Subject: [PATCH] arm: memset: zero out upper bytes in r1

From: [email-masked] (Andrey Ryabinin)
Date: Thu, 08 May 2014 11:59:02 +0400

On 05/08/14 03:42, Afzal Mohammed wrote:
> 
> int is to be converted to unsigned char in memset, would having above
> change immediately upon entry to memset rather than at a place where it
> won't always execute make intention clearer ? (although it doesn't make
> difference)
> 

I think it's better to keep it near other manipulations with r1.
Plus this will save us from executing extra instruction on 'memset -> 6 -> 5 -> return'
path (memset for size <= 3).

> ubfx r1, r1, #0, #8 would have given the needed typecasting, but seems
> it is available only on ARMv6T2 & above.
> 

Indeed. It might be wrapped it with #if #else, but it will be a bit ugly,
probably not worth to do.