[Ffmpeg-devel] [PATCH] Upate of Zaurus IWMMXT patch

[Måns Rullgård]

Vadim Lebedev <vadim at mbdsys.com> writes:

> David Bateman wrote:
>
>> +static void clear_blocks_iwmmxt(DCTELEM *blocks)
>>+{
>>+    __asm __volatile(
>>+                "wzero wr0                      \n\t"
>>+                "mov r1, #(128 * 6 / 32)        \n\t"
>>+                "1:                             \n\t"
>>+                "wstrd wr0, [%0]                \n\t"
>>+                "wstrd wr0, [%0, #8]            \n\t"
>>+                "wstrd wr0, [%0, #16]           \n\t"
>>+                "wstrd wr0, [%0, #24]           \n\t"
>>+                "subs r1, r1, #1                \n\t"
>>+                "add %0, %0, #32                \n\t"
>>+                "bne 1b                         \n\t"
>>+                : "+r"(blocks)
>>+                :
>>+                : "r1"
>>+        );
>>+}
>>+
>>
>>
> I'm affraid my ARM asm skills are a little  rusty but
> shouldn't  the order  of these 2 lines be inverted, becase ADD
> instruction clears Z flag?

No.  The flags are only set by instructions with the 's' modifier,
i.e. add does not alter the flags, but adds does.  That's the beauty
of ARM assembler.

-- 
M?ns Rullg?rd
mans at mansr.com