>    mov _EAX, [%1   ]
>    mov _EDX, [%1+ 8]
>    or  _EAX, [%1+ 4]
>    or  _EDX, [%1+12]
> +%endif
>    or  _EAX, _EDX
>    jz near %2
>  %endmacro